Simple and reliable method to simultaneously determine urinary 1‐ and 2‐naphthol using in situ derivatization and gas chromatography‐mass spectrometry for biological monitoring of naphthalene exposure in occupational health practice

• Published in: Journal of occupational health 2020-01, Vol.62 (1), p.e12144-n/a
• Main Authors: Takeuchi, Akito, Nakamura, Sadao, Namera, Akira, Kondo, Tomoaki, Onuki, Hiroyuki, Yamamoto, Shinobu, Okamura, Shingo, Nishinoiri, Osamu, Endo, Yoko, Miyauchi, Hiroyuki, Endo, Ginji
• Format: Article
• Language: English
• Subjects: Acetic anhydride; biological monitoring; Biological Monitoring - methods; Biomarkers; Biomonitoring; Calibration; Carcinogens; Chemical industry; Chromatography; Clinching; Correlation coefficient; Correlation coefficients; Exposure; Gas chromatography; Gas Chromatography-Mass Spectrometry - methods; gas chromatography‐mass spectrometry; Hexanes; Humans; Laboratories; Linearity; Mass spectrometry; Mass spectroscopy; Methods; Naphthalene; Naphthol; Naphthols - chemistry; Naphthols - urine; Occupational exposure; Occupational Exposure - analysis; Occupational health; Original; PCB; Phenolic compounds; Phenols; Polychlorinated biphenyls; Reproducibility; Scientific imaging; Spectroscopy; Temperature; Urine; Volumetric analysis
• ISSN: 1348-9585; 1341-9145; 1348-9585
• DOI: 10.1002/1348-9585.12144

Objectives The aim of this study was to develop and validate a simple and reliable gas chromatography‐mass spectrometry (GC‐MS) method to simultaneously determine urinary 1‐naphthol (1‐NAP) and 2‐naphthol (2‐NAP) for biological monitoring of occupational exposure to naphthalene. Methods NAPs were derivatized in situ with acetic anhydride after enzymatic hydrolysis, extracted with n‐hexane, and analyzed using GC‐MS. Validation of the proposed method was conducted in accordance with US Food and Drug Administration guidance. A final validation was performed by analyzing a ClinChek®‐Control for phenolic compounds. Results The linearity of calibration curves was indicated by a high correlation coefficient (>0.999) in the concentration range 1‐100 μg/L for each NAP. The limits of detection and quantification for each NAP were 0.30 and 1.00 μg/L, respectively. The recovery was 90.8%‐98.1%. The intraday and interday accuracies, expressed as the deviation from the nominal value, were 92.2%‐99.9% and 93.4%‐99.9%, respectively. The intraday and interday precision, expressed as the relative standard deviation, was 0.3%‐3.9% and 0.4%‐4.1%, respectively. The ClinChek® values obtained using our method were sufficiently accurate. Conclusions The proposed method is simple, reliable, and appropriate for routine analyses, and is useful for biological monitoring of naphthalene exposure in occupational health practice.