Decontamination of pesticide residues in fruits and vegetables

Preferably, the samples used in processing studies should contain field CCR quantifiable treated waste as close as possible to the MRLs, so that measurable residues are obtained, and the transfer of the factors for the various processed products can determined. A transfer factor gives the relationship between the concentration of residues in processed raw material for the RAC. For example, if the concentration of waste is 0.5 mg / kg of olives and 0.2 mg / kg in olive oil, transfer factor is 0.2/0.5 = 0.4. A factor 1 (= concentration factor) indicates a concentration effect processing procedures. Increased waste, either by increasing application rates, reducing pre-harvest interval (PHI) or spiking the RAC with the principle asset and its metabolites in vitro is not, as a rule, desirable. Spiking is only acceptable if waste can be shown that RAC shall consist only of residues from the surface. However, in some cases, especially when the waste in the CCR are near the analytical limit of determination, treatment on the ground in exaggerated rates or shortened PHIS is advisable to obtain sufficient residue levels of processing studies.

The first step in the home or commercial food processing is food preparation using different mechanical processes such as removal of damaged or soiled or parts of crops, washing, peeling, peeling or hulling. This often leads to significant reductions in the amount of pesticide residues remaining in edible parts (Petersen, et al., 1996; Celik et al., 1995; Schattenberg et al., 1996).

WASH

The household washing procedures are usually performed in the operating or standing water at moderate temperatures. Detergents, chlorine or ozone can be added to the wash water to improve the efficiency of washing procedure (Ong et al., 1996). If necessary, several wash steps can be performed accordingly.

The effects depend on physico-chemical pesticides, such as water solubility, hydrolysis rate constant, the volatility of and octanol-water partition coefficient (POW) in connection with the actual physical location of waste washing processes lead to the reduction of hydrophilic residues found in the area of crops. In addition, the wash water temperature and type of cleaning has an influence on the residue level. As noted by Holland et al. (1994), hot washing and the addition of detergents are more effective than washing with cold water. Wash with the gentle touch of the hand under the tap water for 1 min dislodged pesticide residues significantly (Barooah and Yein, 1996). Systemic pesticide residues and lipophilic not removed significantly by washing.

Table (1) shows examples of the effects of washing the residue levels of different pesticides applied to fruits and vegetables.

PEELING

The outer leaves of vegetables often contain residues of pesticides applied during the growing season. Therefore, peeling or cutting procedures reduce the residue levels in leafy vegetables. Peeling root, tuber and bulb vegetables with a knife is a common practice in the house. Many examples show that most of the residue concentration is at or on the skin. Peeling of the CCR can remove more than 50% of pesticide residues in products core. Therefore, the removal of the shell is nearly complete elimination of waste, so that leaves little in the edible parts. This is especially important for fruits that are not eaten with the peel, like bananas or citrus fruits. Reynolds (1996) showed that peeling or cutting the carrot reduces waste chlorfenvinphos, primiphos-methyl, quinalphos, triazophos result in a transfer factor of 0.2. However, the commercial shell peeling process can be used for food animal or for the production of essential oils (citrus) or pectin (citrus, apple, etc). For such industrial processes is important to realize that, especially not systemic surface residues are often concentrated in the shell. For systemic pesticides, peeling, it can be as effective as demonstrated Sheikhorgan et al (1994). After application of cucumbers thiometon no reduction in the levels of residues could be detected in peeled cucumbers.

Under Codex Alimentarius, as in other international standards, MRLs refer to the whole fruits, which is suitable for assessing compliance with GAP. These MRLs are minor, however, in assessing dietary exposure to pesticides from fresh fruits that are peeled (Holland et al., 1994).

COOKING

Cooking procedures at different temperatures, the duration of the process, the amount of water or food additives, and system type (open or closed) may have an impact on the level of waste. Typically, waste is reduced during the cooking process by volatilization in open systems or closed systems by hydrolysis. In any case, the addition of diluted liquid kitchen waste. Several studies reported on the dissipation of pesticides on crops during cooking. In addition to the studies summarized in Table 1, the behavior of organophosphorus pesticides chlorfenvinphos, fenitrpothion, Isoxathion, methidathion and during prothiophos Cook was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased during the cooking process for the time boiling. According to its solubility in water, pesticide translocates some raw materials in the cooking water. Moreover, the pesticide remained in food processed according to their octanol-water partition coefficient, which is an indicator of hydrophilic or lipophilic properties of the compound. In exceptional cases, the cooking processes can cause degradation of pesticides, obtaining a reaction product of toxicological significance. For example, daminozide UDMH is degraded (1, 1-dimethylhydrazine), which is much more potent than the parent compound (Leparulo-Lofus et al., 1992). Another example is the formation of ETU (ethylenethiourea) of EBDCs (ethylene bis dithiocarbamate) fungicides as mancozeb, during the heating processes (Petersen et al., 1996).

