DECONTAMINATION OF PESTICIDE RESIDUES ON FRUITS AND VEGETABLES
The effect of household preparation or commercial processing to minimize the pesticide residue levels on raw agricultural commodities (RACs) is significant as they normally decline the residues. These types of processung strudies are intended: To provide info around the transfer of residues in the RAC for the processed products, in an effort to calculate reduction factor or concentration variables; To allow and more realistic estimate to be produced in the dietary intake of pesticide residues; To establish MRLs for residues in processed goods exactly where necessary, in line with requirements of national regulatory authorities or international standards. Preferably, RAC samples utilised in processing research need to include field treated quantifiable residues as close as possible for the MRL, so that measurable residues are obtained, and transfer variables for the various processed commodities could be determined. A transfer aspect gives the ratio in the residue concentration inside the processed commodity to that in the RAC. For instance when the residue concentration is 0.five mg/kg in olives and 0.2 mg/kg in olive oil, the transfer issue is 0.2/0.5=0.four. A issue 1 (= concentration aspect) indicates a concentration impact from the processing procedures. Enhancing the residues either by increasing the application rates, shortening the pre-harvest interval (PHI) or spiking the RAC together with the active ingredient and its metabolites in vitro is not, as and rule, desirable. Spiking is only acceptable if the RAC residues may be shown to consist only of surface residues. However, in some cases, specifically exactly where residues inside the RAC are close for the analytical limit of determination, field therapy at exaggerated rates or shortened PHIs is advisable to obtain adequate residue levels for the processing research.
The initial step in household or commercial meals processing would be the preparation of meals making use of numerous mechanical processes, such as removing broken or soiled things or components of crops, washing, peeling, trimming or hulling. This often leads to important declines in the volume of pesticide residues inside the remaining edible portions (Petersen et al., 1996; Celik et al., 1995; Schattenberg et al., 1996).
WASHING
Household washing procedures are usually carried out with operating or standing water at moderate temperatures. Detergents, chlorine or ozone might be added for the wash water to enhance the effectiveness from the washing process (Ong et al., 1996). If necessary, several washing methods can be conducted consequently. The effects rely on the physiochemical properties of the pesticides, like water solubility, hydrolytic rate continual, volatility and octanol-water partition coefficient (Pow), in conjunction together with the actual physical location in the residues; washing processes cause reduction of hydrophilic residues which are located on the surface of the crops. In addition, the temperature from the washing water along with the type of washing has an influence on the residue level. As pointed out by Holland et al. (1994), hot washing as well as the addition of detergents are far more effective than cold water washing. Washing coupled with gentle rubbing by hand below tap water for 1 min dislodges pesticide residues considerably (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues are not removed significantly by washing. Table (1) shows examples from the effects of washing around the residue levels of distinct pesticides applied to fruits and vegetables.
PEELING
The outer leaves of vegetables often include residues of pesticides applied throughout the expanding season. As a result, peeling or trimming procedures reduce the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables using a knife is frequent household practice. Many examples show that most of the residues concentration is positioned in or on the peel. Peeling on the RACs may remove greater than 50% from the pesticide residues present within the commodity. As a result, removal of the peel achieves practically comprehensive removal of residues, so leaving tiny inside the edible portions. This is specially essential for fruits that are not eaten with their peels, for example bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot decreased the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer issue of 0.two. Nonetheless, the peel from commercial peeling processes may be used as animal feed or for the production of crucial oils (citrus) or pectin (citrus, apple etc.). For such industrial processes, it is important to recognize that especially non-systemic surface residues are typically concentrated within the peel. For systemic pesticides, peeling may not be as successful as shown by Sheikhorgan et al (1994). Soon after application of thiometon on cucumbers, no reduction of residue levels might be detected within the peeled cucumbers. Under the Codex Alimentarius, as in other international requirements, MRLs refer towards the entire fruits, which can be suitable for assessing compliance with GAP. These MRLs are of restricted significance, nevertheless, in assessing dietary exposure to pesticides from fresh fruits, that are peeled (Holland et al.,1994).
COOKING Cooking procedures at diverse temperatures, the duration on the procedure, the amount of water or food additives, as well as the variety of method (open or closed) may have an effect around the residue level. Usually, residues are decreased during the cooking process by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Many studies had been reported on the dissipation of pesticides in crops throughout cooking. Furthermore for the research summarized in table 1 the behavior on the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos during cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased during the cooking method corresponding for the boiling time. Based on their water solubility, some pesticides have been translocated from the raw supplies into the cooking water. However, the pesticide remained within the processed meals based on their octanol-water partition coefficient, which can be an indicator of hydrophilic or lipophilic properties of the compound. In exceptional instances, cooking processes could trigger pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), which is a lot far more potent than the parent compound (Leparulo-Lofus et al.,1992). Another instance may be the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, throughout heating processes (Petersen et al., 1996).
Dipping in chemical answer Sodium chloride answer is largely employed to decontaminate the pesticide residues from different fruits and vegetables .there are many studies to prove the efficacy of salt water washing to dislodge the pesticides from crops. In this method, sample of chopped fruits and vegetables is place in a beaker containing 5% sodium chloride remedy. After 15 minutes the plant samples are gently rubbed by hand in salt remedy and alt water is decanted. The examples on the effect of salt resolution therapy on the residue levels of various pesticides applied to vegetables happen to be shown in table 1. Kumar et al (2000) reported that dipping of green chillies in 2% salt answer for ten minute followed by water wash prove to be efficient, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and five days right after spray of triazophos (700g a.i./ha) while the acephate residues have been removed to an extent of 78.95% at zero day. Following same approach Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and five days right after spraying of cypermethrin in chillies. Dip therapy of fruits in NaCl resolution, HCl, acetic acid, NaOH remedy, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids in comparison with 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b). Water remedy of NaOH, acetic acid potassium dichromate and soap answer utilized as decontaminating agents for tom . The therapy of fruits with 2% tamarind resolution dip for 5 minute followed by tap water wash and steam cooking for ten min. was located to take away the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, 100 and 100% respectively. Remedy with 2% salt resolution was equally powerful. Dip treatments in the brinjal fruit wioth water, sodium chloride, HCl remedy, acetic acid resolution or potassium permanganate resolution had been all identified to eliminate 30-33% on the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH remedy 40-45% and Teepol (a detergent) resolution 50-60%. The impact of washing in decreasing the residues decreased progressively at the second and third harvests. Several experiments had been carried out with the three typical household preparations viz. washing with water, salt water washing and cooking to asses their relative efficiencies in minimizing the pesticide residues in different vegetables. The outcomes happen to be summarized in the following table.
Table: Impact of washing, salt water washing and cooking on pesticide residue levels.
