Development of human serum certified reference material for quantification of polychlorinated biphenyls

ABSTRACT

Human serum certified reference material (CRM), NMIJ CRM 7407-a, for the analysis of polychlorinated biphenyls (PCBs) was developed by the National Metrology Institute of Japan. A pool of commercially available human serum was used as a raw material of the CRM. This sample is in the form of a liquid comprising approximately 4 g stored in a cryogenic polypropylene vial. Homogeneity assessment was performed, and the material was homogeneous enough for PCB 118, PCB 138, PCB 153, and PCB 194: the relative uncertainties due to inhomogeneity were 2.5–10.5%. The results obtained from the stability assessment indicated that the target PCBs were stable: the relative uncertainties due to instability were 0–14.7%. The certification was carried out using two different types of GC columns for each target PCB to avoid interferences on GC separation; the certified values of the target PCBs (PCB 118, PCB 138, PCB 153, and PCB 194) were 9.7–129.8 ng/kg. This is the first frozen human serum CRM in which PCBs were determined by isotope dilution mass spectrometry.

KEYWORDS:

• Quality assurance/quality control
• certified reference material
• certification
• polychlorinated biphenyls (PCBs)
• human serum
• isotope dilution mass spectrometry (IDMS)

Acknowledgements

We would like to thank Dr. Y. Shibata, Dr. H. Nitta, Dr. S. F. Nakayama, Dr. T. Sano (National Institute for Environmental Studies, Japan), and Dr. J. Yoshinaga (Toyo University) for valuable discussions.

Disclosure statement

No potential conflict of interest was reported by the authors.