Development and Validation of an Analytical Methodology To Determine Deltamethrin Residues and Its Metabolites in Pine Products Using GC-QTOF-MS

A new analytical methodology has been proposed to determine deltamethrin and two of its main metabolites (3-phenoxybenzoic acid and 3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylic acid) in pine needle and pine nut samples, using gas chromatography coupled to quadrupole time-of-flight mass spectrometry. Two sample treatments were developed consisting of a solvent extraction for pine needles and a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) methodology for pine nuts, both followed by an additional cleanup step. The eco-friendliness and practicality of the methods were assessed using modified green analytical procedure index and blue applicability grade index, respectively. The method was validated in terms of selectivity, limits of detection (0.2–26 μg kg–1) and quantification (0.6–79 μg kg–1), linearity, matrix effect (< ±20%), trueness (recoveries 82–102%), and precision (relative standard deviation <9%). An analysis of 20 Spanish samples revealed that no residues were found in any of them.