Identification Of Pesticide Residues Research Articles

Preliminary Studies on the Determination Bb Modern Methods (GS, GS/MS) of Organochlorine Pesticides in Cereals

Pesticides reach the grain directly as a result of phytosanitary treatments applied and indirectly through acquisition of water and soil. Time to disappearance of half the quantity of soil is: 1-4 years aldin, 1-7 years dieldrin, 2-10 years DDT. In areas where, the use of organochlorine pesticides was abandoned long ago than in our country, the contamination of these products is steadily decreasing but continuous monitoring. Separation and identification of compounds present in a sample using GC / MS is more powerful than if the same sample would be analyzed only by GC content or by MS. If the sample is analyzed by gas chromatography may arise some confusion, because there is a possibility that two molecules have the same retention time. Similarly, if the MS analysis is performed it is possible that two molecules have similar mass spectra. When, however, combines gas chromatography with mass spectrometry is highly unlikely that two different molecules behave similarly in the gas chromatograph and mass spectrometer. In this way the identification of pesticide residues in various matrices is not only based on retention times but also on mass spectra, thus eliminating the possible confusion that could arise if the identification were done using only one of the methods mentioned (compounds that have the same retention time or molecules with similar mass spectra).

High throughput analysis of 150 pesticides in fruits and vegetables using QuEChERS and low-pressure gas chromatography–time-of-flight mass spectrometry

A higher monitoring rate is highly desirable in the labs, but this goal is typically limited by sample throughput. In this study, we sought to assess the real-world applicability of fast, low-pressure GC–time-of-flight MS (LP-GC/TOFMS) for the identification and quantification of 150 pesticides in tomato, strawberry, potato, orange, and lettuce samples. Buffered and unbuffered versions of QuEChERS (which stands for “quick, easy, cheap, effective, rugged, and safe”) using dispersive solid-phase extraction (d-SPE) and disposable pipette extraction (DPX) for clean-up were compared for sample preparation. For clean-up of all sample types, a combination of 150 mg MgSO 4, 50 mg primary secondary amine (PSA), 50 mg C 18, and 7.5 mg graphitized carbon black (GCB) per mL extract was used. No significant differences were observed in the results between the different sample preparation versions. QuEChERS took <10 min per individual sample, or <1 h for two chemists to prepare 32 pre-homogenized samples, and using LP-GC/TOFMS, <10 min run time and <15 min cycle time allowed >32 injections in 8 h. Overall, >126 analytes gave recoveries (3 spiking levels) in the range of 70–120% with <20% RSD. The results indicate that LP-GC/TOFMS for GC-amenable analytes matches UHPLC–MS/MS in terms of sample throughput and turnaround time for their routine, concurrent use in the analysis of a wide range of analytes in QuEChERS extracts to achieve reliable quantification and identification of pesticide residues in foods.

Development of a multi-residue method for the determination of pesticides in cereals and dry animal feed using gas chromatography–tandem quadrupole mass spectrometry: II. Improvement and extension to new analytes