Crop Pesticide % of Residue dislodged *ResultReference Washing with waterSalt water washing Cooking CauliflowerMethamidophos41-4846-4746.94 -53.54Largest reduction was brought about by cooking. Jacob and Verma (1990)
Okra Methamidophos 64-72 19-58 58-64Washing with water could get rid of maximum residues indicating its maximum solubility in water even though all the processes reduce down the TMRL values.Jacob and Verma (1990)
CauliflowerAlpha-cypermethrin 7-38_ 12-17Washing was discovered to be a lot more efficient than cooking probably due to the thermal stability of cypermethrin.Malik et al (1997)
Cabbage
Chlorpyriphos
Quinalphos
38
41
52.13
56.50
54.3
55With the 3 processes residues were decreased to some extent. They could not minimize the residue beneath the MRL. Therefore a waiting period of a minimum of 1 and two weeks, respectively, was recommended irrespective of washing cooking for quinalphos and chlorpyriphos on cabbage. Nagesh and Verma (1997)
Cow pea Metasystox
Carbalyl 84.three
87.5 86.4
88.7 83.4
80.8Only boiling from the pod samples could decontaminate the residues present of surface or inside the tissue towards the extent of protected limits by 10th day of treatment.Dikshit et al (1984)
Cauliflower Malathion 60 70 80Cooking was located to become most powerful and lowered the TMRL worth from one particular week to zero days.Jacob and Verma (1989)
Bhindi Quinalphos 61.84-64.35 43-53 78-82 Each washing with water and salt water washing brought down the residues below the MRL at zero days, cooking also did this resulting maximum reduction of residues. Jacob and Verma (1985)
Cabbage Malathion
Carbaryl
Pyrethroids 64.60
75.40
22.06 (av.) -
-
-
83.97
89.62
56.72 (av.) The extent of decontamination was greater due to cooking in comparison with washing for all insecticides. Bhatia and Verma (1994) Leaves and curds of cauliflower heads of cabbage and pods of Indian colza
Green beans
Methamidophos
DDT
Malathion
Carbaryl
65.71-77.67
71
96
52
-
-
-
-
80-88.88
52(cooked) 66 (pressure cooked)
99(cooked) 99(p.cooked)
77cooked 69(p.cooked)
Cooking dislodges maximum residues.
Water wash removed maximum DDT residues whereas cooking is efficient to remove malathion and carbaryl residues.
Dikshit et al (1986)
Elkins et al (1968)
In the above table it could be mentioned that cooking is most successful to minimize the residues of diverse pesticides from a variety of vegetables even though in some circumstances washing with water was found to be successful to reduce the initial residues of pesticides and it has been identified that with all the ageing of residues or using the enhance in the sampling days over remedies the impact of washing decreases to eliminate the toxicant for the exact same extent as that of samples collected immediately right after spray where boiling or cooking is discovered to be efficient. One of many possible cause for higher percentage of removal of toxicant from right away collected samples as most of the residues are present in the surface of the samples and hence it really is very simple to eliminate by easy washing as observed by Dikshit et al (1984,86) Elkins et al (1968), Bhatia and Verma (1994) and Malik et al (1998). With the time elapsed the residues are migrated inside the deeper tissues or strongly adhere around the rough surface of some vegetables. In addition, the washing can't minimize the residues to the protected level as in comparison to boiling. You will find some research exactly where all of the three culinary processes proved to be inefficient to decrease the residues beneath the MRL value. According to Jacob and Verma (1991) residues of quinalphos in the treated cauliflower crop would be decreased only to some extent by various property processing approaches like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency of the residence processes for decontaminating the treated cabbage might be due to the robust adsorption properties of quinalphos and chlorpyriphos.
Impact of household preparation for decontamination of pesticide multiresidues in fruits and vegetables Low levels of pesticide residues have been detected in 97(40%) of mt 243 samples analyzed following following regular household washing, peeling and cooking procedures. The amount of samples containing detectable residues dropped to 47(19%) after household preparation. These results indicate that residue level in most commodities are substantially decreased soon after household preparation (Schattenberg et al., 1996) Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai local markets and fortified with known concentrations of various pesticides followed by decontamination study with different household preparations like washing, cooking , peeling resulting 65-95% decontamination of pesticide residues at various stages of 512 raw industry samples analyzed, the organochlorine and organophosphorus pesticides present in the 12 samples had been removed resulting in residues nicely under the toxicologically acceptable limits. A brief rinse in tap water reduces pesticide residues on a lot of sorts of produce (Krol et al., 2000). Rinsing removed residues for nine on the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos weren't removed. This study confirms that the water solubility of pesticides doesn't play a substantial function within the observed decrease. The majority of pesticide residues appear to reside on the surface of generate exactly where it really is removed by the mechanical action of rinsing. Earlier research of the effects of industrial and home preparation on pesticide residue in fruits and vegetables were summarized by Zabik (1987). The early studies showed residue reduction to become substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for industrial preparation and from 14 to 99+ % for house preparation with all the exception of parathion in spinach and broccoli, commercvial and house prewparation substantially lowered organophosphate residues, with the reduction typically getting within the higher 80 or 90% variety. Carbamate residues have been decreased by 58 to 99+ % when the vegetables had been commercially processed but only by 11 to 92% in home preparation. A current study in Korea supports these earlier studies (Lee and Lee, 1997). These authors located that 45% of the organophosphate residues have been eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.
Methods of multiresidue analysis of pesticides in fruits and vegetables Analysis by gas chromatography
Nakamura et al (1994) created a strategy for multiresidue analysis of 48 pesticides (20 organophosphorus, 7 organochlorine, 14 organonitrogen and 7 pyrethroid pesticides ) permitted in Japan around the basis of capillary GC after extracting the pesticides with nacetone from vegetable and fruit samples or with acetonitrile from lipid containing crops followed by reextraction into ethyl acetate (test solution). Organophosphorus pesticides were straight determined by GC-FPD. Organonitrogen pesticides were determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides were measured by GC-ECD right after clean up by florisil column chromatography. Recoveries for ten crops at fortification levels of 0.05-0.25 ppm had been 42.5-128.5%. the detection limits have been 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.
A multiresidue technique was employed by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which were extracted with acetone followed by liquid-liquid partitioning with water:apolar pesticides in petroleum ether phase, polar pesticides extracted from aqueous layer with dichloromethane and analyzed by gas chromatography with electron capture (GC-ECD), flame photometric (GC-FPD) and thermoionic specific (GC-TSD) detection.
The strategy used for multiresidue determination of 52 pesticides such as organophosphorus, organochlorine, organonitrogen, particular pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) using gas chromatography. Samples were extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates had been digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which can be collected in an ethanolic remedy of copper acetate and diethanolamine to form a yellow complex. The absorbance of yellow solution was determined spectrophotometrically at 435 nm. The average recoveries and CVs of the 52 pesticides had been 72-118 and 1-20%, respectively in the spiking levels of 0.01-1 ppm. A equivalent sort of technique was also described by Kole et al (1998).
Krol et al (2000) utilized a multiresidue procedure for determination of 12 pesticides in vegetables exactly where samples had been extracted with two propanol and petroleum ether followed by washing with distilled water three instances. Final analysis of the samples was performed by GC-ECD, FPD, XSD and/or ELCD.