Immersion in a chemical solution

Sodium chloride solution is widely used to decontaminate pesticide residues of various fruits and vegetables. there are several studies to demonstrate the effectiveness of salt water wash to remove pesticides of crops. In this process, the sample of chopped fruit and vegetables are placed in a beaker with 5% sodium chloride solution. After 15 minutes samples plants rubs his hand gently on salt and water solution is decanted alt. Examples of the effect of treatment with saline in the levels of various pesticide residues applied to the plants have been shown in Table 1.

Kumar et al (2000) reported that the immersion of green chiles 2% solution of salt during 10 minutes followed by washing with water proves effective, facilitating the elimination of waste from 32.56 and 84.21% corresponding to 0 and 5 days after spraying of triazophos (700 g ai / ha), while acephate residues were taken to an area of 78.95% on day zero. Following the same technique of Kumar et al (2000) And66.93 observed reduction 90.56% for 0 and 5 days after spraying of cypermethrin in the chiles.

Dip fruit processing in NaCl, HCl, acetic acid, NaOH solution of potassium permanganate eliminates 50-60% of the surface residues of synthetic pyrethroids compared with 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b).

NaOH water solution, potassium dichromate, acid acetic acid and soap solution used as decontamination agents for tom … … … ….

Treatment of fruit with a 2% dip in solution tamarind for 5 minutes followed by washing with tap water and steam cooking for 10 min. Was found to remove the residue of monocrotophos, carbaryl and fenvalerate in a As of 41.81, 100 and 100% respectively. Treatment with 2% solution of salt was equally effective.

Dip eggplant treatments wioth fruit water, sodium chloride solution of HCl, acetic acid solution of potassium permanganate solution were found to remove 30-33% fenvalerate residues of permethrin, cypermethrin and deltamethrin; NaOH solution Teepol 40-45% (detergent) solution of 50-60%. The effect of washing on the reduction of waste decreased progressively in the second and third harvests.

Many experiments were conducted with the three common household prepared to know. washing with water, salt water wash and cook to evaluate their relative effectiveness in reducing pesticide residues in different plants. The results are summarized in the table below.

Table: Effect of washing, washing and cooking salt in the levels of pesticide residues.

Crop% of pesticide residues reference evicted * Results

Washing with

Salt water wash water Kitchen

Cauliflower Methamidophos 41-48 46-47 46.94

-53.54 Further reduction was caused by cooking. Jacob and Verma (1990)

Okra

Methamidophos

64-72

19-58

58-64 water washing can remove the maximum residues that indicates its maximum solubility in water, although all processes below TMRL values. Jacob and Verma (1990)

Cauliflower alpha-cypermethrin

_ 7-38

12-17 was more effective cleaning the kitchen, probably due to the thermal stability of cypermethrin. Malik et al (1997)

Cabbage

Chlorpyrifos

Quinalphos

38

41

52.13

56.50

54.3

55 residues of three processes have somewhat reduced. They can reduce the residues below the MRLs. Thus, a waiting period of a minimum of one and two weeks respectively, it was suggested, regardless of washing and cooking quinalphos chlorpyrifos on cabbage. Nagesh and Verma (1997)

Cow pea

Metasystox

Carbalyl

84.3

87.5

86.4

88.7

83.4

Only 80.8 boiling sheath samples could decontaminate residues from the surface or inside the tissue to the extent of the safety limits by day 10 of treatment. Dikshit et al (1984)

Cauliflower

Malathion

60

70

80 Kitchen was more effective and reduced the value TMRL a week to zero days. Jacob and Verma (1989)

Bhindi

Quinalphos

61.84-64.35

43-53

78-82

Both washing with water and salt water wash down waste MRLs below zero days in the kitchen so did the maximum reduction of the resulting waste.

