Evaluation of matrix effect on the GC response of eleven pesticides by PCA

Abstract

a b s t r a c tThe components of seven matrices in the analysis of 11 pesticides by GC-ECD were analysed. The matrix effect was calculated based on the changing of chromatographic response of the analyte in the presence of co-extractives of the matrices in the organic phase obtained by solid-liquid and liquid-liquid extraction with partition at low temperature (ESL-PBT and ELL-PBT), in relation to the response of it in the pure solvent. It was used the Principal Component Analysis (PCA) in evaluating the results obtained for the percentages of the matrix effect. The tomato, grape and pineapple matrices caused greater matrix effect and were grouped. The other matrices such as apple, water and potato caused small matrix effect. For most pesticides the soil matrix caused negative matrix effect. The influence of pH of the samples on the matrix effect was also evaluated showing not to have a direct effect on the phenomenon.

Analysis of tomato matrix effect in pesticide residue quantification through QuEChERS and single quadrupole GC/MS

“…This fact could probably be associated with the presence of coextractives compounds, which reduced these pesticides ionization. Similar results had been reported for permethrin in tomato matrix but using Electron Capture Detector (ECD) and solid liquid partition (de Sousa et al, 2012); while contrary to our results, it have been reported the existence of tomato matrix effect for iprodione with Nitrogen and Phosphorous Detector (NPD) and ECD detection, although the matrix effect extent was not informed (Guerrero, 2003). Negative matrix effect had been found also, for other pesticides and matrices, like apple (Ahumada et al, 2010).…”

“…Determination of matrix effect. Different test for the determination of matrix effect and matrix effect extent had been reported in the literature (Hajšlová et al, 1998;Guerrero, 2003;Kruve et al, 2009;Ferrer et al, 2011;Moura et al, 2011;Ahumada and Zamudio, 2011;de Sousa et al, 2012;Kwon et al, 2012), some of them were tested in this scope, besides the ANOVA procedure.…”

“…Both curves could be prepared with or without internal standard (Guerrero, 2003;Ferrer et al, 2011;Moura et al, 2011). Also, it is had been reported for this purpose other statistical procedures like ANCOVA (Ahumada and Zamudio, 2011); or Principal Components Analysis (PCA) (de Sousa et al, 2012). Besides that, various studies report the extent of matrix effect (enhancement or suppression) (Kruve et al, 2009), and the matrix effect percentage (% ME) (Economou et al, 2009;Ahumada et al, 2010).…”

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

“…Grapes have a high sugar content 27 besides others co-extractives that may remain solubilized in the organic extracts being responsible for increase gas chromatographic signal and sensitivity. 40 The validation parameters achieved with the proposed method are comparable with those already published. Limits of detection and quantification (0.006-0.02 mg kg −1 ) shown to be lower than those found by Alves et al 21 (3.75-9.47 mg kg −1 ) and You et al 17 (0.5-5.0 mg kg −1 ), even using a concentration technique as solid phase extraction (SPE) and ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet (UA-DLLME-SFO), respectively.…”

Atmospheric pressure gas chromatography–time-of-flight-mass spectrometry (APGC–ToF-MS) for the determination of regulated and emerging contaminants in aqueous samples after stir bar sorptive extraction (SBSE)

“…Ionization efficiency did not decrease dramatically in any environmental sample, only up to 30% in the dirtiest extracts corresponding to effluent water samples. According to De Sousa and co-workers [39], presence of other co-eluting compounds could also affect the retention time of the analytes, although this was not observed in our case.…”