Ramesah and Balasubramanian (1999) described a strategy to decide organochlorine, organonitrogen and organophosphorus pesticides in vegetables and fruits following extraction with 2-propanol and petroleum ether by mechanical shaker followed by partitioning with distilled water and column cleanup more than florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was accomplished with acetone followed by partitioning with 10%NaCl and ethyl acetate and column clean up over silica gel. organochlorine, organophosphorus and organonitrogen compounds were analyzed by GC-ECD,GC-FPD and GC-NPD, respectively.
Using GC-ECD, the efficiencies of acetonitrile and acetone to extract the 8 pyrethroids from 6 fruits and vegetable samples were compared by Pang et al (1997). The extraction efficiency of acetone was competitive with that of acetonitrile for the six fruit and vegetable samples. The ruggedness tests demonstrated additional that the proposed method is easy, accurate with very good precision and suitable for multiresidue evaluation of pyrethroid in different agricultural merchandise.
Organophosphorus and organochlorine pesticide residues from fruit and vegetables by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) in the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in selected ion monitoring (SIM) mode were determined by Torres et al (1995) following extraction by Matrix Solid Phase Dispersion (MSPD) resulting recoveries of 41-108% with relative SD of 2-14% in the conc. range 0.5-10 g/liter in oranges, lemons, grapefruit, pears, plums, lettuces and tomatoes. A multiresidue technique as described by Sannino et al (1995) for quantitative determination of 39 organophosphorus compounds (parent pesticides and their main metabolites) in 7 fatty processed foods based on automated gel permeation chromatography with a Biobeads SX3 column along with a methylene chloride-cyclohexane (15 + 85) eluant soon after extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD using OV-1701 and DB-5 columns. Typical recoveries from samples fortified at 0.025-1 mg/kg ranged from 50.6% for dichlorvos to 185% for malaoxon. Determination limits were amongst 0.005 and 0.040 mug/mL. Outcomes were confirmed by gas chromatography/mass spectrometry with selected-ion monitoring. Gas chromatographic conditions for separation and identification on the compounds had been chosen employing two capillary columns of distinct polarities and two detectors, ECD and NPD for multiresidue quantitative determination of 37 pesticides in fruit and vegetables and to study the efficiency of gel-permeation chromatography clean-up soon after ethyl acetate extraction (Balinova,1999). Trova et al (1999) performed liquid chromatographic determination of pesticide residues (like azinphos-ethyl, azinphos-methyl, carbaryl, diflubenzuron, dinocap and teflubenzuron) in vegetables soon after extraction utilizing an ethyl acetate/n-hexane solvent system rather from the extensively employed methylene chloride. Recoveries as essential by 'Guidelines for residues monitoring in the European Union' were observed; the new solvent method could possibly be regarded as as an alternative to halogenated compounds, hazardous for their toxicity and harmful for their environmental behaviors, in extraction of HPLC-determinable active compounds. A wide variety screening method was proposed by Gelsomino et al (1997) for multiresidue evaluation of 77 pesticides (12 organohalogens, 45 organonitrogens, 11 organophosphorus and 9 pyrethroids) in agricultural merchandise employing gas chromatography equipped with long, narrow-bore fused-silica open-tubular columns and electron-capture detector (ECD). Residues were extracted with acetone followed by dichloromethane partitioning and gel permeation chromatographic clean up. Recoveries in the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.ten mg/kg had been 70-108%. Limits of detection were significantly less than 0.01 mg/kg for ECD. Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical technique employing GC-ECD and GC-NPD systems with capillary columns. Ueno et al (2003) studied an effective and reputable multiresidue technique for figuring out 52 nitrogen- and/or phosphorus- containing pesticide residues within a large number of vegetable samples in which samples have been extracted with acetonitrile, as well as the separated acetonitrile layer was purified by gel permeation chromatography that divided the pesticide eluate into two fractoions, the pesticide fractions had been respectively purified by a 2-step minicolumn cleanup, the second fraction via silica gel minicolumn; very first fraction via the tandem minicolumn (florisil minicolumn, inserted on silica gel minicolumn) which was eluted with acetone-petroleum ether (3+7). The combined eluate was subjected to dual column gas chromatography with nitrogen-phosphorus and flame photometric detection. Recoveries of 52 pesticides from fortified samples ranged from 72 to 108% with relative normal deviations of 2-17%, except for the recoveries of methamidophos and chorothalonil. The detection limits on the pesticides had been satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables. Menkissoglu et al (2004) performed a study on the matrix induced effect for 16 typical pesticides, most often discovered in monitoring research in tomato pepper and cucumber, employing a simple multiresidue technique with GC-ECD or NPD, without a preceding cleanup step. Anomalously higher GC responses and subsequently extremely higher recoveries for numerous pesticides in the extracts were obtained by a standard calibration with pesticide resolution in ethyl acetate. A quicker, significantly less efficient, environmentally safer supercritical fluid extraction (SFE) method was evaluated by Garcia et al (1996) over conventional sonvent extraction methods for the extraction of imidacloprid, methiocarb, chlorpyrifos, chlorothalonil, endosulfan-1, endosulfan-2 and endosulfan sulfate, from pepper and tomato employing vegetable sample: anhydrous magnesium sulfate (five:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for evaluation. The selected SFE conditions had been 300 atm, 500C, 200l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in three ml of ethyl acetate. Except for imidacloprid, which was not recovered beneath any from the assessed circumstances, pesticide recoveries had been higher than 80%. A simplified technique is described by Chaput (1987) exactly where reverse phase liquid chromatography was utilized with post column derivatisation and fluorescence detector to establish 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl and propoxur) and three associated metabolites in fruits and vegetables right after extraction from the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with higher chlorophyll and/or carotene content material (e.g. cabbage and broccoli). Recovery information had been obtained by fortifying five diverse crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.5 ppm. Recoveries averaged 93% at each fortification levels. The coefficient of variation in the strategy at each levels is
