Development of certified reference materials of high-purity volatile organic compounds: purity assay by the freezing-point depression method

For accurate measurement of concentrations of substances by instrumental analysis, reliable calibration standards are needed. In Japan, national reference materials are supplied under the national standards dissemination system named the Japan Calibration Service System (JCSS). In JCSS, calibration standards for the analysis of environmental pollutants are supplied. For the traceability to the SI of reference materials for calibration in JCSS, the National Metrology Institute of Japan (NMIJ) is developing high-purity reference materials of volatile organic compounds (VOCs) as NMIJ CRMs. The freezing-point depression method, which has potential as a primary method of measurement, is employed for the determination of property value. In this paper, a development scheme of certified reference materials of high-purity VOCs is described.