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 higher due to the kitchen compared to the laundering of all insecticides.

Bhatia and

Verma (1994)

The leaves and studded with heads of cabbage and cauliflower pods Indian rape seed

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)

Kitchen maximum residue dislodged.

The wash water removes the maximum DDT residue while cooking is effective in removing carbaryl and malathion residues.

Dikshit et al (1986)

Elkins et al (1968)

The above table can say that the kitchen is more effective in reducing the different plant residues of various vegetables, though in some cases washing with water was effective to reduce initial pesticide residues and found that with aging of the waste or with increasing sampling days during the treatments the washing effect is reduced to eliminate the toxic substance to the same extent that the from samples collected immediately after spraying boiling or cooking is found to be effective. One of the possible reasons for high percentage of elimination of toxic substances from the samples taken immediately as most of the residues on the surface of the samples and therefore is very easily removed by simple 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 of the waste is migrating within of the deeper tissues or firmly adhere to the rough surface of some vegetables. On the other hand, washing can reduce the waste to the level of security compared with boiling.

There are some studies in the three culinary processes proved effective in reducing residues below the MRL value. According Jacob and Verma (1991) residues of treated quinalphos in cauliflower crop was reduced only to some extent by various processing house, like washing and cooking. Nagesh and Verma (1997) felt that the ineffectiveness of the house for decontamination processes treated cabbage may be due to the strong adsorption properties quinalphos and chlorpyrifos.

Effect of household preparation for Multiresidue decontamination of pesticides in fruits and vegetables

Low levels of pesticide residues were detected in 97 (40%) of samples tested after 243 meters go for normal washing, peeling and cooking procedures. The number of samples containing detectable residues was reduced to 47 (19%) after household preparation. These results indicate that the residue level in most commodities fell substantially after the preparation of the home (Schattenberg et al., 1996)

Ramesh and Balasubramanian (1999) conducted a study with fruits and vegetables collected from local markets of Chennai and fortified with known concentrations of various pesticides followed by a study of decontamination of the preparations different households such as washing, cooking, peel 65-95% resulting from decontamination of pesticide residues in different stages of 512 samples analyzed market premium, organochlorine and organophosphorus pesticides present in the 12 samples were removed result in residues well below the limits of acceptable toxicity.

A rinse with tap water reduces short pesticide residues in many types of products (Krol et al., 2000). Rinse the waste eliminated nine of the twelve pesticides studied. Between captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyrifos, bifenthrin and DDE, vinclozolin residues, bifenthrin and chlorpyrifos were not removed. This study confirms that the water solubility of pesticides does not play an important role in the observed decline. Most waste pesticides appear to reside on the surface of the products that are eliminated by the mechanical action of washing.

Early studies of the effects of preparation commercial and household pesticides residues in fruits and vegetables were summarized by Zabik (1987). Early studies showed a reduction of waste to be substantial with a percentage reduction of chlorinated hydrocarbons from 50 to 99% + range for the commercial preparation and from 14 to 99 +% for home preparation with the exception of parathion in spinach and broccoli, and prewparation home commercvial organophosphate residues substantially reduced the overall decrease, be in the high 80 or from 90%. Waste carbamate was reduced by 58 to 99 +% when plants were commercially processed but only by 11 to 92% on home preparation.

A recent study Korea supports these previous studies (Lee and Lee, 1997). They found that 45% of the organophosphate residues are removed when food is washed in water, 56% with detergent, 91% with peeling, and 51% with blanching.

Methods multiresidue analysis of pesticides in fruits and vegetables

Analysis by gas chromatography

Nakamura et al (1994) developed a method for multiresidue analysis of 48 pesticides (20 organophosphates, organochlorines, 7, 14 organonitrogen pyrethroid pesticides and 7) allows for Japan on the basis of capillary GC after extraction of pesticides nacetone samples of vegetables and fruit or acetonitrile containing lipid crops reextraction followed by ethyl acetate (test solution). Organophosphorus pesticides were directly determined by GC-FPD. Organonitrogen Pesticides were determined by GC-FTD (GC-NPD), after cleaning by silica gel chromatography. Organochlorine pesticides and pyrethroids, were measured by GC-ECD after clean up by Florisil column chromatography. The recovery of ten crops in fortification levels of 0.05-0.25 ppm is 42,5-128,5%. the limits of detection were 0.001 ppm for organophosphates and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.

