Gas Chromatography-Mass Spectrometer Electron Ionization (GC-MS -EI)method for the Analysis of MalathionResidue in Tomato

In this a study tomato sampleswere collected from Khartoum, extracted with acetone, dichloromethane and petroleum ether (1:1:1) and cleaned up by florisil column. Malathion quantitative determination is carried out by gas chromatograph-mass spectrometerusing the optimum ionization mode electron ionization (EI). The detection ofmalathionis confirmed by retention time and comparison of primary and secondary ions.Recovery studies were performed at two spikes (0.5,0.25mg kg-1) fortification levels of malathion and the recovery obtained ranged from 81% to 97%. The method showed good linearity(R²> 0.995) over the range assayed (from 0.05 to 7.0mg L-1) and the calculated limits of detection (LOD) and quantification(LOQ) were0.03 mg kg-1and 0.11 mg kg-1, respectively. These limits werelower than the maximum residue levels(MRL) established by European legislations (0.5mg kg-1).

Determination of Organochlorine Pesticide and Pyrethroids Residues in Tea with Gas Chromatography

A method for the simultaneous determination of organochlorine pesticide and pyrethroids in tea was established by gas chromatography equipped with electronic capture detector (GC-ECD).The organochlorine and pyrethroids in tea were extracted by acetonitrile, then filtered and concentrated organic phase, and separated and purified through a florisil column, then concentrated again and diluted with hexane to scale. The organochlorine pesticide and pyrethroids were analyzed by GC-ECD and qualified with external standard method. Experiments show that seven kinds of agricultural chemicals’ peak time range from 16.362 to 32.010 min, correlation coefficient in the range of 0.9992-0.9999, with excellent linearity. The lowest examination limits range from 0.018 mg/kg to 0.099 mg/kg and the recoveries between74.5% and 116% with relative standard deviations(RSD) of 1.4%-8.7%. The results showed that proposed method could used to determine these two kinds of pesticides in tea.

Content Evaluation on Organochlorine Pesticides in Local Vegetables

According to Codex Alimentarius, pesticides are considered as chemicals that prevent, suppress, destroy and repel some pests during manufacture, storage, transport or processing of food, feed and agricultural goods. These chemicals can also be used as plant growth regulator, as defoliant, agent inhibition. The purpose of this study was to evaluate the content of organochlorine pesticides in home-grown vegetables products. The objectives were the establishment of the working matrices and the organochlorine pesticides determination in the matrices chosen by GS method. Due to the high cost of analysis, the vegetable matrix was consisted in 12 sample- lettuce and spinach samples grown in garden and roots samples (carrots, parsley, parsnip and celery) from both home-grown production. Organochlorine pesticide residues were extracted from the sample with acetonitrile and petroleum ether, purified by passage through florisil column and eluted with a mixture of ethyl ether and petroleum ether. Concentrated eluate was subjected to gas chromatographic determination.In all examined samples, there were identified organochlorine pesticide residues with high residual, HCH, DDE, DDT, DDD, endosulfan, and heptachlor, some being above the maximum allowed by European legislation

Researches Regarding the Level of Organophosphoric Pesticides Residues in Raw Milk Used for Scalded Paste Cheese Production

The aim of the research was to establish the level of organochlorine pesticides residues (αHCH, β-HCH, γ-HCH (Lindan), DDT-T, Heptaclor, Dieldrin, Endrin) in the raw milk used for cheese production. Sixty samples of milk were analyzed, using the gas-chromatographic method from AOAC (Association of Official Analytical Chemists). Thus, the pesticides residues from milk fat or from the ether extract of the sample were selectively extracted with acetonitril and petroleum ether and purified on florisil column and than eluted with petroleum ether, diethyl ether and ethanol mixture.Â

Comparison of methods for bifenthrin residues determination in fermented wheat samples

