Multi-residue method for the determination of organochlorine pesticides in fish feed based on a cleanup approach followed by gas chromatography–triple quadrupole tandem mass spectrometry

Highly-Selective Analytical Strategy for 90 Pesticides and Metabolites Residues in Fish and Shrimp Samples

The analysis of pesticide residues in aquatic products is challenging due to low residue levels and the complex matrix interference. In this study, we developed a simple, fast method for the trace analysis of 90 pesticides and metabolites in aquatic products. The analytes covered a wide polarity range with log Kow (log octanol-water partition coefficient) ranging from -1.2 to 6.37. Grass carp (Ctenopharyngodon idellus) and prawn (Penaeus chinensis) samples were chosen to validate the quantification method. The samples were extracted by 0.2% formic-acetonitrile, cleaned by solid-phase extraction (PRiME HLB), and analyzed by high performance liquid chromatography-tandem mass spectrometry. The results showed good linearities for the analytes and were observed in the range of 0.05-50 μg/L. The recoveries of the method were within 50.4-118.6%, with the relative standard deviations being lower than 20%. The limits of quantifications (LOQs) of the method were in the range of 0.05-5.0 μg/kg, which were superior to values compared with other research. The developed method was applied to detect pesticide residues in prawn samples from eastern coastal areas of China. Three herbicide residues of diuron, prometryn, and atrazine were detected in prawn samples. The method was sensitive and efficient, which is of significance in expanding the screening scope and improving the quantitative analysis efficiency in aquatic products.

Magnetic polymer particles as a highly efficient and facile cleanup adsorbent for multi-pesticide residues analysis in aquatic products

A novel and efficient sample pretreatment procedure using magnetic particles was exploited for the determination of multi-pesticide residues in aquatic products. The magnetic adsorbent was prepared using divinyl benzene and N-vinyl pyrrolidone as functional monomers modified on the Fe₃O₄ @SiO₂. The obtained magnetic adsorbent, octadecylsilane sorbents, and graphitized carbon black were employed as effective adsorbents to remove matrix interferences in aquatic products, and their dosages were optimized. Satisfactory levels of accuracy and precision were procured under optimum conditions. The method limits of quantification ranged from 0.1 to 2.0 μg/kg. The analytical accuracy of the developed method for the analysis of multi-pesticide residues in freshwater and seafood products was validated. It was found to be suitable for the analysis of multi-pesticide residues in different types of aquatic products. Additionally, the method was successfully applied for the analysis of pesticide residues in fish samples obtained from aquaculture plants located in Zhejiang Province, China. The detected concentrations of pesticides ranged from 0.14 to 0.95 μg/kg. In general, this method shows promising application prospects for the rapid determination of multi-pesticide residues in aquatic products.

Fast gas chromatographic residue analysis in animal feed using split injection and atmospheric pressure chemical ionisation tandem mass spectrometry

Significant speed improvement for instrumental runtime would make GC–MS much more attractive for determination of pesticides and contaminants and as complementary technique to LC–MS. This was the trigger to develop a fast method (time between injections less than 10 min) for the determination of pesticides and PCBs that are not (or less) amenable to LC–MS. A key factor in achieving shorter analysis time was the use of split injection (1:10) which allowed the use of a much higher initial GC oven temperature. A shorter column (15 m), higher temperature ramp, and higher carrier gas flow rate (6 mL/min) further contributed to analysis-time reduction. Chromatographic resolution was slightly compromised but still well fit-for-purpose. Due to the high sensitivity of the technique used (GC–APCI-triple quadrupole MS/MS), quantification and identification were still possible down to the 10 μg/kg level, which was demonstrated by successful validation of the method for complex feed matrices according to EU guidelines. Other advantages of the method included a better compatibility of acetonitrile extracts (e.g. QuEChERS) with GC, and a reduced transfer of co-extractants into the GC column and mass spectrometer.

Determination of pesticide residues in fish tissues by modified QuEChERS method and dual-d-SPE clean-up coupled to gas chromatography-mass spectrometry

The aim of this research was to modify the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for the determination of organochlorine and organophosphate pesticides in fatty animal matrices such as fish muscle tissues of carp and sturgeon collected from Carp Valley, Lesser Poland. Pesticides extraction effectiveness was evaluated at 0.030 mg kg(-1) spiking level and efficiency of the dispersive-solid-phase extraction (d-SPE) clean-up step was evaluated by comparison testing two different d-SPE clean-up stages, first the addition of the d-SPE sorbent combination (PSA + SAX + NH2), and secondly the addition of C18 after extracts enrichment with the d-SPE sorbent combination (PSA + SAX + NH2), introducing a novel concept of clean-up named dual-d-SPE clean-up. Analysis of pesticide residues was performed by Gas Chromatography Quadrupole Mass Spectrometry (GC/Q-MS) working in selected-ion monitoring (SIM) mode. Linear relation was observed from 0 to 200 ng mL(-1) and determination coefficient R(2) > 0.997 in all instances for all target analytes. Better recoveries and cleanliness of extracts in both samples, carp and sturgeon tissues, were obtained after C18 addition during the dual-d-SPE clean-up step. Recoveries were in the range 70-120%, with relative standard deviation lower than 10% at 0.030 mg kg(-1) spiking level for most pesticides. LODs ranged 0.001-0.003 mg kg(-1), while LOQs ranged 0.004-0.009 mg kg(-1). The proposed method was successfully applied analyzing pesticide residues in real carp and sturgeon muscle samples; detectable pesticide residues were observed, but in all of the cases contamination level was lower than the default maximum residue levels (MRLs) set by the European Union (EU), Regulation (EC) N 396/2005.

Monitoring of systemic exposure to plant protection products and DNA damage in orchard workers

The systemic exposure of plum tree growers and operators to plant protection products (PPPs) and effects on DNA were assessed. Specifically, a GC-MS/MS method was developed and validated for the analysis of serum samples for the presence of seven active substances of PPPs. The analytical results verified the presence of myclobutanil, propargite, cypermethrin and deltamethrin in 7 out of 19 serum samples. The incidence of DNA damage was monitored using the single cell electrophoresis assay (comet assay). A paired Student's t-test revealed a statistically significant increase of SSBs in the blood samples collected at the end of the cropping period as compared to the samples collected from the same subjects before the start of PPPs application period. Moreover, the group of seven subjects with detectable serum pesticides levels revealed statistically significant increase of SSBs as compared to the group of subjects with no detectable PPP levels. The results of the present study demonstrate that the agriculture workers may exhibit detectable level of systemic exposure to the applied PPPs which are correlated to increased DNA damage during the cultivation period.