A multiresidue method was used by Dejonckheere et al (1996) for the determination of organochlorine pesticides and organonitrogen organophosphorus pesticides in vegetables and fruits which were extracted with acetone followed by liquid-liquid separation with water: pesticides in the petroleum ether phase apolar, polar extracted from the aqueous layer with dichloromethane and analyzed by gas chromatography with electron capture (GC-ECD), flame photometric (GC-FPD) and thermionic specific (GC-TSD) detection.

The method used for multiresidue determination of 52 pesticides, including organophosphates, organochlorines, organonitrogen, pyrethroids and certain dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) using gas chromatography. The samples were extracted with acetone followed by the partition with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates were digested in a mixture of concentrated HCl, SnCl2 and water for the evolution of CS2, stated in an alcoholic solution of copper acetate and diethanolamine to form a yellow complex. The absorbance of yellow product was determined by spectrophotometry at 435 nm. The mean recovery and CV of the 52 pesticides were 72-118 and 1-20%, respectively, in addition levels of 0.01-1 ppm. The same type of method was also described by Kole et al (1998).

Krol et al (2000) used a multi-residue procedure for the determination of 12 pesticides in plants where the samples were extracted with 2 propanol and petroleum ether, followed by washing with distilled water 3 times. The final analysis of the samples was performed by GC-ECD, FPD, XSD and / or ELCD.

Ramesah and Balasubramanian (1999) describes a method for determining organochlorine and organophosphate pesticides organonitrogen in fruits and vegetables after extraction with 2-propanol and petroleum ether by mechanical shaker followed by distilled water partitioning and Florisil column cleanup for organized crime and organophosphate pesticides. For pesticides organonitrogen extraction was performed with acetone followed by partitioning with 10% NaCl and ethyl acetate and column cleanup on silica gel. organochlorine and organophosphorus compounds organonitrogen were analyzed by GC-ECD, GC-NPD and GC-FPD, respectively.

Using GC-ECD, the efficiency of acetonitrile and acetone to extract the 8 pyrethroids 6 fruit and vegetable samples were compared by Pang et al (1997). The extraction efficiency of acetone was competitive acetonitrile with fruit and vegetable samples at 6. Robustness tests further demonstrated that the proposed method is simple, accurate with good precision and suitable for multiresidue analysis of pyrethroids in various agricultural products.

Waste organophosphate and organochlorine pesticides from fruit and vegetables by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) in sulfur and phosphorus modes, and mass spectrometric detector (MSD) in selected ion monitoring (SIM) mode were determined by Thompson et al (1995) after extraction of the matrix solid phase dispersion (MSPD) as a result the recovery of 41-108% with relative SD of 2-14% in conc. range 0.5-10 mg / liter in oranges, lemons, grapefruits, pears, plums, lettuce and tomatoes.

A multiresidue method described by Sannino et al (1995) for the quantitative determination of 39 organophosphorus compounds (parent pesticide and its major metabolites) in 7 fatty foods processed from automated gel permeation chromatography with a column SX3 and Biobeads methylene chloride-cyclohexane (15 + 85) eluate after extraction with methylene chloride. Organophosphorus compounds are quantified by GC-FPD using OV-1701 and DB-5 columns. Average recovery of spiked samples at 0.025-1 mg / kg ranged from 50.6% to 185% for dichlorvos malaoxon. Determination limits were between 0.005 and 0.040 mug / ml. The results were confirmed by gas / mass spectrometry with ion chromatography of selected control.

Chromatography conditions for gas separation and identification of compounds were selected using two capillary columns of different polarities and two detectors, ECD and NPD for multiresidue quantitative determination of 37 pesticides in fruits and vegetables, and to study the efficacy of gel permeation chromatography after extraction cleaning ethyl acetate (Balinova, 1999).

Trova et al (1999) performed by liquid chromatography determination of pesticide residues (including azinphos-ethyl, azinphos-methyl, carbaryl, diflubenzuron, dinocap teflubenzuron) in vegetables after extraction by ethyl acetate / n-hexane and solvency of the system in place methylene chloride widely employed. Recoveries as required by the Guidelines for Residues Monitoring in the European Union where there was the solvency new system can be considered as an alternative to halogenated compounds, dangerous for their toxicity and harmful behavior to the environment in mining HPLC-active compounds determinable.