This paper describes the extension and re-validation of a previously published multi-residue method to currently 140 pesticides and 4 pesticide degradation products in cereals and feedingstuffs. The pesticides were extracted using buffered QuEChERS (“quick, easy, cheap, rugged, effective and safe”) method and then cleaned up using dispersive solid-phase extraction with Bondesil PSA and C18 sorbents, and optionally by a freezing-out clean-up step. The final extracts were analyzed in a single injection gas chromatographic-tandem quadrupole mass spectrometric (GC–MS/MS) acquisition method. A high degree of confidence was achieved by entering two multiple reaction monitoring transitions per compound. In this way, quantification of analytical results and unequivocal identification of pesticide residues in compliance with the recent European Union criteria could be done in a single analysis. Thorough optimization of the GC–MS/MS acquisition conditions and application of an effective clean-up procedure has resulted in a remarkable enhancement of the validation parameters. The linearity of the calibration curves was excellent in matrix-matched standards, and yielded the coefficients of determination ( R 2) ≥ 0.99 for approximately 96% of the target analytes. Average recoveries of the pesticides spiked at 0.01 mg kg −1 into a feed mixture and wheat grain were in the range 70–120% with associated RSD values ≤20% for approximately 60% and 67% of the compounds, respectively. At the higher spiking levels of 0.05, 0.1 and 0.5 mg kg −1 average recoveries and RSDs readily met the validation criteria for nearly all the studied pesticides. Based on these results, the proposed approach has been proven to be highly efficient and suitable for routine determinations of multi-class pesticides in a range of cereal and related matrices. Up to now, 145 samples of matrices of differing complexity including cereals grain, bran, whole ears, straw, hay, feed mixtures and other samples such as malt, starch and dry vegetables have been analyzed. A total of 15 different pesticides have been detected, among which pirimiphos methyl (19 cases), deltamethrin (14 cases), tolylfluanid (5 cases), dichlofluanid (5 cases), and tebuconazole (4 cases) were the most frequently encountered ones.

Use of gas-liquid chromatography with electron-capture and thermionic-sensitive detection for the quantitation and identification of pesticide residues

A gas chromatographic methodology that exploits combination of different columns and different detectors for testing residues of over 150 pesticides is proposed. Two gas-liquid chromatographs were set up each with two capillary columns of different polarities, DB-5 and DB-1701. Each column was connected to a precolumn with deactivated silica which was in turn connected to the injector. Each column was coupled to an electron-capture detector in one instrument and a thermionic-sensitive detector in the other. Standard solutions containing each pesticide, with ethion used as a reference peak to calculate the relative retention time (RRT), were injected into each gas chromatograph. RRT values for each column-detector combination are reported. Two columns of different polarities allowed identification and separation of most of the pesticides studied. Qualitative confirmations achieved by comparing the RRT values obtained by columns of different polarities on the same detectors as well as on different detectors are discussed. The instrumental configuration and the analytical conditions used may be a useful tool for the determination and confirmation of the great number of pesticides residues that may be extracted by multiresidue methods.

Pesticide residue analysis in foodstuffs applying capillary gas chromatography with atomic emission detection State-of-the-art use of modified multimethod S19 of the Deutsche Forschungsgemeinschaft and automated large-volume injection with programmed-temperature vaporization and solvent venting

Atomic emission detection (AED) provides high element-specific detection of all compounds amenable to gas chromatography (GC). The heteroatoms nitrogen, chlorine, phosphorus, sulfur, bromine and fluorine, which are important elements in pesticide residue analysis, are of major interest. A main drawback of AED is its lower sensitivity with respect to other selective detection methods used in pesticide residue analysis such as electron-capture and nitrogen-phosphorus detection. This holds true especially for the important nitrogen trace. For this reason, more sensitive detection can be achieved by injection of larger volumes or higher concentrations of sample extracts, because matrix compounds were usually registered only in the carbon, hydrogen and oxygen traces. This paper focuses on recent developments from the authors' laboratory in order to demonstrate the feasibility of screening analyses with the identification of pesticide residues down to the 0.01 ppm concentration level in plant foodstuffs. This has been achieved by means of automated large volume injection with programmed-temperature vaporization and solvent venting as well as careful optimization of make-up and reactant gases with AED. Clean up follows the principle of multimethod S19 of the Deutsche Forschungsgemeinschaft in a reduced procedure. After elimination of lipids and waxes by gel permeation chromatography, extracts from 10 g of the food samples were concentrated to 200 μl, of which 12.5 μl were introduced into the GC-AED system. Two analyses were usually performed with the element traces of sulfur, phosphorus, nitrogen and carbon in the first run and chlorine and bromine in the second run. Fluorine and oxygen were not detected in any screening analyses. The method has proved to be of great value especially with “problem foodstuffs”. The limits of detection were determined for 385 pesticides and are presented together with their retention data.

