| Summary: | 碩士 === 中國醫藥大學 === 職業安全衛生學系碩士班 === 95 === Objective: The aims of this study was first to develop solid-phase micro- extraction gas chromatographic-mass spectrometric (SPME-GC /MS) method for investigating the exposed chemicals in the saliva of synthetic leather workers such as N, N-dimethylformamide (DMF), N-methylformamide (NMF), isopropyl alcohol (IPA), acetone (ACE) and methyl ethyl ketone (MEK), and the method validation between the SPME and liquid-liquid extraction (LLE) was conducted. Second, analyzing saliva samples of synthetic leather workers by SPME-GC/MS, and compare the concentrations in air sampling (DMF) and in urine (NMF) with that in saliva (NMF) for proposing an alternative analytical method for exposure.
Method: The method development was performed on analyzing the standards spiked into the pooled saliva of non-exposed adults. The analytical parameters investigated includes SPME fiber selection, sample volume, extraction temperature and time, desorption temperature and time, stirring speed, salt selection and amount, pH, and distribution constants. Then the concentration of N, N-dimethylformamide, N-methylformamide, isopropyl alcohol, acetone and methyl ethyl ketone in the saliva of workers were analyzed using SPME by GC/MS for exposure assessments.
Results: The CAR/PDMS fiber was chosen for the SPME method. We added 0.385g of NaCl into 1mL of saliva samples without pH adjustments, and then pre-incubate by stirring at 1000 rpm under 80°C for 180 minutes. After pre-incubation, headspace extraction was performed for 5minutes before a 3-minute desorption at 250°C by GC injector. All linear regression coefficients of all compounds reached 0.995, all recovery efficiencies were within the range of 100±10%, and the accuracy and precision were within ±10% range. The detection limits of SPME in all compounds (ACE: 0.002µg/mL, MEK: 0.003µg/mL, IPA: 0.003µg/mL, DMF: 0.04µg/mL, and NMF: 0.08µg/mL) were lower than the LLE. When confirming the efficacy of method with QC samples, the correlation between HS-SPME and LLE (ACE: 9.42 and 1.57 µg/mL, MEK: 12.88 and 6.44 µg/mL, IPA: 9.42 and 1.57 µg/mL, DMF: 94.4 and 9.44 µg/mL, and NMF: 300.9 and 30.09 µg/mL) was 0.993. While analyzing real samples, the correlation between NMF concentrations in saliva and in urine was significant 0.67(p<0.05); and the regression model for DMF concentration in air (A-DMF) and NMF concentrations in saliva (S-NMF) was S-NMF=1.24(A-DMF)-0.02 with a correlation of 0.82 (p<0.01), indicating that when DMF concentration in air increases 1ppm, the NMF concentration in saliva would increase by 1.24µg / mL.
Conclusion: The SPME-GC/MS method provides sufficient accuracy and precision within ±15% on the analysis of compounds in saliva from synthetic leather workers. This method could be operated easily, solvent- free, and with detection limits lower than LLE method. The saliva monitoring can be used as an alternative method to evaluate the worker''s exposure as well.
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