Efficiency of three different sample preparation methods for GC/MS determination of bifenthrin residues in wheat (Triticum spelta) samples fermented by Lactobacillus plantarum was tested. The first method was based on a methanol:acetone=1:1 extraction folowed by a purification on columns containing mixture of aluminium oxide and activated charcoal slurry-packed and eluted with dichlormethane, the second was based on methanol:acetone=1:1 extraction folowed by the purification on florisil column and elution by ethil acetate:acetone=4:1, while the third tested method was based on a combination of the first two mentioned methods, thus methanol:acetone=1:1 extraction and clean-up throught columns filled with a mixture of aluminum oxide and activated charcoal slurrypacked and eluted with ethil acetate:acetone=4:1. The second method was the most effective for obtaining satisfactory recoveries for bifenthrin in a range of 79-83% for four fortification levels, with good reproducibility i.e. RSD% in a range of 2.2-7.4%. The chosen method was further optimized by assessing the optimum volume of elution solvent used during the clean-up procedures. The highest recovery of 82.1% was obtained after elution with 25 ml of solvent. Overall, two-step extraction with 25 ml of methanol:acetone=1:1 solvent mix for 30 min, followed by clean-up procedure through a glass column with florisil coupled with elution with 25 ml of ethyl acetate: acetone=4:1, allows simple, efficient and reliable GC/MS detection of bifenthrin residues from wheat grain fermented by L. plantarum.

Multiresidue analysis of pesticides in soil by liquid-solid extraction procedure

A multiresidue method for simultaneous determination of four pesticides (diazinon, acetochlor, aldrine and carbofuran) belonging to different pesticide groups, extracted from soil samples, is described. The method presented is based on liquid-solid extraction (LSE) and determination of pesticides, i.e. the pesticides were extracted by methanol- acetone mixture, purified on florisil column and eluted by ethyl acetate-acetone mixture. Optimization of the main parameters affecting the LSE procedure, such as the choice of purification sorbent, as well as the elution solvent and its volume, were investigated in details and optimized. Also, validation of the proposed method was done. Gas chromatography-mass spectrometry (GC-MS) was used for detection and quantification of the pesticides studied. Relative standard deviation (RSD) and recovery values for multiple analysis of soil samples fortified with 30 ?g/kg of each pesticide were below 8% and higher than 89%, respectively. Limits of detection (LOD) for all the compounds studied were less than 4 ?g/kg.

Development of a Gas Chromatographic/Mass Spectrometric Method for Determination of Phthalates in Oily Foods

A GC/MS method was developed for simultaneous determination of 12 phthalates and four other plasticizersacetyl tributyl citrate, di(2-ethylhexyl) adipate, dibutyl sebacate, di-isononyl cyclohexane 1,2-dicarboxylate (DINCH)in vegetable oil, pesto, and tomato sauce. Samples were extracted with acetonitrile and cleaned on a Florisil column. The final extract was analyzed by GC in combination with ion trap MS. The phthalates and di-isononyl cyclohexane 1,2-dicarboxylate were detected by MS/MS, while the other three plasticizers were monitored in the same GC run using full scan mode. The analytical process was validated in each matrix by the analysis of blank samples. Performance characteristics, such as linearity, LOQ, precision, and recoveries were studied. Studies at fortification levels of 0.25200 mg/kg gave mean recoveries ranging from 71 to 106 and RSD values between 7 and 12 for all compounds. LOQs were 0.0500.10 mg/kg for all the target compounds except di-isononyl phthalate, di-isodecyl phthalate, and DINCH (2.0 mg/kg).

Measurement of T-2 and HT-2 Toxins in Eggs by High-Performance Liquid Chromatography with Fluorescence Detection†

T-2 toxin is a mycotoxin produced by several species of common fungi capable of infesting human food and animal feeds. Lower-quality feeds given to chickens may be contaminated with T-2 toxin, which may affect their health. The literature suggests that T-2 toxin is transmitted from the hen to the eggs. This article describes the development of a liquid chromatographic assay for T-2 and the related mycotoxin HT-2 in eggs. T-2 and HT-2 toxins were isolated from spiked eggs with a tandem charcoal-alumina-Florisil column and immunoaffinity column cleanup. The isolated toxins were derivatized with the fluorophore 1-anthroyl nitrile, separated by high-performance liquid chromatography, and quantitated by fluorescence. The limit of detection of the method was 1 ng ml−1 (parts per billion) of T-2 and HT-2 in whole (with shell removed) eggs. The limit of quantitation for both toxins was 5 ng ml−1. Recoveries from spiked eggs over the range from 5 to 50 ng ml−1 averaged 89.2% for T-2 and 100.3% for HT-2, with coefficients of variation of 3.5 and 8.2%, respectively. This method is sensitive enough to be used to check for the presence of T-2 or HT-2 toxins in eggs.