Arsenic speciation in human urine reference materials using high-performance liquid chromatography with inductively coupled plasma mass spectrometricdetection

Six arsenic compounds including arsenocholine, arsenobetaine, dimethylarsin ic acid, methylarsonic acid, arsenous acid and arsenic acid were separated by high-performance liquid chromatography (HPLC) on a Hamilton PRP-X100 ani on-exchange column using isocratic elution and detected by inductively coup led plasma mass spectrometry (ICP-MS). This analytical procedure was applie d to the speciation of arsenic compounds in human urine. The influence of u rine matrix on the separation of arsenic compounds was evaluated and the de termination of arsenic compounds was not hampered by the ArCl interference which has often been encountered in ICP-MS. Three human urine reference mat erials, SRM 2670 normal level, SRM 2670 elevated level and Lyphocheck urine metal control 1, were analyzed with respect to arsenic compounds by HPLC-I CP-MS. The results were found to be in good agreement with the certified to tal arsenic concentration in the reference materials. Six arsenic compounds were detected. Arsenobetaine was found to be present in all of the investi gated human urine reference materials.