Development and uncertainty estimation of cryogenic homogenization and static headspace–gas chromatography–mass spectrometry method for the simultaneous determination of twelve toxic volatiles in disposable menstrual products
Volatile organic compounds (VOCs) threaten the health of women who use disposable menstrual products (DMPs). In this study, we aimed to develop a simple and reliable analytical method using a cryogenic mill and static headspace–gas chromatography–mass spectrometry (HS-GC-MS) for the simultaneous determination of twelve toxic VOCs in DMPs, and estimate the measurement uncertainty of the method using the bottom-up approach to ensure the quality of analytical results. Static HS conditions for the direct thermal extraction of the target VOCs from the cryogenically ground sample powders were optimized in terms of extraction temperature and equilibrium time. The separation was achieved using a GC-MS equipped with a VF-624ms column. Cryogenic mill homogenized DMP into powder with 100-μm particles in scanning electron microscopy study. Sample powder was demonstrated to be homogenous as assessed by the homogeneity test. Validation studies showed that the method has reliable performance characteristics: linearity (R2 ≥ 0.9994), limit of quantification (LOQ, 8.4–50.5 ng g−1), precision (relative standard deviation ≤ 18.7%), and accuracy (recovery = 83.4–114.2%) for all the analytes. The proposed method was successfully applied to the commercial products of disposable sanitary pads and tampons. The content of styrene was the highest, followed by those of toluene, hexane, and ethylbenzene. The quantitative data exhibited acceptable precision, as evaluated using the intra-laboratory Horwitz ratio. The expanded uncertainties estimated at three concentration levels ranged from 6.4% to 77.9%. Our simple and reliable method will be useful for quality control testing or quantitative risk assessment and will contribute to resolving the safety issues associated with the risk of human exposure to trace volatile residues in DMPs.
