Effect of bromine oxidation on high-performance thin-layer chromatography multi-enzyme inhibition assay detection of organophosphates and carbamate insecticides

Akkad, Rami; Schwack, Wolfgang

doi:10.1016/j.chroma.2011.02.029

Cited by 19 publications

(10 citation statements)

References 31 publications

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“…Developed in 2003 by Anastassiades, QuEChERS sample preparation has been readily accepted by many pesticide residue analysts over the years [13,14]. In the section of instrumental analysis, a literature survey (Table 1) shows several methods for the detection of carbamate pesticide residues have been developed at low concentration levels in various samples, such as electrochemical detection [15], liquid chromatography [16,17,18,19,20,21,22,23,24], high-performance thin-layer chromatography [25], liquid chromatography with post-column fluorescence derivatization [26,27] and liquid chromatography with different mass spectrometry [28,29,30,31,32]. Of all the instrumental methods, the LC-MS system that combines the separation ability of liquid chromatography along with the sensitivity and specificity of detection from mass spectrometry and abandoned the additional derivation procedure of whole analysis process has gone mainstream for pesticide residue analysis.…”

Section: Introductionmentioning

confidence: 99%

Quantification and Confirmation of Fifteen Carbamate Pesticide Residues by Multiple Reaction Monitoring and Enhanced Product Ion Scan Modes via LC-MS/MS QTRAP System

et al. 2018

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In this research, fifteen carbamate pesticide residues were systematically analyzed by ultra-high performance liquid chromatography–quadrupole-linear ion trap mass spectrometry on a QTRAP 5500 system in both multiple reaction monitoring (MRM) and enhanced product ion (EPI) scan modes. The carbamate pesticide residues were extracted from a variety of samples by QuEChERS method and separated by a popular reverse phase column (Waters BEH C18). Except for the current conformation criteria including selected ion pairs, retention time and relative intensities from MRM scan mode, the presence of carbamate pesticide residues in diverse samples, especially some doubtful cases, could also be confirmed by the matching of carbamate pesticide spectra via EPI scan mode. Moreover, the fragmentation routes of fifteen carbamates were firstly explained based on the mass spectra obtained by a QTRAP system; the characteristic fragment ion from a neutral loss of CH3NCO (−57 Da) could be observed. The limits of detection and quantification for fifteen carbamates were 0.2–2.0 μg kg−1 and 0.5–5.0 μg kg−1, respectively. For the intra- (n = 3) and inter-day (n = 15) precisions, the recoveries of fifteen carbamates from spiked samples ranged from 88.1% to 118.4%, and the coefficients of variation (CVs) were all below 10%. The method was applied to pesticide residues detection in fruit, vegetable and green tea samples taken from local markets, in which carbamates were extensively detected but all below the standard of maximum residue limit.

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Section: Introductionmentioning

confidence: 99%

Quantification and Confirmation of Fifteen Carbamate Pesticide Residues by Multiple Reaction Monitoring and Enhanced Product Ion Scan Modes via LC-MS/MS QTRAP System

et al. 2018

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“…In order to monitor pesticide levels in the environment samples, various analytical methods have been developed including HPLC , GC , CE , and TLC . Among these methods, HPLC has been considered the most reliable due to its high sensitivity, simplicity, and applicability .…”

Section: Introductionmentioning

confidence: 99%

Determination of fungicides in sediments using a dispersive liquid–liquid microextraction procedure based on solidification of floating organic drop

Dong

Huang

2014

J of Separation Science

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A dispersive liquid-liquid microextraction procedure based on solidification of floating organic droplet has been investigated for the determination of fungicides (cyprodinil, difenoconazole, myclobutanil, and spiroxamine) in sediments by HPLC with diode array detection. In the overall extraction process, the extraction solvents can be separated easily from the sample solution, and the experiment time was shortened. Moreover, several parameters such as the type and volume of the extraction solvent and dispersive solvent, centrifugal speed, extraction time, and salt effect that affect the extraction efficiencies of the target fungicides were studied and optimized. Under the optimized conditions, the LOD for the target analytes were in the range of 0.1-0.5 μg/g. Satisfactory recoveries of the target analytes in the sediment samples were 81.00-99.00%, with RSDs (n = 5) that ranged from 1.8 to 6.5%. Finally, the simple, sensitive, and environmentally friendly method was successfully applied to determine the target fungicides in actual sediment samples.

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“…As one of the oldest chromatographic methods, TLC has been applied for analysis of enzyme reactions in a few off‐line (or off‐plate) studies recently, in which enzyme reactions are carried out in a sample vial and TLC technique is used only for separation and detection of the products and unreacted substrates . Alternatively, several interesting studies have reported qualitative on‐plate inhibition assays based on TLC technique . The TLC technique is a simple, easy‐to‐operate and low‐cost method in enzyme assay.…”

Section: Introductionmentioning

confidence: 99%

On-plate enzyme and inhibition assay of glucose-6-phosphate dehydrogenase using thin-layer chromatography

et al. 2015

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We performed on-plate enzyme and inhibition assays of glucose 6-phosphate dehydrogenase using thin-layer chromatography. The assays were accomplished based on different retardation factors of the substrates, enzyme, and products. All the necessary steps were integrated on-plate in one developing process, including substrate/enzyme mixing, reaction starting, and quenching as well as product separation. In order to quantitatively measure the enzyme reaction, the developed plate was then densitometrically evaluated to determine the peak area of the product. Rapid and high-throughput assays were achieved by loading different substrate spots and/or enzyme (and inhibition) spots in different tracks on the plate. The on-plate enzyme assay could be finished in a developing time of only 4 min, with good track-to-track and plate-to-plate repeatability. Moreover, we determined the Km values of the enzyme reaction and Ki values of the inhibition (Pb(2+) Cd(2+) and Cu(2+) as inhibitors), as well as the corresponding kinetics using the on-plate assay. Taken together, our method expanded the application of thin-layer chromatography in enzyme assays, and it could be potentially used in research fields for rapid and quantitative measurement of enzyme activity and inhibition.

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Effect of bromine oxidation on high-performance thin-layer chromatography multi-enzyme inhibition assay detection of organophosphates and carbamate insecticides

Cited by 19 publications

References 31 publications

Quantification and Confirmation of Fifteen Carbamate Pesticide Residues by Multiple Reaction Monitoring and Enhanced Product Ion Scan Modes via LC-MS/MS QTRAP System

Quantification and Confirmation of Fifteen Carbamate Pesticide Residues by Multiple Reaction Monitoring and Enhanced Product Ion Scan Modes via LC-MS/MS QTRAP System

Determination of fungicides in sediments using a dispersive liquid–liquid microextraction procedure based on solidification of floating organic drop

On-plate enzyme and inhibition assay of glucose-6-phosphate dehydrogenase using thin-layer chromatography

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