Evaluation of relevant time-of-flight-MS parameters used in HPLC/MS full-scan screening methods for pesticide residues.
An automatic screening method based on HPLC/time-of-flight (TOF)-MS (full scan) was used for the analysis of 103 non-European fruit and vegetable samples after extraction by the quick, easy, cheap, effective, rugged, and safe method. The screening method uses a database that includes 300 pesticides, their fragments, and isotopical signals (910 ions) that identified 210 pesticides in 78 positive samples, with the highest number of detection being nine pesticides/sample. The concentrations of 97 pesticides were <10 microg/kg, 53 were between 10 and 100 microg/kg, and 60 were at a concentration of >100 microg/kg. Several parameters of the automatic screening method were carefully studied to avoid false positives and negatives in the studied samples; these included peak filter (number of chromatographic peak counts) and search criteria (retention time and error window). These parameters were affected by differences in mass accuracy and sensitivity of the two HPLC/TOF-MS systems used with different resolution powers (15 000 and 7500), the capabilities of which for resolving the ions included in the database from the matrix ions were studied in four matrixes, viz., pepper, rice, garlic, and cauliflower. Both of these mass resolutions were found to be satisfactory to resolve interferences from the signals of interest in the studied matrixes.
University of Almería, Pesticide Residue Research Group, 04120, La Cañada de San Urbano, Almería, Spain.
Milagros
M
Mezcua
Octavio
O
Malato
Maria Angeles
MA
Martinez-Uroz
Ana
A
Lozano
Ana
A
Agüera
Amadeo R
AR
Fernández-Alba
D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005638:Fruit / Q000737:chemistry; D010573:Pesticide Residues / Q000032:analysis*; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D014675:Vegetables / Q000737:chemistry
D010573:Pesticide Residues