Development of an Analytical Scheme for the Determination of Pyrethroid Pesticides in Composite Diet Samples

Abstract

Analysis of an individual's total daily food intake may be used to determine aggregate dietary ingestion of given compounds. However, the resulting composite sample represents a complex mixture, and measurement of such can often prove to be difficult. In this work, an analytical scheme was developed for the determination of 12 select pyrethroid pesticides in dietary samples. In the first phase of the study, several cleanup steps were investigated for their effectiveness in removing interferences in samples with a range of fat content (1-10%). Food samples were homogenized in the laboratory, and preparatory techniques were evaluated through recoveries from fortified samples. The selected final procedure consisted of a lyophilization step prior to sample extraction. A sequential 2-fold cleanup procedure of the extract included diatomaceous earth for removal of lipid components followed with a combination of deactivated alumina and C(18) for the simultaneous removal of polar and nonpolar interferences. Recoveries from fortified composite diet samples (10 microg kg(-1)) ranged from 50.2 to 147%. In the second phase of this work, three instrumental techniques [gas chromatography-microelectron capture detection (GC-microECD), GC-quadrupole mass spectrometry (GC-quadrupole-MS), and GC-ion trap-MS/MS] were compared for greatest sensitivity. GC-quadrupole-MS operated in selective ion monitoring (SIM) mode proved to be most sensitive, yielding method detection limits of approximately 1 microg kg(-1). The developed extraction/instrumental scheme was applied to samples collected in an exposure measurement field study. The samples were fortified and analyte recoveries were acceptable (75.9-125%); however, compounds coextracted from the food matrix prevented quantitation of four of the pyrethroid analytes in two of the samples considered.

Analysis, occurrence, and toxic potential of pyrethroids, and fipronil in sediments from an urban estuary

“…It follows that the background associated with the sample matrix and the aforementioned co-elution issues account for the positive bias for ECD. Previous studies comparing different mass spectrometric configurations and operating modes (e.g., EI, NCI, and MS/MS) and ECD for analysis of pyrethroids concluded that sensitivity was similar but that the selectivity of NCI-MS and MS/MS was superior to ECD [8][9][10]17,22,23]. No such comparisons for fipronil were found in the literature.…”

Molecular Imprinting in Fluorescent Particle Stabilized Pickering Emulsion for Selective and Sensitive Optosensing of λ-Cyhalothrin

“…Thus, a rapid, sensitive, and selective analytical technique to monitor LC is crucial in order to safeguard public health, and it is now challenging to develop novel and efficient analysis platforms. Until now, pyrethroids detecting techniques mostly focus on chromatography separation, such as high performance liquid chromatography (HPLC), 4 gas chromatography (GC), 5 coupled column liquid chromatography with mass spectrophotometry (LC/MS), 6 and so forth. Despite their enhanced sensitive and specificity, these methods are time-consuming and require a tedious sample pretreatment.…”

Fluorescence-Based Sensing of Pesticides Using Supramolecular Chemistry

“…To address this challenge, one may look at successes with statistical-based analysis (linear discriminant analysis (Goschnick et al, 2007) and/or principal component analysis) (Wijayanti et al, 2019), and how researchers have used such tools to detect analyte mixtures for other applications. Alternatively, using additional methods to achieve separation prior to fluorescence-based analysis may also be possible, particularly if such methods can be made to operate effectively for on-site detection scenarios (Vonderheide et al, 2009). Additional challenges related to the use of fluorescence-based pesticide detection is that on-site fluorescence spectroscopy remains challenging.…”