Optimization of new analytical procedures for the biological and environmental monitoring of occupational exposure to pesticides

Various analytical procedures for the simultaneous determination of 19 phytodrugs with different chemical nature (among which the abamectine, a natural product not easily quantifiable) were compared and optimized. Phytodrugs were extracted from: urinary matrix, for biological monitoring purposes; combined capture systems (PTFE filter and XAD-2 resin) and pads in fibre paper, for the evaluation of personal exposure (inhaling and dermal exposure, respectively). The analytical procedure was divided in two steps: extraction from complex matrices and detection method. For the extraction of phytodrugs from urine, two different techniques were compared: traditional liquid/liquid extraction and liquid extraction by using cartridges containing diatomaceous earths; besides, for each technique, the recovery efficiency of two extraction solvents was compared. Environmental matrices were treated analogously, by comparing the extraction efficiency of five different solvents. The examined phytodrugs were analysed both in LC/ESI-MS and GC/EI-MS, in SIM modality. Extraction recovery (both with ethyl acetate and a mix of ethylene chloride:ethylacetate) of investigated phytodrugs from urinary matrix varied from 73.2 to 117.2% in the case of diatomaceous earths, and from 81.7 to 123.9% for the liquid/liquid technique adopting ethylacetate. When the solvents mixture was used, a low recovery of hexythiazox (30.7%) was obtained, suggesting that the liquid/liquid extraction with ethylacetate was the optimal procedure for the simultaneous extraction of different phytodrugs from urine matrix. High extraction recovery from environmental matrices for all the investigated phytodrugs were obtained both with acetonitrile and acetone (65.3-115.8% and 59.8-114.3%, respectively). Detection methods comparison showed that the majority of the examined phytodrugs can be determined by GC/MS, except for fenbutatinoxide and abamectine, requiring LC/MS analysis. Detection limits were evaluated for urine and fibre paper, ranging from 0.466 to 25.60ng/ml and 0.020-0.306ng/cm2, respectively. Analytical accuracy was evaluated by analysing six calibration samples prepared both in urine (concentration ranges:0.05-1.66g/ml) and in pads (6-756ng/cm2). Obtained absolute values varied from 0.08 to 20% and 0.02 to 18% for all the concentration levels and the phytodrugs examined. Limits of detection and accuracy are being evaluated for the PTFE-XAD-2 capture system, as well as the procedures precision, and the proposed analytical methods are being applied to evaluate the occupational exposure to pesticides of subjects working in agricultural areas of South Italian regions. This research was supported by PON N. 12777, MIUR.