Applying Tape Stripping Method and FTIR Spectroscopy to Estimate Dermal Exposure to Chemicals
Date Issued
2006
Date
2006
Author(s)
Chiu, Hsiao-Hui
DOI
en-US
Abstract
Objective: Tape stripping is a common method to estimate dermal exposure to chemicals because it is relatively noninvasive and easy to practice. Nevertheless, when sample is analyzed by gas chromatography, the method could be somewhat time-consuming. The goal of this study is to evaluate the feasibility of a novel approach by using an infrared transparent tape to conduct tape stripping sampling and analyzing the tape with Fourier Transform Infrared Spectroscopy transmission technique. This method can provide real-time dermal exposure estimates.
Materials and method: The chemical tested in this study are two commonly used insecticides, chlorpyrifos (CAS No. 2921-88-2) and captan, and one industrial material, Tripropylene glycol diacrylate (TPGDA) (CAS No.42978-66-5). Pure chlorpyrifos and TPGDA was diluted in 70% ethanol to high and low two concentration sets according to literature review of dermal exposure in field studies. The concentrations are 1.6µg/cm2 and 0.16µg/cm2 for chlorpyrifos, and 1.5µg/cm2and 0.4µg/cm2 for TPGDA. We verified the quantification ability of this method to: pure chemicals; chemical with human stratum corneum (SC); and two chemicals at the same time. And we enrolled ten volunteers and built the calibration curve for each one of them, to quantify the test samples of each subject by their own calibration curves and the combined calibration curves of the other nine people. The samples were obtained by 1) collecting background of the tapes which were precut to 3 cm×3 cm, fixed on magnetic holders, 2) pipetting certain amount of chemical solution onto the tapes, 3) collecting sample spectra after solvent was evaporated completely. SC on the tapes was collected by attaching the tape to forearm of the subject and stripped off gently. Background spectra were subtracted from sample spectra and the data were analyzed with partial least squares methods.
Results: The R2 of the calibration curves for pure chemicals are all > 0.99. The average prediction errors were 5.60±6.85% and 3.11±2.45% for low and high concentration chlorpyrifos, and 2.91±1.91% and 2.78±2.79% for low and high concentration TPGDA. The R2 of the calibration curves for chemicals with SC are all > 0.99. The average prediction errors were 13.01±10.03% and 4.54±2.91% for low and high concentration chlorpyrifos, and 7.86±7.82% and 5.21±5.11% for low and high concentration TPGDA. To quantified two chemicals without SC, the r-squares of loaded amount and measured amount were both 0.99 for chlorpyrifos and captan. The average % divergence was 3.46±2.26 for chlorpyrifos and 4.52±2.04 for captan. As for two chemicals with SC scenario, the r-squares of loaded amount and measured amount were 0.95 for chlorpyrifos and 0.97 for captan. The average % divergence was 10.89±10.58% for chlorpyrifos and 6.93±10.20 for captan. The samples of the ten subject quantified by the combined calibration curves of the other nine people had better results than those quantified by one’s own calibration curves(3.78±1.22% Vs.7.40 ± 4.18%). The results indicate that increase sample number of the calibration curve can reduce prediction error effectively, and the calibration curve built on the other people’s SC can quantify one’s samples competently.
Conclusion: This study demonstrates that this method would give better prediction results in high concentration, without SC conditions than in low concentration, with SC conditions. In general, FTIR transmission technique can quantify tape stripping samples accurately and rapidly.
Subjects
膠帶撕貼法
傅利葉紅外光光譜
陶斯松
tape stripping method
FTIR
chlorpyrifos
Type
thesis
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