Direct and simultaneous determination of copper, chromium, aluminum, and manganese in urine with a multielement graphite furnace atomic absorption spectrometer

A simple method was developed for the direct and simultaneous determination of copper, chromium, aluminum, and manganese in urine using a multielement GFAAS (Perkin-Elmer SIMAA6000). Pd was used as the chemical modifier along with a special purge gas (5% H-2 in Ar). A simple calibration curve method can be used (with 1:1 dilution). A standard reference material (Seronorm Trace Elements Urine) was used to find the optimal temperature program and to confirm the accuracy of the technique. The analyzed values were within 90-110% of the certified values. The relative standard deviations were 1.7, 1.5, 1.6, and 1.5% for these four elements and the detection limits were 0.08 mug L-1 for Cu, 0.05 mug L-1 for Cr, 0.06 mug L-1 for Al, and 0.06 mug L-1 for Mn. The recoveries of Cu, Cr, Al, and Mn from real urine samples were 100 5%, except for Cu (80%). The found values of Cu, Cr, Al, and Mn in a real urine sample were 14.3, 0.78, 18.9, and 0.06 mug L-1, respectively. Scanning electron micrographs were used to investigate the physical form of Pd on the surface of the platform in the graphite furnace. Use of 5% H-2 in Ar as the purge gas resulted in smaller and more uniformly distributed Pd particles (Pd particle diameters 0.4-0.6 mum using 5% H-2 in Ar compared to 0.4-1.2 mum using pure Ar), increasing the effect of the Pd chemical modifier and promoting the efficiency of atomization.