Comparison of negative chemical ionization and electron impact ionization in gas chromatography-mass spectrometry of endocrine disrupting pesticides.
The study of pesticide residues belonging to endocrine disrupting chemicals (EDCs) (23 analytes of different chemical classes--organochlorines, organophosphates, pyrethroids, dicarboximides, phtalamides, dinitroanilines, pyrazole, triazinone) in apple matrix with conventional capillary GC-NCI-MS (with methane as reagent gas) in comparison to EI ionization is presented. For sample preparation QuEChERS method was applied. The lowest calibration levels (LCLs) for all pesticides were determined in both modes. Calibration in the NCI mode was performed at the concentration levels from 0.1 to 500 microg kg(-1) (R(2) > 0.999) and for EI in the range from 5 to 500 microg kg(-1) (R(2) > 0.99). From LCLs the instrumental limits of detection (LODs) and quantification (LOQs) were calculated. Chemometric study of pesticide signals in two MS modes was performed. Repeatability of all measurements, expressed by the relative standard deviations of absolute peak areas was better than 10% for the majority of compounds. Significantly lower values were obtained for the NCI mode.
Institute of Analytical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, Bratislava 81237, Slovak Republic.
Renáta
R
Húsková
Eva
E
Matisová
Lubomír
L
Svorc
Ján
J
Mocák
Michal
M
Kirchner
D004583:Electrons; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D027845:Malus / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D010573:Pesticide Residues / Q000737:chemistry*; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D009930:Organic Chemicals; D010573:Pesticide Residues