Estimation by GC-MS/LC-MS Since the mass spectrometer is capable of reaching higher levels of molecular specificity as in comparison with the standard GC detectors and may be programmed to look for many hundred target ions, GC/MS could be a promising technique for regulatory agencies to discover for monitoring pesticide residues in daily meals provide (Cheng et al, 1994). Cheng et al (1994) reported a multiresidue approach utilizing gas chromatography /mass spectrometry/selected ion monitoring (GC/MS/SIM) for the determination of captan, chlorothalonil, dichlorovos, dimethoate, EPN, phorate, primiphos-methyl and prothiophos residues in fruits and vegetables. Recoveries had been in between 46 and 108% in the 0.five mg/kg fortification amount of each and every pesticide in apples, cabbages, cucumbers and grapes. Coefficients of variation have been among 0.7 and 19%, with an average of 7.5%. The estimated limits of detection in the pesticides within the crops were 0.1-0.05 mg/kg, except that captan had limit of detection in the crops larger than 0.5 mg/kg. A method according to solid-phase extraction using a carbograph 1 cartridge and reverse phase liquid chromatography /mass spectrometry (LC/MS) with an electrospray (ES) interface was described by Corcia et al (1996) for measuring traces of N-methylcarbamate insecticides in ten various types of fruits and vegetables .twelve carbamates added to vegetable materials had been extracted with methanol employing a homogenizer followed by filtration , an aliquot in the homogenate equivalent to five g in the vegetable material was suitably diluted with water and passed by way of a 1 Carbograpg 1 extraction cartridge. Carbamates were eluted by passing by way of the cartridge six ml of a CH2Cl2/CH3OH (80:20 v/vegetables) mixture. Recovery of the analytes was much better than 80%, irrespective from the type vegetable matrix to which the analytes were added. A approach making use of completely automated solid-phase extraction (SPE) sample cleanup and on-line liquid chromatographic analysis with UV and fluorescence detection in tandem for determination of carbendazim and thiabendazole in different crops was reported by Hiemstra et al (1995). A total of 199 pesticides were determined by Fillion et al (1995) in fruits and vegetables using acetonitrile as extracting solvent as well as a miniaturized charcoal-celite column cleanup followed by gas chromatography with mass-selective detection in selective-ion monitoring mode. Carbamates had been analyzed by liquid chromatography with post column reaction and fluorescence detection. Recovery information had been obtained by fortifying 3 matrixes (pear, carrots and bananas) at 0.1-0.five ppm. Blasco et al (2004) utilized a quantitative matrix solid-phase dispersion and liquid chromatographyatmospheric stress chemical ionization mass spectrometry (LC-APCI-MS) strategy for the simultaneous evaluation of dithiocarbamates and their degradation merchandise in crops. Typical recoveries varied from 33 to 109%, and relative common deviation was amongst 4 and 21% with limits of quantification ranged from 0.25 to two.5 mg/kg. A multiresidue analysis for the determination of the 101 pesticides, like organophosphorus, organochlorine and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector was performed by Chun et al (2003). Analysis was performed within the selected-ion monitoring mode. Samples have been spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% from the pesticides wee among 70 and 110%; however, the recoveries of acephate and folpet were very poor, i.e.,
Proposed strategy of operate Standardisation of multiresidue analytical techniques of pesticides
Analytical common of chosen pesticides belonging to various classes viz. OC (HCH (?,?,? and ? isomer), DDT (OP-DDT, PP-DDT, op-DDD, pp-DDE), Endosulfan (?,? and endosulfan sulfate) and dicofol);OP(Dimethoate, Malathion, Methyl parathion, Chlorpyriphos, Quinalphos, Triazophos, Phosphamidon,Dichlorvos Metasystox and Monocrotophos) and Synthetic Pyrethroids (Cypermethrin, Deltamethrin, Fenvalerate) for monitoring and decontamination research happen to be collected from various sources as follows: Sl No.Name of the pesticidesPurity %Source Organochlorine 1?-HCH99.5EPA two?-HCH99.5EPA three?-HCH99.5EPA 4?-HCH99.5EPA 5OP-DDT99.7EPA 6PP-DDT99.7EPA 7OP-DDD99.7EPA 8PP-DDE99.7EPA 9?-endosulfan99.0Excel 10?-endosulfan99.0Excel 11endosulfan sulfate99.0Excel 12Dicofol96.0Bayer Organophosphorus 13Dimethoate96.5UPL 14Malathion97.3UPL 15Methyl parathion98.5Bayer 16Chlorpyriphos99.7Denocil crop protection Ltd. 17Quinalphos95.6Sandoz Ltd. 18Phosphamidon93.9Bayer 19Triazophos40.8Aventis Crop Science 20Monocrotophos77.0UPL 21Dichlorvos- 22Metasystox- Synthetit pyrethroids CCSRI Cypermethrin,99.0CCSRI Deltamethrin
Fenvalerate99.0
99.0CCSRI
four.1.1Stock standard solution: Stock common remedy of various pesticides are to be ready in distilled hexane/acetone and diluted suitably to serve as operating normal and to check the mindividual chromatographic peaks for their suitability for multiresidue evaluation. four.1.2Preparation of mixed regular solytion: in the person regular solutions a mixed standard remedy is always to be ready for strategy mdevelopment and decontamination research. four.1.3Extraction and cleanup From the evaluation of literature 3 strategies proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) have been selected to conduct the extraction and cleanup process exactly where each the liquid-liquid as well as a solid-phase extraction with a cartridge column will likely be in comparison with create a quick,simpler and cost-effective approach to screen a wide range of pesticides. 4.1.4Estimation of pesticide multiresidue A gas chromatograph coupled with an Electron Capture Detectore (ECD) and Nitrogen Phosphorus Detector (NPD) would be to be utilised for estimation in the pesticide residues. The operating situations may also be studied as stated within the selected 3 approaches. four.1.5standardisation in the mathod: The chosen technique wil be standardized by conducting a recovery study with the mixed regular by spiking in the fruits and vegetables. 4.2Monitoring of pesticide residues: 4.two.1Sampling programme: Typa of sample: fruits (Mango and Banana) and vegetables (Tomato, Chilli, Caulioflower, Cabbage). Sampling location: From 2 reputed wholesale markets like.. of West Bengal. Frequency and duration of sampling: After in each and every month for a single year. Volume of sample: 1 kg of every single sample. 4.2.2pesticide residues to be monitored: All the pesticides listed in table two. four.3Decontamination studies The pesticides are to be selected on the basis of their greater use pattern in W.B. the sa]elected pesticides are listed as follows: OC (?-endosulfan, ?-endosulfan endosulfan sulfate, dicofol OP: Chlorpyriphos, Quinalphos, Dimethoate, Triazophos, Malathion, Methyl parathion, phosphamidon, monocrotophos, metasystix; Synthetic pyrethroids: Cypermethrin, Deltamethrin and Fenvalerate. four.3.1Decontamination processes to become followed: 4.3.1.1Washing with water: Chopped samples will probably be taken inside a tray containing water as well as the material will probably be gently rubbed with water for about one minute and also the water will be decanted or it really is rinsed under running tap water for 130 sec., with gentle rotation by hand . washing is to be repeated twice or thrice. four.three.1.2Salt water washing: Chopped samples is going to be dipped in a beaker containing 2% or 55 sodium chloride answer. After 10-15 minutes the plant samplws will probably be gently rubbed by hand in salt solution and salt water will probably be decanted. Then the samples will likely be washed in water. 4.three.1.three Boiling/Cooking: Unwashed samples wil be chopped and boiled within a beaker till the water is fully evaporated covering the containr with or with out lid. Samples is usually to be allowed to cool. 4.three.1.4 Combination from the above strategies like soak in water for 15 min., rinse with water, reduce into pieces and boiled in water 4.three.1.5Wash with soap solution, rinse with water.