A wide range of detection method was proposed by Gelsomino et al (1997) for multiresidue analysis of 77 pesticides (12 organohalogen, 45 organonitrogens, 11 organophosphates and pyrethroids 9) in agricultural products by gas chromatography equipped with long, narrow canyon Fused silica open tubular columns and electron capture detector (ECD). The residues were extracted with acetone followed by dichloromethane and partition chromatography gel permeation cleanup. Recoveries of most pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.10 mg / kg 70-108%. The detection limits were below 0.01 mg / kg for early childhood.

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 efficient and reliable multiresidue method for determining nitrogen-52 and phosphorus-containing pesticide residues in a large number of vegetable samples in which samples were extracted with acetonitrile, and the separated acetonitrile layer was purified by gel permeation chromatography effluent is divided pesticide in 2 fractoions, pesticide fractions were respectively purified by a 2-step minicolumn cleanup, the split second through silica gel minicolumn; first fraction through the tandem minicolumn (florisil minicolumn inserted in mini silica gel column), which was eluted with acetone, petroleum ether (3 +7). The combined eluate was subjected to double-column gas chromatography with nitrogen-phosphorus and flame photometric detection. Recoveries of 52 pesticides in fortified samples ranged from 72 to 108% compared with the standard deviations of 2.17%, except for the recovery of methamidophos and chorothalonil. The detection limits of pesticides were satisfactory (0.001-0.009 mg / kg) for control of pesticide residues in vegetables.

Menkissoglu et al (2004) A study of the effects induced by the matrix for 16 common pesticides, more frequent monitoring surveys in pepper tomato and cucumber, with a method Simple multiresidue GC-ECD or NPD, without a previous cleanup step. Abnormally high GC responses and then the high rate of return of several pesticides in the extracts were obtained through a conventional calibration with pesticide in ethyl acetate solution.

A faster, less efficient, more environmentally safe extraction supercritical fluid (SFE) method was evaluated by Garcia et al (1996) more conventional extraction methods for extracting sonvent imidacloprid, methiocarb, chlorpyrifos, chlorothalonil, endosulfan-1, endosulfan-2 and endosulfan sulfate, pepper and tomato plants using mixtures of the sample: the sulphate magnesium chloride (5:7) to carryout the supercritical CO2 extraction and HPLC / DAD, GC / ECD and GC / FPD for analysis. The conditions were chosen SFE 300 atm, 500C, 200? L of methanol modifier static, 1 minute static time and dynamic extraction with 15 ml of CO2 and collection in 3 ml of ethyl acetate. Except for the imidacloprid, which was not recovered in any of the conditions tested, pesticide recoveries were higher than 80%.

A simplified method is described by Chaput (1987) in reversed phase liquid chromatography was used with post-column derivation and fluorescence detection to determine 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl and propoxur) and 3 related metabolites in fruits and vegetables after extraction of the sample with methanol followed of gel permeation chromatography (GPC) or GPC with on-line cleaning nuclear celite crops with high chlorophyll and / or content of carotene (for example, cabbage and broccoli). Recovery data were obtained by fortifying 5 different crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.5 ppm. Recoveries averaged 93% at both levels of fortification. The coefficient of variation of the method at both levels is
Makoto et al (1994) studied multiresidue procedure of 10 organophosphorus pesticides in establishing methods of analysis by gas chromatography capillary column with flame photometric (FPD) and spectrometric detector mass (GC-MS). Quantitative gas chromatography with a FPD was examined to determine the conditions for multi-column chromatography GC. Chromatography gas GC-MS has been studied to select the fragment ions suitable for the determination and identification.

Estimated GC-MS/LC-MS

Due to the mass spectrometer is capable of achieving higher levels of molecular specificity compared to traditional GC detectors and can be programmed to search ions of several hundred stations, GC / MS would be a promising method for exploring the regulatory agencies for monitoring pesticide residues in food daily supply (Cheng et al, 1994).

