Potentiality of Gas Chromatography−Triple Quadrupole Mass Spectrometry in Vanguard and Rearguard Methods of Pesticide Residues in Vegetables

• Published in: Analytical chemistry (Washington) Vol. 77; no. 14; pp. 4640 - 4648
• Main Authors: Garrido Frenich, Antonia, González-Rodríguez, Manuel J, Arrebola, Francisco J, Martínez Vidal, José L
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.07.2005
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography; Exact sciences and technology; Food Contamination - analysis; Gas chromatographic methods; Gas Chromatography-Mass Spectrometry - methods; Mass spectrometry; Pesticide Residues - analysis; Pesticides; Spectrometric and optical methods; Vegetables; Vegetables - chemistry; Trace analysis; Standard addition method; Vegetables; Pesticides; Matrix effect; Quadrupole spectrometer; Gas chromatography; Sample preparation; Residue; Sodium sulfate; Mass spectrometry MS/MS; Time analysis; Mass spectrometry; Comparative study; Quantitative analysis
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac050252o

A new analytical strategy for the screening and confirmation/quantification of multiclass pesticide residues in vegetables has been established and validated. No complicated sample preparation was needed, but only a simple and rapid extraction using ethyl acetate and sodium sulfate, which required no cleanup. The approach is based on the use of the triple quadrupole (QqQ) mass spectrometry (MS) as detection system in gas chromatography (GC). In a first step, a GC-QqQ-MS screening method, which monitors only one MS/MS transition by compound, allows the identification of ∼130 pesticides in 11.6 min. In this way, the differentiation between negative and potentially nonnegative samples is carried out. In the second step, the nonnegative samples are reanalyzed by the GC-QqQ-MS confirmation/quantification method, which monitors two or three MS/MS transitions by compound. Confirmation of pesticides was based on the comparison of intensity ratios for the main ions in samples with those obtained on the same day from the standard in a matrix containing the pesticides at a preestablished concentration level. Quantification of the identified and confirmed pesticides was based on the addition standard method, which avoids matrix effect. The proposed analytical strategy allowed a reliable identification and confirmation of the target pesticides at trace levels, reducing analysis time and increasing sample throughput in routine analytical laboratories.