title: Evaluation of a multiresidue method for measuring fourteen chemical groups of pesticides in water by use of LC-MS-MS.
abstract: European Council Directive 98/83/EC on the quality of water intended for human consumption brought a new challenge for water-quality control routine laboratories, mainly on pesticides analysis. Under the guidelines of ISO/IEC 17025:2005, a multiresidue method was developed, validated, implemented in routine, and studied with real samples during a one-year period. The proposed method enables routine laboratories to handle a large number of samples, since 28 pesticides of 14 different chemical groups can be quantitated in a single procedure. The method comprises a solid-phase extraction step and subsequent analysis by liquid chromatography-mass spectrometry (LC-MS-MS). The accuracy was established on the basis of participation in interlaboratory proficiency tests, with encouraging results (majority |z-score| <2), and the precision was consistently analysed over one year. The limits of quantitation (below 0.050 microg L(-1)) are in agreement with the enforced threshold value for pesticides of 0.10 microg L(-1). Overall method performance is suitable for routine use according to accreditation rules, taking into account the data collected over one year.
authors.affiliation: IAREN-Water Institute of the Northern Region, Rua Dr. Eduardo Torres, 229, 4450-113, Matosinhos, Portugal.
authors.forename: J J
authors.initials: JJ
authors.lastname: Carvalho
authors.forename: P C A
authors.initials: PC
authors.lastname: Jerónimo
authors.forename: C
authors.initials: C
authors.lastname: Gonçalves
authors.forename: M F
authors.initials: MF
authors.lastname: Alpendurada