The effect of household preparation or commercial processing to minimize the pesticide residue levels on raw agricultural commodities (RACs) is significant as they normally decline the residues. These types of processung strudies are intended: To provide info around the transfer of residues in the RAC for the processed products, in an effort to calculate reduction factor or concentration variables; To allow and more realistic estimate to be produced in the dietary intake of pesticide residues; To establish MRLs for residues in processed goods exactly where necessary, in line with requirements of national regulatory authorities or international standards. Preferably, RAC samples utilised in processing research need to include field treated quantifiable residues as close as possible for the MRL, so that measurable residues are obtained, and transfer variables for the various processed commodities could be determined. A transfer aspect gives the ratio in the residue concentration inside the processed commodity to that in the RAC. For instance when the residue concentration is 0.five mg/kg in olives and 0.2 mg/kg in olive oil, the transfer issue is 0.2/0.5=0.four. A issue 1 (= concentration aspect) indicates a concentration impact from the processing procedures. Enhancing the residues either by increasing the application rates, shortening the pre-harvest interval (PHI) or spiking the RAC together with the active ingredient and its metabolites in vitro is not, as and rule, desirable. Spiking is only acceptable if the RAC residues may be shown to consist only of surface residues. However, in some cases, specifically exactly where residues inside the RAC are close for the analytical limit of determination, field therapy at exaggerated rates or shortened PHIs is advisable to obtain adequate residue levels for the processing research.
The initial step in household or commercial meals processing would be the preparation of meals making use of numerous mechanical processes, such as removing broken or soiled things or components of crops, washing, peeling, trimming or hulling. This often leads to important declines in the volume of pesticide residues inside the remaining edible portions (Petersen et al., 1996; Celik et al., 1995; Schattenberg et al., 1996).
WASHING
Household washing procedures are usually carried out with operating or standing water at moderate temperatures. Detergents, chlorine or ozone might be added for the wash water to enhance the effectiveness from the washing process (Ong et al., 1996). If necessary, several washing methods can be conducted consequently. The effects rely on the physiochemical properties of the pesticides, like water solubility, hydrolytic rate continual, volatility and octanol-water partition coefficient (Pow), in conjunction together with the actual physical location in the residues; washing processes cause reduction of hydrophilic residues which are located on the surface of the crops. In addition, the temperature from the washing water along with the type of washing has an influence on the residue level. As pointed out by Holland et al. (1994), hot washing as well as the addition of detergents are far more effective than cold water washing. Washing coupled with gentle rubbing by hand below tap water for 1 min dislodges pesticide residues considerably (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues are not removed significantly by washing. Table (1) shows examples from the effects of washing around the residue levels of distinct pesticides applied to fruits and vegetables.
PEELING
The outer leaves of vegetables often include residues of pesticides applied throughout the expanding season. As a result, peeling or trimming procedures reduce the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables using a knife is frequent household practice. Many examples show that most of the residues concentration is positioned in or on the peel. Peeling on the RACs may remove greater than 50% from the pesticide residues present within the commodity. As a result, removal of the peel achieves practically comprehensive removal of residues, so leaving tiny inside the edible portions. This is specially essential for fruits that are not eaten with their peels, for example bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot decreased the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer issue of 0.two. Nonetheless, the peel from commercial peeling processes may be used as animal feed or for the production of crucial oils (citrus) or pectin (citrus, apple etc.). For such industrial processes, it is important to recognize that especially non-systemic surface residues are typically concentrated within the peel. For systemic pesticides, peeling may not be as successful as shown by Sheikhorgan et al (1994). Soon after application of thiometon on cucumbers, no reduction of residue levels might be detected within the peeled cucumbers. Under the Codex Alimentarius, as in other international requirements, MRLs refer towards the entire fruits, which can be suitable for assessing compliance with GAP. These MRLs are of restricted significance, nevertheless, in assessing dietary exposure to pesticides from fresh fruits, that are peeled (Holland et al.,1994).
COOKING Cooking procedures at diverse temperatures, the duration on the procedure, the amount of water or food additives, as well as the variety of method (open or closed) may have an effect around the residue level. Usually, residues are decreased during the cooking process by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Many studies had been reported on the dissipation of pesticides in crops throughout cooking. Furthermore for the research summarized in table 1 the behavior on the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos during cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased during the cooking method corresponding for the boiling time. Based on their water solubility, some pesticides have been translocated from the raw supplies into the cooking water. However, the pesticide remained within the processed meals based on their octanol-water partition coefficient, which can be an indicator of hydrophilic or lipophilic properties of the compound. In exceptional instances, cooking processes could trigger pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), which is a lot far more potent than the parent compound (Leparulo-Lofus et al.,1992). Another instance may be the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, throughout heating processes (Petersen et al., 1996).
Dipping in chemical answer Sodium chloride answer is largely employed to decontaminate the pesticide residues from different fruits and vegetables .there are many studies to prove the efficacy of salt water washing to dislodge the pesticides from crops. In this method, sample of chopped fruits and vegetables is place in a beaker containing 5% sodium chloride remedy. After 15 minutes the plant samples are gently rubbed by hand in salt remedy and alt water is decanted. The examples on the effect of salt resolution therapy on the residue levels of various pesticides applied to vegetables happen to be shown in table 1. Kumar et al (2000) reported that dipping of green chillies in 2% salt answer for ten minute followed by water wash prove to be efficient, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and five days right after spray of triazophos (700g a.i./ha) while the acephate residues have been removed to an extent of 78.95% at zero day. Following same approach Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and five days right after spraying of cypermethrin in chillies. Dip therapy of fruits in NaCl resolution, HCl, acetic acid, NaOH remedy, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids in comparison with 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b). Water remedy of NaOH, acetic acid potassium dichromate and soap answer utilized as decontaminating agents for tom . The therapy of fruits with 2% tamarind resolution dip for 5 minute followed by tap water wash and steam cooking for ten min. was located to take away the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, 100 and 100% respectively. Remedy with 2% salt resolution was equally powerful. Dip treatments in the brinjal fruit wioth water, sodium chloride, HCl remedy, acetic acid resolution or potassium permanganate resolution had been all identified to eliminate 30-33% on the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH remedy 40-45% and Teepol (a detergent) resolution 50-60%. The impact of washing in decreasing the residues decreased progressively at the second and third harvests. Several experiments had been carried out with the three typical household preparations viz. washing with water, salt water washing and cooking to asses their relative efficiencies in minimizing the pesticide residues in different vegetables. The outcomes happen to be summarized in the following table.
Table: Impact of washing, salt water washing and cooking on pesticide residue levels.