Identification of pesticide residues in real matrices by combining retention indices and specific multidetection responses

AbstractA previous paper reported the possibility of using the ratio between the responses of two different specific detectors to a single compound (detector response ratio, DRR) as an identification criterion for that compound, in combination with its retention index.This article gives some applications of DRR in the identification of some pesticides in four different fruits (apples, apricots, strawberries, and peaches) in a range varying from 0.02 to 1.3 ppm, by means of their ECD/FPD DRRs. After clean‐up GC analyses were performed on a single column with dual parallel detection; a personal computer system was used for data analysis.

Applications of gas chromatography—mass spectrometry in monitoring environmentally important compounds

The use of gas chromatography-mass spectrometry (GC-MS) with electron impact (EI) and positive and negative chemical ionization (PCI and NCI, respectively) is a valuable confirmatory technique for unequivocal identification of pesticide residues and polychlorinated biphenyls in different environmental matrices. This article outlines some of the most important developments and makes recommendations for selecting the mode of GC-MS operation. Emphasis is placed on less commonly used techniques such as NCI, which provides high selectivity and sensitivity for specific groups of pollutants. The coverage is restricted and represents the personal perspective of the author.

Routinemethode zur dünnschichtchromatographischen identifizierung der pestizidrückstände aus des klassen der triazine, carbamate, harnstoffe und uracile

Routine method for identification of pesticide residues of triazine, carbamate, urea, and uracil type compounds by thin-layer chromatography For a reliable and reproducible identification by thin-layer chromatography ten systems for the separation and detection of sixty-one pesticides—mostly herbicidal—have been developed, based on a general technique described previously. Two or three systems for each group of pesticides enable the analyst to differentiate almost all of the sixty-one compounds unambiguously, only three pairs of substances remaining unresolved. These results can be obtained by statistical evaluation of the variabilities in the R F values of these systems.

THIN-LAYER CHROMATOGRAPHY IN THE DETERMINATION OF PESTICIDE RESIDUES.

Chromatography, in its many forms, has provided the residue chemist with one of the most significant techniques for the separation and subsequent identification of pesticide residues. The growing need for general but systematic analytical procedures for the detection of several pesticides has been largely fulfilled by the introduction of chromatographic techniques.

Identification of Pesticide Residues in Extracts of Fruit, Vegetables and Animal Fats. III. Metabolites of Chlorinated Hydrocarbon Pesticides in Animal Depot Fat

Identification of Pesticide Residues in Extracts of Fruit, Vegetables and Animal Fats. III. Metabolites of Chlorinated Hydrocarbon Pesticides in Animal Depot Fat

Identification of Pesticide Residues in Extracts of Fruit, Vegetables, and Animal Fats II. Rapid Qualitative Chemical Tests for Captan and Methoxychlor

Journal Article Identification of Pesticide Residues in Extracts of Fruit, Vegetables, and Animal Fats II. Rapid Qualitative Chemical Tests for Captan and Methoxychlor Get access W P Mckinley, W P Mckinley Food and Drug Laboratories, Canada Department of National Health and Welfare, Ottawa, Canada Search for other works by this author on: Oxford Academic Google Scholar Sheila I Graham Sheila I Graham Food and Drug Laboratories, Canada Department of National Health and Welfare, Ottawa, Canada Search for other works by this author on: Oxford Academic Google Scholar Journal of Association of Official Agricultural Chemists, Volume 43, Issue 1, 1 February 1960, Pages 89–91, https://doi.org/10.1093/jaoac/43.1.89 Published: 04 February 2020

Identification of Pesticide Residues in Extracts of Fruits, Vegetables, and Animal Fats. I. Chromatography

Identification of Pesticide Residues in Extracts of Fruits, Vegetables, and Animal Fats. I. Chromatography