Abstract:

 Objective · To compare urine sample collection methods for measuring urinary concentrations of phenolic endocrine disrupting chemicals including bisphenol A (BPA), triclosan (TCS), and 4-n-nonylphenol (4-n-NP) in pregnant women.  Methods · Urine samples were collected from women at late pregnancy by two methods: urine catheter and collection bag (n=176), urine collecting containers made of polypropylene (PP) (n=642). Urinary concentrations of BPA, TCS and 4-n-NP were measured with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. Confirmation experiment used PP containers, urine catheter and collection bags, as well as low-density polyethylene (LDPE) tubes and glass containers as both negative controls to collect urine samples from each of the 5 women.  Results · Geometric mean (GM) of urinary BPA concentration collected by urine catheter and collection bags was 82.5 ng/mL (95% CI 71.4-95.4 ng/mL), which was 63 times higher than that from PP containers (GM 1.3 ng/mL; 95% CI 1.3-1.5 ng/mL). Concentrations of urinary 4-n-NP and creatinine were similar between two collection methods. Confirmation experiment showed that urinary BPA concentration collected by urine catheter and collection bags was much higher than those collected by other three methods.  Conclusion · In collection of urine samples for measuring phenolic chemicals, PP urine collection container as well as LDPE containers are adequate for use in epidemiologic studies, but urine catheter and collection bag is not.

Key words: pregnant women, urine sample collection methods, material of urine collecting container, bisphenol A, triclosan, 4-n-nonylphenol