Crop Pesticide % of Residue dislodged *ResultReference Washing with waterSalt water washing Cooking CauliflowerMethamidophos41-4846-4746.94 -53.54Largest reduction was brought about by cooking. Jacob and Verma (1990)
Okra Methamidophos 64-72 19-58 58-64Washing with water could get rid of maximum residues indicating its maximum solubility in water even though all the processes reduce down the TMRL values.Jacob and Verma (1990)
CauliflowerAlpha-cypermethrin 7-38_ 12-17Washing was discovered to be a lot more efficient than cooking probably due to the thermal stability of cypermethrin.Malik et al (1997)
Cabbage
Chlorpyriphos
Quinalphos
38
41
52.13
56.50
54.3
55With the 3 processes residues were decreased to some extent. They could not minimize the residue beneath the MRL. Therefore a waiting period of a minimum of 1 and two weeks, respectively, was recommended irrespective of washing cooking for quinalphos and chlorpyriphos on cabbage. Nagesh and Verma (1997)
Cow pea Metasystox
Carbalyl 84.three
87.5 86.4
88.7 83.4
80.8Only boiling from the pod samples could decontaminate the residues present of surface or inside the tissue towards the extent of protected limits by 10th day of treatment.Dikshit et al (1984)
Cauliflower Malathion 60 70 80Cooking was located to become most powerful and lowered the TMRL worth from one particular week to zero days.Jacob and Verma (1989)
Bhindi Quinalphos 61.84-64.35 43-53 78-82 Each washing with water and salt water washing brought down the residues below the MRL at zero days, cooking also did this resulting maximum reduction of residues. Jacob and Verma (1985)
Cabbage Malathion
Carbaryl
Pyrethroids 64.60
75.40
22.06 (av.) -
-
-
83.97
89.62
56.72 (av.) The extent of decontamination was greater due to cooking in comparison with washing for all insecticides. Bhatia and Verma (1994) Leaves and curds of cauliflower heads of cabbage and pods of Indian colza
Green beans
Methamidophos
DDT
Malathion
Carbaryl
65.71-77.67
71
96
52
-
-
-
-
80-88.88
52(cooked) 66 (pressure cooked)
99(cooked) 99(p.cooked)
77cooked 69(p.cooked)
Cooking dislodges maximum residues.
Water wash removed maximum DDT residues whereas cooking is efficient to remove malathion and carbaryl residues.
Dikshit et al (1986)
Elkins et al (1968)
In the above table it could be mentioned that cooking is most successful to minimize the residues of diverse pesticides from a variety of vegetables even though in some circumstances washing with water was found to be successful to reduce the initial residues of pesticides and it has been identified that with all the ageing of residues or using the enhance in the sampling days over remedies the impact of washing decreases to eliminate the toxicant for the exact same extent as that of samples collected immediately right after spray where boiling or cooking is discovered to be efficient. One of many possible cause for higher percentage of removal of toxicant from right away collected samples as most of the residues are present in the surface of the samples and hence it really is very simple to eliminate by easy washing as observed by Dikshit et al (1984,86) Elkins et al (1968), Bhatia and Verma (1994) and Malik et al (1998). With the time elapsed the residues are migrated inside the deeper tissues or strongly adhere around the rough surface of some vegetables. In addition, the washing can't minimize the residues to the protected level as in comparison to boiling. You will find some research exactly where all of the three culinary processes proved to be inefficient to decrease the residues beneath the MRL value. According to Jacob and Verma (1991) residues of quinalphos in the treated cauliflower crop would be decreased only to some extent by various property processing approaches like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency of the residence processes for decontaminating the treated cabbage might be due to the robust adsorption properties of quinalphos and chlorpyriphos.
Impact of household preparation for decontamination of pesticide multiresidues in fruits and vegetables Low levels of pesticide residues have been detected in 97(40%) of mt 243 samples analyzed following following regular household washing, peeling and cooking procedures. The amount of samples containing detectable residues dropped to 47(19%) after household preparation. These results indicate that residue level in most commodities are substantially decreased soon after household preparation (Schattenberg et al., 1996) Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai local markets and fortified with known concentrations of various pesticides followed by decontamination study with different household preparations like washing, cooking , peeling resulting 65-95% decontamination of pesticide residues at various stages of 512 raw industry samples analyzed, the organochlorine and organophosphorus pesticides present in the 12 samples had been removed resulting in residues nicely under the toxicologically acceptable limits. A brief rinse in tap water reduces pesticide residues on a lot of sorts of produce (Krol et al., 2000). Rinsing removed residues for nine on the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos weren't removed. This study confirms that the water solubility of pesticides doesn't play a substantial function within the observed decrease. The majority of pesticide residues appear to reside on the surface of generate exactly where it really is removed by the mechanical action of rinsing. Earlier research of the effects of industrial and home preparation on pesticide residue in fruits and vegetables were summarized by Zabik (1987). The early studies showed residue reduction to become substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for industrial preparation and from 14 to 99+ % for house preparation with all the exception of parathion in spinach and broccoli, commercvial and house prewparation substantially lowered organophosphate residues, with the reduction typically getting within the higher 80 or 90% variety. Carbamate residues have been decreased by 58 to 99+ % when the vegetables had been commercially processed but only by 11 to 92% in home preparation. A current study in Korea supports these earlier studies (Lee and Lee, 1997). These authors located that 45% of the organophosphate residues have been eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.
Methods of multiresidue analysis of pesticides in fruits and vegetables Analysis by gas chromatography
Nakamura et al (1994) created a strategy for multiresidue analysis of 48 pesticides (20 organophosphorus, 7 organochlorine, 14 organonitrogen and 7 pyrethroid pesticides ) permitted in Japan around the basis of capillary GC after extracting the pesticides with nacetone from vegetable and fruit samples or with acetonitrile from lipid containing crops followed by reextraction into ethyl acetate (test solution). Organophosphorus pesticides were straight determined by GC-FPD. Organonitrogen pesticides were determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides were measured by GC-ECD right after clean up by florisil column chromatography. Recoveries for ten crops at fortification levels of 0.05-0.25 ppm had been 42.5-128.5%. the detection limits have been 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.
A multiresidue technique was employed by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which were extracted with acetone followed by liquid-liquid partitioning with water:apolar pesticides in petroleum ether phase, polar pesticides extracted from aqueous layer with dichloromethane and analyzed by gas chromatography with electron capture (GC-ECD), flame photometric (GC-FPD) and thermoionic specific (GC-TSD) detection.
The strategy used for multiresidue determination of 52 pesticides such as organophosphorus, organochlorine, organonitrogen, particular pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) using gas chromatography. Samples were extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates had been digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which can be collected in an ethanolic remedy of copper acetate and diethanolamine to form a yellow complex. The absorbance of yellow solution was determined spectrophotometrically at 435 nm. The average recoveries and CVs of the 52 pesticides had been 72-118 and 1-20%, respectively in the spiking levels of 0.01-1 ppm. A equivalent sort of technique was also described by Kole et al (1998).
Krol et al (2000) utilized a multiresidue procedure for determination of 12 pesticides in vegetables exactly where samples had been extracted with two propanol and petroleum ether followed by washing with distilled water three instances. Final analysis of the samples was performed by GC-ECD, FPD, XSD and/or ELCD.
