Development of an analytical method based on microwave-assisted extraction and solid phase extraction cleanup for the determination of organochlorine pesticides in animal feed

Abstract

A method to determine 21 organochlorine pesticides in animal feed samples using microwave assisted extraction and solid phase extraction cleanup was optimised regarding its main parameters. After extraction with hexane-acetone (50:50), three different sorbents (alumina/ENVI-Florisil, ENVI-Carb and ENVI-Carb II/PSA) were assayed for the cleanup step. Analytes were eluted with hexane-ethyl acetate (80:20) and determined by gas chromatography and electron capture detection followed by gas chromatography-mass spectrometry. ENVI-Carb and ENVI-Carb II/PSA provided colourless eluates but fewer interferent compounds were found in ENVI-Carb II/PSA chromatograms, so this system was selected to carry out the purification of the extracts. The analytical recoveries obtained with this method were close to 100% in most cases with relative standard deviations lower than 10%. These percentages were similar to those obtained with the Soxhlet extraction procedure, which shows the method suitable for the determination of organochlorine pesticides in animal feed material. The method was also validated with the analysis of a certified reference material (CRM-115 BCR), and the results obtained were in good accordance with the certified values.

Extraction of Organochlorine Pesticides from Bee Pollen by Matrix Solid-Phase Dispersion: Recovery Evaluation by GC–MS and Method Validation

“…Primary secondary amine (PSA) and graphitized carbon (GCN) were tested as co-columns for the clean up step because of their strong affinities for pigments (chlorophyll, carotenoids), sterols, sugars, fatty acids, and other compounds [31]. In general, with PSA and GCN, the MSPD extracts were cleaner (no color) than those obtained without co-columns; this agrees with our previous work on organophosphorus pesticides in propolis [29].…”

Determination of acetanilide herbicides in cereal crops using accelerated solvent extraction, solid‐phase extraction and gas chromatography‐electron capture detector

“…The highest cleanup ability of GCB/PSA cartridge may be the result of the following: the GCB/PSA cartridge is a dual‐layer SPE tube that contains both GCB (upper layer) and PSA (lower layer) separated by a polyethylene frit. GCB layer can remove most of the visible plant pigment but do little to eliminate the fatty acid; however, PSA layer significantly retains fatty acids, organic acids, sugars and some polar pigments 32–34; the combination of GCB and PSA was found to provide the best clean‐up of total matrix compounds in this study and it was selected for the purification procedure.…”

“…ASE was chosen as the extraction method because this technique offers advantages such as amenable to automation, require short extraction times, reduce organic solvent consumption and reduce cost of analysis. However, lipid compounds as well as other molecules present in the samples are co‐extracted with the analyzed pesticides so a cleanup procedure is recommended to diminish the presence of interference in the final extract, which can affect chromatographic performance, resulting in analytical inaccuracies and decreased instrumental precision 32, 33. Cleanup assays were carried out in order to find the best sorbent for the SPE.…”

Analysis of Fluoroquinolones in Animal Feed Based on Microwave-Assisted Extraction by LC–MS–MS Determination

“…Some antibiotics have been reported to be extracted from feed by MAE [16,17]. In MAE, microwaves heat the sample directly without heating the vessel.…”