Preparation and certification of lyophilized human urine for trace metals reference material in China

The preparation of lyophilized human urine certified reference material (CRM) was established on the basis of literature in other countries and domestic conditions. The homogeneity and stability of the CRM accord with the stipulations. The certified values were determined by 14 high level laboratories in China using nine methods with different principles and have been examined by the National Institute for Occupational Safety and Health (NIOSH) using Inductively Coupled Plasma--Mass Spectrometry (ICP-MS). This CRM has been approved as first grade national reference material. It can be used in quality control of routine analysis, test of new methods, and as standard material for calibration of analytical instruments and as certified reference material for quantity transmission and analysis arbitration.