Cheng et al (1994) reported a multiresidue method using gas chromatography / mass spectrometry / selected ion monitoring (GC / MS / SIM) for the determination of captan, chlorothalonil, dichlorovos, dimethoate, EPN, phorate, primiphos-methyl prothiophos fruit and vegetable waste. Recoveries were between 46 and 108% at 0.5 mg / kg fortification level for each pesticide in apples, cabbages, cucumbers and grapes. The coefficients of variation were between 0.7 and 19%, with an average of 7.5%. The estimated detection limits of pesticides on crops were 0.1-0.05 mg / kg, except that capture detection limit was in the cultures of greater than 0.5 mg / kg.

A method based on solid phase extraction with a carbograph 1 cartridge and reverse phase liquid chromatography Mass spectrometry (LC / MS) with electrospray (ES) interface was described by Corcia et al (1996) for measuring traces of N-methylcarbamate insecticides in 10 different types of fruits and vegetables. Twelve carbamates added to the plant materials were extracted with methanol using a homogenizer followed by filtration, an aliquot of homogenate equivalent to 5 g of plant material was suitably diluted with water and passed through a 1 Carbograpg 1 cartridge extraction. Carbamates were eluted through 6 ml cartridge of a CH2Cl2/CH3OH (80:20 v / vegetables) of the mixture. The recovery of the analytes was better than 80%, regardless of the type array of vegetables in which analytes were added.

A fully automated method using solid phase extraction (SPE) sample cleanup and analysis online liquid chromatography with UV and fluorescence detection in tandem for the determination of carbendazim and thiabendazole in various crops was reported by Hiemstra et al (1995).

A total of 199 pesticides were determined by Fillion and al (1995) in fruits and vegetables by using acetonitrile as solvent and extraction of coal miniature-celite column cleanup followed by gas chromatography with mass selective detection in selective ion monitoring mode. Carbamates were analyzed liquid chromatography with post-column reaction and fluorescence detection. Recovery data were obtained through fortification of 3 matrices (pear, carrots and bananas) to 0.1-0.5 ppm.

Blasco et al (2004) uses a quantitative matrix solid phase dispersion and liquid chromatography-spectrometry of atmospheric pressure chemical ionization mass (LC-APCI-MS) method for the simultaneous analysis of dithiocarbamates and their degradation products in crops. The mean recovery ranged from 33 to 109%, and the relative standard deviation was between 4 and 21%, with limits of quantification ranged from 0.25 and 2.5 mg / kg.

A multiresidue analysis for the determination of 101 pesticides, including organophosphates, organochlorines, and pesticides containing nitrogen in crops by gas chromatography with mass selective detector was made by Chun et al (2003). Analysis was performed in selected ion mode monitoring. Samples were spiked with pesticides at 0.1-1.0 mg / kg. Recoveries of 90% of the pesticides morning between 70 and 110%, however, the recovery of acephate and folpet were very poor, ie
A high-performance analysis of multi-residue pesticide is a single extraction with ethyl acetate and a single column cartridge (consisting of two layers of water absorbent polymer (upper) and graphitized carbon (lower)) cleaning procedure in non-fatty vegetables and fruits was developed by Obana et al (2001). In a recovery test, 110 pesticides were off and the average recovery was over 95% of the spinach and orange. Most pesticides were recovered in the range of 70-115% with a relative standard deviation generally
A simultaneous and consecutive analysis methods of waste of pesticides in a large number of food samples by extraction with acetonitrile, followed by gel permeation chromatography (GPC) and the cleaning cartridge mini-column and then double-column GC equipped with ECD was investigated by Ueno et al (2004). Recoveries of 58 pesticides from fortified spinach, tomatoes, apples and strawberries were very good (70-121%), except acrinathrin, captan, captafol, dichlofluanid, and etridiazole (
The simultaneous determination of 251 residues pesticides and degradation products of fruit and vegetable samples by gas chromatography with mass selective detection in the selected control mode ion, and liquid chromatography with post-column reaction and fluorescence detection of N-methyl carbamates following acetonitrile extraction and octadecyl (C18) solid-phase cartridge cleaning and then cleaning in a second, through a carbon cartridge coupled to an amino propyl cartridge was described by Fillion and al (2004). Limits of detection range between 0.02 and 1.0 mg / kg for most compounds. Over 80% of the compounds have a limit detection _0.04 mg / kg.

