Combination of analyte protectants to overcome matrix effects in routine GC analysis of pesticide residues in food matrixes.
Analyte protectants were previously defined as compounds that strongly interact with active sites in the gas chromatographic (GC) system, thus decreasing degradation, adsorption, or both of coinjected analytes. In this study, we evaluated various combinations of promising analyte protectants for the volatility range of GC-amenable pesticides using GC/quadrupole mass spectrometry (MS) and 1-microL hot splitless injection for sample introduction. A mixture of ethylglycerol, gulonolactone, and sorbitol (at 10, 1, and 1 mg/mL, respectively, in the injected samples) was found to be the most effective in minimizing losses of susceptible analytes and significantly improving their peak shapes (due to reduction of peak tailing). When added to final sample extracts and matrix-free calibration standards alike, these analyte protectants induced a similar response enhancement in both instances, resulting in effective equalization of the matrix-induced response enhancement effect even after a large number of fruit and vegetable extract injections. As compared to matrix-matched standardization, the analyte protectant approach offers a more convenient solution to the problems associated with calibration in routine GC/MS analysis of pesticide residues and possibly other susceptible analyte types in diverse samples. Moreover, the use of analyte protectants also substantially reduced another adverse matrix-related effect caused by gradual build-up of nonvolatile matrix components in the GC system, thus improving ruggedness and, consequently, reducing need for frequent maintenance.
Mastovská
Katerina
K
Agricultural Research Service, Eastern Regional Research Center, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
Lehotay
Steven J
SJ
Anastassiades
Michelangelo
M
D001713:Biphenyl Compounds / Q000032:analysis; D002110:Caffeine / Q000737:chemistry; D004896:Erythritol / Q000737:chemistry; D005500:Follow-Up Studies; D005506:Food Contamination / Q000032:analysis*; D005638:Fruit / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D005947:Glucose / Q000031:analogs & derivatives / Q000737:chemistry; D005990:Glycerol / Q000031:analogs & derivatives / Q000737:chemistry; D001556:Hexachlorocyclohexane / Q000032:analysis; D009946:Organothiophosphorus Compounds / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis*; D011092:Polyethylene Glycols / Q000737:chemistry; D013012:Sorbitol / Q000737:chemistry; D013400:Sugar Acids / Q000737:chemistry
D001713:Biphenyl Compounds; D009946:Organothiophosphorus Compounds; D010573:Pesticide Residues; D013400:Sugar Acids; C013984:ethylidene glucose; C007895:gulonolactone; D002110:Caffeine; D011092:Polyethylene Glycols; C003117:phosalone; D013012:Sorbitol; D001556:Hexachlorocyclohexane; C004369:2-phenylphenol; D005947:Glucose; D005990:Glycerol; D004896:Erythritol