TRACE DETERMINATION OF MANGANESE IN URINE BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY AND INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY

This paper describes a simple and sensitive method for the determination of manganese in human urine by graphite furnace atomic absorption spectroscopy (GFAAS), which includes sample preparation by microwave digestion. Matrix modifier combinations, the digestion power, pyrolysis, and atomization temperatures were optimized. A mixture of 5.0 mu g Pd(NO3)(2) and 3.2 mu g Mg(NO3)2 modifier presented the best performance. The optimal temperatures for pyrolysis and atomization were 1500 degrees C and 1950 degrees C, respectively. The GFAAS method was compared to inductively coupled plasma-mass spectrometry (ICPMS) for the determination of manganese in urine. Analytical figures of merit for GFAAS and ICP-MS were: accuracy (3.46%, 2.19%), precision (3.61%, 5.84%), LOD (0.109 mu g . L-1, 0.015 mu g . L-1), LOQ (0.327 mu g . L-1, 0.045 mu g . L-1), and recovery (80-100%, 74-89%). Both methods were employed for the determination of Mn in urine and the results were compared statistically.