Aguera et al (2002) used gas chromatography using a combination of positive chemical ionization (PCI) and electron impact (EI) ionisation modes and tandem mass spectrometry (GC-PCI/EI-MS-MS) as analysis method to determine 55 compounds organochlorines and organophosphates and pyrethroids used in crop protection. Pesticide residues were extracted from samples with a mixture of ethyl acetate and sodium sulfate obtain a final concentration before the sample of 1 mg / ml of extract. No additional cleaning was necessary measures. Good sensitivity and selectivity of the method were obtained with detection limits ranging from 0.07 to 4.21 mg / kg in all cases except for methamidophos, permethrin, cypermethrin and difenconazol [difenoconazole]. Recoveries on average between 52 and 114% were obtained and good linearity was observed in the ranges studied (r_0.994).

Multiresidue A simple, fast and sensitive for the determination of ten organophosphorus and organochlorine pesticides using a miniature extraction with ethyl acetate followed by large volume injection (10 μL) GC-EI-MS analysis in SIM (selective ion monitoring) mode was developed by Aguera et al (2004). The sensitivity and selectivity of the method were acceptable, with limits of detection (LOD) of less than 0.01 mg kg-1 with the exception of endosulfan-alpha and beta (0.05 mg / kg). The mean recovery of between 63-99% were obtained and good linearity was observed in the range of 0.01 to 1.00 mg kg-1.Repeatability and reproducibility studies gave relative standard deviations below 20% in all cases. The method was applied to the analysis of 110 vegetable samples, as part of the monitoring program of the Association of Producers and Exporters of Fruits and Vegetables Almeria.

A pesticide multiresidue method that enables quantitative, sequential analysis of a large number of samples of vegetables and fruits by chromatography gas-mass spectrometry was reported by Ueno et al (2004). The sample is extracted with acetonitrile and the extract was cleaned by a salting step followed by redissolution in ethyl acetate. Coextractives automatically removed by gel permeation chromatography with a graphitized carbon column, and then by a tandem column silica-gel/PSA cartridge. Recoveries of 82 of the 89 pesticides from fortified spinach, tomato, apple, strawberry and were within a Range 70 to 120%, and the relative values standard deviation of 80 of the 89 pesticides
Analysis of the methanol extract without other cleaning measures was conducted by liquid chromatography-ionization electrospray-tandem mass spectrometry mode that combines positive and negative ions for the determination of a group of 16 multiclass pesticides most commonly used in crop protection. The extraction step was performed with a mixture of ethyl acetate and sodium sulfate in the presence of 6.5 M NaOH. The average recovery obtained were between 70 and 110% in most cases with an accuracy of
A new analytical method using liquid chromatography with spectrometry tandem mass for the routine analysis of 31 multi-class pesticide residues and applied to approximately 50 samples of fruits and vegetables (green beans, cucumber, pepper, tomato, eggplant, watermelon, melon and zucchini) was developed by Garrido et al (2004). Extraction of the pesticides with ethyl acetate was out. The average recovery obtained for each pesticide cucumber ranged between 74 and 105% in two different fortification levels (n = 10 each) that ranged between 9 and 250 ng g -1 (depending on product). The uncertainty associated with the method of analysis was less than 23% for all compounds tested. The calculated limits of detection and quantification were generally

Proposed work plan

Multiresidue standardization of methods Pesticide analysis

Standard analysis of selected pesticides belonging namely, the different classes. OC (HCH (?,?,? Y? Isomer), DDT (OP-DDT, pp-DDT, op-DDD, pp-DDE), endosulfan ( "," Y endosulfan sulfate) and dicofol), OP (Dimethoate, Malathion, Methyl Parathion, Chlorpyrifos, Quinalphos, Triazophos, phosphamidon Metasystox dichlorvos and monocrotophos) and synthetic pyrethroids (cypermethrin, deltamethrin, fenvalerate) for monitoring and decontamination studies have been collected from various sources as follows:

