Comparison between methods for analysis of insecticides in human blood using gas chromatography-mass spectrometry and high performance liquid chromatography-mass spectrometry

摘要

For biomonitoring of exposure to insecticides, blood sample analysis is an effective tool to assess the instant exposure without concern with metabolism in the body. Analysis using high performance liquid chromatography-mass spectrometry (LCMS) has been popularly applied and considered superior to others because of the excellent sensitivity; nevertheless, use of LCMS is never cost-effective. We have developed a rapid, sensitive, and cost-effective whole blood extraction assay method to analyze insecticides in blood using gas chromatography-mass spectrometry (GCMS). In this study we analyzed blood samples using the developed GCMS and regular LCMS assay methods, and compared the results side by side to show the excellence of this GCMS method as alternative. The blood samples were prepared by spiking 9 insecticides, including carbamate, organophosphates and pyrethroids, to blood that was confirmed to be blank in advance. A total of 20 pairs of spiked blood samples were prepared with the concentration being set at 10 ug/L for each compound. Pretreatment of blood samples started with extraction of whole blood and serum for analysis on GCMS and LCMS, respectively; the organic extracts were dried and reconstituted with solvent prior to the respective analyses. Results derived from both methods indicated consistency between the two methods, showing less than 8% error within the expected concentration (10 u.g/L). Comparisons between data from GCMS and LCMS also demonstrated an excellent outcome of relative errors less than 8.2%, confirming that this GCMS method was as good as LCMS in performance, and was advantageous in terms of cost effectiveness. Keywords: biomonitoring, pesticides Imidacloprid Exposure in Crape Workers Lopez-Galvez N.', Wagoner R.', Canales R.', de Zapien J.l, Rosales C.', Beamer P.'; 'University of Arizona, Tuscon, AZ, USA Imidacloprid is a neonicotinoid insecticide commonly injected through agricultural drip irrigation systems to reduce the population of vine mealybugs in grape farms. In the present study, we evaluated the exposure to imidacloprid in 20 grape workers two weeks after imidacloprid injection in the irrigation system. We administered a questionnaire on work activities, exposure characteristics, and socio-demographics. We collected personal air and hand wipe samples to determine possible inhalation and dermal exposure. We collected urine samples to quantify metabolite concentrations and we measured hand surface temperatures. Most participants migrated from the state of Chiapas, Mexico, all participants had less than high school education and about half identified an indigenous language as their first language. Imidacloprid was not detected in air samples, but it was detected in 85% of the hand wipe samples (GM: 0.41 u.g/wipe). The majority of participants (75%) had detectable concentrations of imidacloprid as a parent compound in their urine (GM: 0.15 ug/g), and almost all of the participants (95%) had detectable concentrations of 5-hydroxy-lmidacloprid, a urine metabolite, (GM: 1.79 ug/g). There was a significant correlation (p < 0.001) of the imidacloprid concentration found in hand wipes with the concentrations found in urine (rho: 0.67, and 0.79 for imidacloprid and 5-hydroxy-lmidacloprid). Hands' temperature was significantly correlated (p < 0.05) with the pesticide concentration found on hands (rho: 0.70), and the urine biomarkers (rho: 0.68, and 0.60 for imidacloprid and 5-hydroxy-lmidacloprid). No levels of exposure via the inhalation route and higher levels via dermal route were found. Our results suggested that hand wipe can be use as less intrusive measurement to assess imidacloprid exposure in farm workers. Imidacloprid urine and hand wipes concentration were significantly higher during the summer than during the spring season. Further research needs to be conducted on microclimatic conditions to evaluate and reduce dermal pesticide exposure.