title: Development and Validation of a Multiresidue Method for the Determination of Pesticides in Dry Samples (Rice and Wheat Flour) Using Liquid Chromatography/Triple Quadrupole Tandem Mass Spectrometry.
abstract: A rapid and sensitive multiresidue method was developed and validated for the determination of around 100 pesticides in dry samples (rice and wheat flour) by ultra-performance LC coupled to a triple quadrupole mass analyzer working in tandem mode (UPLC/QqQ-MS/MS). The sample preparation step was optimized for both matrixes. Pesticides were extracted from rice samples using aqueous ethyl acetate, while aqueous acetonitrile extraction [modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method] was used for wheat flour matrixes. In both cases the extracts were then cleaned up by dispersive solid phase extraction with MgSO4 and primary secondary amine+C18 sorbents. A further cleanup step with Florisil was necessary to remove fat in wheat flour. The method was validated at two concentration levels (3.6 and 40 μg/kg for most compounds), obtaining recoveries ranging from 70 to 120%, intraday and interday precision values≤20% expressed as RSDs, and expanded uncertainty values≤50%. The LOQ values ranged between 3.6 and 20 μg/kg, although it was set at 3.6 μg/kg for the majority of the pesticides. The method was applied to the analysis of 20 real samples, and no pesticides were detected.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Grande-Martínez
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Arrebola
authors.forename: Laura Díaz
authors.initials: LD
authors.lastname: Moreno
authors.forename: José Luis Martínez
authors.initials: JL
authors.lastname: Vidal
authors.forename: Antonia Garrido
authors.initials: AG
authors.lastname: Frenich
mesh_terms: D000085:Acetates / Q000737:chemistry; D000097:Acetonitriles / Q000737:chemistry; D000327:Adsorption; D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods; D005433:Flour / Q000032:analysis*; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D006801:Humans; D057230:Limit of Detection; D015588:Observer Variation; D012275:Oryza / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis*; D052616:Solid Phase Extraction / Q000295:instrumentation / Q000379:methods; D012997:Solvents / Q000737:chemistry; D013048:Specimen Handling / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D014908:Triticum / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000085:Acetates; D000097:Acetonitriles; D010573:Pesticide Residues; D012997:Solvents; D014867:Water; C007650:ethyl acetate; C032159:acetonitrile