No. Name of the pesticide Sl% Source Purity

Organochlorines

1?-HCH 99.5 EPA

2?-HCH 99.5 EPA

3?-HCH 99.5 EPA

4?-HCH 99.5 EPA

5 OP-DDT 99.7 EPA

6 PP-DDT 99.7 EPA

7 OP-DDD 99.7 EPA

8 PP-DDE 99.7 EPA

9?-Endosulfan 99.0 Excel

10?-Endosulfan 99.0 Excel

11 endosulfan sulfate Excel 99.0

Bayer 12 Dicofol 96.0

Organophosphates

Dimethoate 13 UPL 96.5

Malathion 14 UPL 97.3

15 methyl Bayer parathion 98.5

99.7 Chlorpyrifos 16 crop protection Denocil Ltd.

Sandoz Ltd. 17 Quinalphos 95.6

18 Phosphamidon 93.9 Bayer

40.8 Triazophos 19 Aventis Crop Science

Monocrotophos 20 UPL 77.0

Dichlorvos 21 —

22 Metasystox —

Synthetit pyrethroids CCSRI

Cypermethrin, 99.0 CCSRI

Deltamethrin

Fenvalerate 99.0

99.0 CCSRI

4.1.1 Stock solution pattern: stock standard solution of different pesticides are to be prepared in distilled hexane / acetone and diluted appropriately to serve as a working standard and mindividual check chromatography peaks of their suitability for multi-residue analysis.

4.1.2 Preparation of mixed standard solytion: from the individual standard solutions mixed standard solution was prepared for mdevelopment method and studies of decontamination.

4.1.3 Extraction and cleaning

From a review of the literature three methods proposed by Kole et al (1998), Nakamura et al (1994) and Obana et al (2001) have been selected to carry out the extraction and cleanup procedure that both the liquid-liquid and solid phase extraction column with a match against the development cartridges in a fast, easy and cost-effective method for detecting a wide range of pesticides.

4.1.4 Estimation of multi-residue pesticide

A gas chromatograph coupled with an electron capture detector (ECD) and nitrogen phosphorus detector (NPD) will be used for estimating pesticide residues. Operating conditions, also be studied as indicated in the chosen three methods.

4.1.5 Standardization of Mathod:

The method Wil selected to be normalized by performing a recovery study with the standard mixed by nailing in fruits and vegetables.

4.2 Monitoring Pesticide residue:

4.2.1 sampling program:

Typa Sampled fruits (mango and banana) and vegetables (tomatoes, peppers, Caulioflower, cabbage).

Place of sampling: From 2 wholesale markets renowned as … … .. West Bengal.

Frequency and duration of sampling: Once per month for one year.

Sample volume: 1 kg of each sample.

4.2.2 Pesticide residue control: All pesticides listed in Table 2.

4.3 Decontamination studies

Pesticides should be selected on the basis of their largest employer in the World Bank use the sa] chosen pesticides are follows: OC (?-endosulfan?-endosulfan endosulfan sulfate, dicofol OP: Chlorpyrifos, Quinalphos, dimethoate, triazophos Malathion, methyl parathion, phosphamidon, monocrotophos, metasystix; synthetic pyrethroids: cypermethrin, deltamethrin and fenvalerate.

4.3.1 decontamination procedures to be followed:

4.3.1.1 The water washing: Chopped samples taken in a tray containing water and the material is rubbed gently with water for one minute and the water is decanted and rinsed with water running tap water for 130 sec., with smooth rotation by hand. washing is repeated twice or thrice.

4.3.1.2 Salt water wash, the samples of minced is immersed in a beaker containing 2% or 55 of sodium chloride solution. After 10-15 minutes of samplws plant gently rubs his hand in a solution of salt and water salt is decanted. Then the samples are washed in water.

4.3.1.3 Boiling / Cooking: Wil dirty samples be cut and boiled in a beaker until the water is completely covering the containr evaporated with or without lids. The samples were allowed to cool.

4.3.1.4 Combination of the above methods, including soaking in water for 15 min., Rinse with water, cut into pieces and boiled in water

4.3.1.5 Wash with soap solution, rinse with water.

About the Author

Md. Wasim Aktar is a Senior Research Fellow in Export Testing Laboratory, APEDA, Govt. of India, under Deptt of Agricultural Chemicals, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India

Flame Test 07

Gamo Blue Flame PBA .177 Cal, 5.4 Grains, Pointed, 100ct $13.19 Specially formulated blue polymer tip causes rapid expansion in the ultra light, 5.4 grain PBA pellet. Velocity is enhanced an additional 30% over standard lead ammo. .177 caliber 5.4 grains Pointed 100 pellets