Ramesah and Balasubramanian (1999) described a strategy to decide organochlorine, organonitrogen and organophosphorus pesticides in vegetables and fruits following extraction with 2-propanol and petroleum ether by mechanical shaker followed by partitioning with distilled water and column cleanup more than florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was accomplished with acetone followed by partitioning with 10%NaCl and ethyl acetate and column clean up over silica gel. organochlorine, organophosphorus and organonitrogen compounds were analyzed by GC-ECD,GC-FPD and GC-NPD, respectively.
Using GC-ECD, the efficiencies of acetonitrile and acetone to extract the 8 pyrethroids from 6 fruits and vegetable samples were compared by Pang et al (1997). The extraction efficiency of acetone was competitive with that of acetonitrile for the six fruit and vegetable samples. The ruggedness tests demonstrated additional that the proposed method is easy, accurate with very good precision and suitable for multiresidue evaluation of pyrethroid in different agricultural merchandise.
Organophosphorus and organochlorine pesticide residues from fruit and vegetables by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) in the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in selected ion monitoring (SIM) mode were determined by Torres et al (1995) following extraction by Matrix Solid Phase Dispersion (MSPD) resulting recoveries of 41-108% with relative SD of 2-14% in the conc. range 0.5-10 g/liter in oranges, lemons, grapefruit, pears, plums, lettuces and tomatoes. A multiresidue technique as described by Sannino et al (1995) for quantitative determination of 39 organophosphorus compounds (parent pesticides and their main metabolites) in 7 fatty processed foods based on automated gel permeation chromatography with a Biobeads SX3 column along with a methylene chloride-cyclohexane (15 + 85) eluant soon after extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD using OV-1701 and DB-5 columns. Typical recoveries from samples fortified at 0.025-1 mg/kg ranged from 50.6% for dichlorvos to 185% for malaoxon. Determination limits were amongst 0.005 and 0.040 mug/mL. Outcomes were confirmed by gas chromatography/mass spectrometry with selected-ion monitoring. Gas chromatographic conditions for separation and identification on the compounds had been chosen employing two capillary columns of distinct polarities and two detectors, ECD and NPD for multiresidue quantitative determination of 37 pesticides in fruit and vegetables and to study the efficiency of gel-permeation chromatography clean-up soon after ethyl acetate extraction (Balinova,1999). Trova et al (1999) performed liquid chromatographic determination of pesticide residues (like azinphos-ethyl, azinphos-methyl, carbaryl, diflubenzuron, dinocap and teflubenzuron) in vegetables soon after extraction utilizing an ethyl acetate/n-hexane solvent system rather from the extensively employed methylene chloride. Recoveries as essential by 'Guidelines for residues monitoring in the European Union' were observed; the new solvent method could possibly be regarded as as an alternative to halogenated compounds, hazardous for their toxicity and harmful for their environmental behaviors, in extraction of HPLC-determinable active compounds. A wide variety screening method was proposed by Gelsomino et al (1997) for multiresidue evaluation of 77 pesticides (12 organohalogens, 45 organonitrogens, 11 organophosphorus and 9 pyrethroids) in agricultural merchandise employing gas chromatography equipped with long, narrow-bore fused-silica open-tubular columns and electron-capture detector (ECD). Residues were extracted with acetone followed by dichloromethane partitioning and gel permeation chromatographic clean up. Recoveries in the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.ten mg/kg had been 70-108%. Limits of detection were significantly less than 0.01 mg/kg for ECD. Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical technique employing GC-ECD and GC-NPD systems with capillary columns. Ueno et al (2003) studied an effective and reputable multiresidue technique for figuring out 52 nitrogen- and/or phosphorus- containing pesticide residues within a large number of vegetable samples in which samples have been extracted with acetonitrile, as well as the separated acetonitrile layer was purified by gel permeation chromatography that divided the pesticide eluate into two fractoions, the pesticide fractions had been respectively purified by a 2-step minicolumn cleanup, the second fraction via silica gel minicolumn; very first fraction via the tandem minicolumn (florisil minicolumn, inserted on silica gel minicolumn) which was eluted with acetone-petroleum ether (3+7). The combined eluate was subjected to dual column gas chromatography with nitrogen-phosphorus and flame photometric detection. Recoveries of 52 pesticides from fortified samples ranged from 72 to 108% with relative normal deviations of 2-17%, except for the recoveries of methamidophos and chorothalonil. The detection limits on the pesticides had been satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables. Menkissoglu et al (2004) performed a study on the matrix induced effect for 16 typical pesticides, most often discovered in monitoring research in tomato pepper and cucumber, employing a simple multiresidue technique with GC-ECD or NPD, without a preceding cleanup step. Anomalously higher GC responses and subsequently extremely higher recoveries for numerous pesticides in the extracts were obtained by a standard calibration with pesticide resolution in ethyl acetate. A quicker, significantly less efficient, environmentally safer supercritical fluid extraction (SFE) method was evaluated by Garcia et al (1996) over conventional sonvent extraction methods for the extraction of imidacloprid, methiocarb, chlorpyrifos, chlorothalonil, endosulfan-1, endosulfan-2 and endosulfan sulfate, from pepper and tomato employing vegetable sample: anhydrous magnesium sulfate (five:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for evaluation. The selected SFE conditions had been 300 atm, 500C, 200l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in three ml of ethyl acetate. Except for imidacloprid, which was not recovered beneath any from the assessed circumstances, pesticide recoveries had been higher than 80%. A simplified technique is described by Chaput (1987) exactly where reverse phase liquid chromatography was utilized with post column derivatisation and fluorescence detector to establish 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl and propoxur) and three associated metabolites in fruits and vegetables right after extraction from the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with higher chlorophyll and/or carotene content material (e.g. cabbage and broccoli). Recovery information had been obtained by fortifying five diverse crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.5 ppm. Recoveries averaged 93% at each fortification levels. The coefficient of variation in the strategy at each levels is
