An Inter-Laboratory Comparison for the Urinary Acrolein Biomarker 3-Hydroxypropyl-Mercapturic Acid (3-HPMA)

• Published in: Beiträge zur Tabakforschung international Vol. 27; no. 5; pp. 65 - 76
• Main Authors: Scherer, Gerhard, Heller, Wolf-Dieter, McEwan, Michael, Göen, Thomas, Joza, Peter, Liu, Nan, Newland, Kirk, Schettgen, Thomas, Wang, Sheng, Sohn, Hyung-Ok, Troude, Valerie, Yuki, Dai, Zheng, Saijing, Zhou, Guojun
• Format: Journal Article
• Language: English
• Published: De Gruyter Open 01.01.2017
• Subjects: 3-hydroxypropyl-mercapturic acid (3-HPMA); Inter-laboratory comparison; inter-laboratory variation; intra-laboratory variation; repeatability; reproducibility
• ISSN: 1612-9237
• DOI: 10.1515/cttr-2016-0006

An inter-laboratory comparison study on the acrolein biomarker of exposure 3-hydroxypropyl-mercapturic acid (3-HPMA) with 12 laboratories from 7 globally distributed countries was performed. The laboratories received coded triplicates of 4 spiked and lyophilized urine samples (LU, 12 samples) as well as 5 authentic urine pool samples (PU, 15 samples) covering the 3-HPMA concentration range from background (non-smoking) to heavy smoking levels for analysis by using their own (in-house) analytical method. All laboratories applied liquid chromatography with tandem mass spectrometry (LC-MS/MS), with most of them (10 of 12) using solid phase extraction (SPE) as sample work-up procedure. The intra-laboratory variation (indicating repeatability) was determined by calculating the standard deviation (s ) and the coefficient of variation (CV ) of the triplicates, whereas the inter-laboratory variation (indicating reproducibility) was determined by calculating the standard deviation between laboratories (s ) and the corresponding coefficient of variation (CV ). After removal of outlier samples or laboratories, the mean CV values for LU and PU test samples ranged from 2.1–3.6% (mean: 2.8%) and 2.4–3.7% (mean: 3.3%), respectively, indicating good repeatability for the determination of 3-HPMA in both sample types. CV for LU and PU test samples ranged from 9.1–31.9% (mean: 18.8%) and 13.9–27.0% (mean: 18.5%), respectively, indicating limited reproducibility in 3-HPMA analysis for both sample types. Re-calculation of the PU results by applying an embedded calibration (EC), derived from the reported peak areas for the LU test samples, somewhat improved the CV values (range: 9.6–28.8%, mean: 16.7%). It is concluded that the intra-laboratory variation (repeatability) in the determination of 3-HPMA in urine is in general acceptable in the participating laboratories, while the inter-laboratory variability requires further improvement. The relatively small reduction in the inter-laboratory variability (s and CV ) by applying an EC suggests that other methodological factors than the standard reference material for 3-HPMA have to be addressed to achieve further improvement in reproducibility.