Influence of pH and Matrix Components in the Chromatographic Response of Pesticides

“…4, a trend was observed in which some pesticides with longer retention times showed higher matrix effects. Sousa et al (21) reported that similar results were observed in pesticides eluted at the end of a chromatographic run. Sanchez-Brunete et al (17) suggested that the pyrethroid pesticides, such as cyhalothrin and cypermethrin, have a high molar mass (over 400 g/mol), which make them remain at the GC inlet longer and delay their volatilization when injected into the GC.…”

Section: Resultsmentioning

confidence: 62%

“…Matrix effects during GC analysis of various kinds of pesticides have been reported for various matrices by several laboratories, but most of them were conducted with no clean-up processes in order to exclude the influences of purification on matrix effects (5)(6)(7)(8)(9)(10)(11)(12)(13). The factors influencing matrix effects and various methods of diminishing matrix effects were also proposed by several researchers (14)(15)(16)(17)(18)(19)(20)(21). During pesticide analysis using GC, non-volatile matrix components coexisting with analytes in an injected sample usually accumulate in the GC inlet and/or in the front part of a column, masking active sites in the GC liner, and decreasing the loss of susceptible and thermolabile pesticides (18).…”

Section: Introductionmentioning

confidence: 99%

Determination of matrix effects occurred during the analysis of organochlorine pesticides in agricultural products using GC-ECD

Kim

Lee

Park

et al. 2016

Food Sci Biotechnol

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Matrix effects observed during the multiresidue analysis of seven organochlorine pesticides in six different agricultural products with GC-ECD were assessed. The presence of matrix coextractives, a major cause of observed matrix effects, directly and/or indirectly influenced the chromatographic responses of some pesticides. Two types of external calibrations, solvent calibration (SC) and matrixmatched calibration (MC), were used to assess matrix effects. Greater matrix effects were observed at the lower concentrations of each pesticide. The extent of matrix effects varied unpredictably with matrix type. Among the analyzed pesticides, iprodione, cyhalothrin, and cypermethrin exhibited greater matrix effects (>150%) for almost all matrices. The pesticide recovery rates obtained with MC were not statistically different from a 100% recovery rate in most samples, which indicates that MC may diminish the overestimates occurred due to matrix effects in GC analysis.

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“…5 Natural pigments does not interfere directly in the chromatographic analysis of pesticides, but can remained in the injector liner and the chromatographic column, shortening the useful life of this devices. 37 In the clean-up step, it was found that GCB provided an adequate clean-up, resulting in almost colorless extracts. In contrast to GCB, C18 and alumina provided the most colorful extracts, as can be seen in Figure 3.…”

Section: Extraction and Clean-up Optimizationmentioning

confidence: 99%

Evaluation of QuEChERS Sample Preparation and Gas Chromatography Coupled to Mass Spectrometry for the Determination of Pesticide Residues in Grapes

Volpatto

Wastowski

Bernardi

et al. 2016

Journal of the Brazilian Chemical Society

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An effective analytical method for pesticides multiresidue determination in grape samples was developed and validated. A modified quick, easy, cheap, effective, robust and safe (QuEChERS) method was used to extract the target compounds. Several sorbent materials were tested for the clean-up step using dispersive solid phase extraction (d-SPE) and Florisil ® was selected. Samples extracts were evaporated before injection in the gas chromatography with mass spectrometry (GC-MS) system in order to improve detectability. Recoveries from blank samples spiked at 0.04, 0.3 and 1.0 mg kg −1 ranged from 95 to 102% with relative standard deviation (RSD) from 1.3 to 19.7%. Method limits of detection (LODm) and quantification (LOQm) ranged from 0.006 to 0.012 and 0.02 to 0.04 mg kg −1 , respectively. The positive matrix effect caused an increase in the peak areas of all compounds and matrix matched calibration curve linearity (coefficient of determination, r 2 ) was higher than 0.98 for all target analytes. The validated method was successfully applied for the determination of 19 pesticides in grape samples.

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Influence of pH and Matrix Components in the Chromatographic Response of Pesticides

Cited by 12 publications

References 18 publications

Quantitative Analysis

Quantitative Analysis

Determination of matrix effects occurred during the analysis of organochlorine pesticides in agricultural products using GC-ECD

Evaluation of QuEChERS Sample Preparation and Gas Chromatography Coupled to Mass Spectrometry for the Determination of Pesticide Residues in Grapes

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