Estimation by GC-MS/LC-MS Since the mass spectrometer is capable of reaching higher levels of molecular specificity as in comparison with the standard GC detectors and may be programmed to look for many hundred target ions, GC/MS could be a promising technique for regulatory agencies to discover for monitoring pesticide residues in daily meals provide (Cheng et al, 1994). Cheng et al (1994) reported a multiresidue approach utilizing gas chromatography /mass spectrometry/selected ion monitoring (GC/MS/SIM) for the determination of captan, chlorothalonil, dichlorovos, dimethoate, EPN, phorate, primiphos-methyl and prothiophos residues in fruits and vegetables. Recoveries had been in between 46 and 108% in the 0.five mg/kg fortification amount of each and every pesticide in apples, cabbages, cucumbers and grapes. Coefficients of variation have been among 0.7 and 19%, with an average of 7.5%. The estimated limits of detection in the pesticides within the crops were 0.1-0.05 mg/kg, except that captan had limit of detection in the crops larger than 0.5 mg/kg. A method according to solid-phase extraction using a carbograph 1 cartridge and reverse phase liquid chromatography /mass spectrometry (LC/MS) with an electrospray (ES) interface was described by Corcia et al (1996) for measuring traces of N-methylcarbamate insecticides in ten various types of fruits and vegetables .twelve carbamates added to vegetable materials had been extracted with methanol employing a homogenizer followed by filtration , an aliquot in the homogenate equivalent to five g in the vegetable material was suitably diluted with water and passed by way of a 1 Carbograpg 1 extraction cartridge. Carbamates were eluted by passing by way of the cartridge six ml of a CH2Cl2/CH3OH (80:20 v/vegetables) mixture. Recovery of the analytes was much better than 80%, irrespective from the type vegetable matrix to which the analytes were added. A approach making use of completely automated solid-phase extraction (SPE) sample cleanup and on-line liquid chromatographic analysis with UV and fluorescence detection in tandem for determination of carbendazim and thiabendazole in different crops was reported by Hiemstra et al (1995). A total of 199 pesticides were determined by Fillion et al (1995) in fruits and vegetables using acetonitrile as extracting solvent as well as a miniaturized charcoal-celite column cleanup followed by gas chromatography with mass-selective detection in selective-ion monitoring mode. Carbamates had been analyzed by liquid chromatography with post column reaction and fluorescence detection. Recovery information had been obtained by fortifying 3 matrixes (pear, carrots and bananas) at 0.1-0.five ppm. Blasco et al (2004) utilized a quantitative matrix solid-phase dispersion and liquid chromatographyatmospheric stress chemical ionization mass spectrometry (LC-APCI-MS) strategy for the simultaneous evaluation of dithiocarbamates and their degradation merchandise in crops. Typical recoveries varied from 33 to 109%, and relative common deviation was amongst 4 and 21% with limits of quantification ranged from 0.25 to two.5 mg/kg. A multiresidue analysis for the determination of the 101 pesticides, like organophosphorus, organochlorine and nitrogen-containing pesticides, in crops by gas chromatography with mass selective detector was performed by Chun et al (2003). Analysis was performed within the selected-ion monitoring mode. Samples have been spiked with pesticides at 0.1-1.0 mg/kg. The recoveries of 90% from the pesticides wee among 70 and 110%; however, the recoveries of acephate and folpet were very poor, i.e.,
Proposed strategy of operate Standardisation of multiresidue analytical techniques of pesticides
Analytical common of chosen pesticides belonging to various classes viz. OC (HCH (?,?,? and ? isomer), DDT (OP-DDT, PP-DDT, op-DDD, pp-DDE), Endosulfan (?,? and endosulfan sulfate) and dicofol);OP(Dimethoate, Malathion, Methyl parathion, Chlorpyriphos, Quinalphos, Triazophos, Phosphamidon,Dichlorvos Metasystox and Monocrotophos) and Synthetic Pyrethroids (Cypermethrin, Deltamethrin, Fenvalerate) for monitoring and decontamination research happen to be collected from various sources as follows: Sl No.Name of the pesticidesPurity %Source Organochlorine 1?-HCH99.5EPA two?-HCH99.5EPA three?-HCH99.5EPA 4?-HCH99.5EPA 5OP-DDT99.7EPA 6PP-DDT99.7EPA 7OP-DDD99.7EPA 8PP-DDE99.7EPA 9?-endosulfan99.0Excel 10?-endosulfan99.0Excel 11endosulfan sulfate99.0Excel 12Dicofol96.0Bayer Organophosphorus 13Dimethoate96.5UPL 14Malathion97.3UPL 15Methyl parathion98.5Bayer 16Chlorpyriphos99.7Denocil crop protection Ltd. 17Quinalphos95.6Sandoz Ltd. 18Phosphamidon93.9Bayer 19Triazophos40.8Aventis Crop Science 20Monocrotophos77.0UPL 21Dichlorvos- 22Metasystox- Synthetit pyrethroids CCSRI Cypermethrin,99.0CCSRI Deltamethrin
Fenvalerate99.0
99.0CCSRI
four.1.1Stock standard solution: Stock common remedy of various pesticides are to be ready in distilled hexane/acetone and diluted suitably to serve as operating normal and to check the mindividual chromatographic peaks for their suitability for multiresidue evaluation. four.1.2Preparation of mixed regular solytion: in the person regular solutions a mixed standard remedy is always to be ready for strategy mdevelopment and decontamination research. four.1.3Extraction and cleanup From the evaluation of literature 3 strategies proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) have been selected to conduct the extraction and cleanup process exactly where each the liquid-liquid as well as a solid-phase extraction with a cartridge column will likely be in comparison with create a quick,simpler and cost-effective approach to screen a wide range of pesticides. 4.1.4Estimation of pesticide multiresidue A gas chromatograph coupled with an Electron Capture Detectore (ECD) and Nitrogen Phosphorus Detector (NPD) would be to be utilised for estimation in the pesticide residues. The operating situations may also be studied as stated within the selected 3 approaches. four.1.5standardisation in the mathod: The chosen technique wil be standardized by conducting a recovery study with the mixed regular by spiking in the fruits and vegetables. 4.2Monitoring of pesticide residues: 4.two.1Sampling programme: Typa of sample: fruits (Mango and Banana) and vegetables (Tomato, Chilli, Caulioflower, Cabbage). Sampling location: From 2 reputed wholesale markets like.. of West Bengal. Frequency and duration of sampling: After in each and every month for a single year. Volume of sample: 1 kg of every single sample. 4.2.2pesticide residues to be monitored: All the pesticides listed in table two. four.3Decontamination studies The pesticides are to be selected on the basis of their greater use pattern in W.B. the sa]elected pesticides are listed as follows: OC (?-endosulfan, ?-endosulfan endosulfan sulfate, dicofol OP: Chlorpyriphos, Quinalphos, Dimethoate, Triazophos, Malathion, Methyl parathion, phosphamidon, monocrotophos, metasystix; Synthetic pyrethroids: Cypermethrin, Deltamethrin and Fenvalerate. four.3.1Decontamination processes to become followed: 4.3.1.1Washing with water: Chopped samples will probably be taken inside a tray containing water as well as the material will probably be gently rubbed with water for about one minute and also the water will be decanted or it really is rinsed under running tap water for 130 sec., with gentle rotation by hand . washing is to be repeated twice or thrice. four.three.1.2Salt water washing: Chopped samples is going to be dipped in a beaker containing 2% or 55 sodium chloride answer. After 10-15 minutes the plant samplws will probably be gently rubbed by hand in salt solution and salt water will probably be decanted. Then the samples will likely be washed in water. 4.three.1.three Boiling/Cooking: Unwashed samples wil be chopped and boiled within a beaker till the water is fully evaporated covering the containr with or with out lid. Samples is usually to be allowed to cool. 4.three.1.4 Combination from the above strategies like soak in water for 15 min., rinse with water, reduce into pieces and boiled in water 4.three.1.5Wash with soap solution, rinse with water.
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