Simultaneous determination of copper, lead, cadmium, zinc, and selenium in cow liver by differential pulse polarography

A fast and simple method was established for the determination of trace elements in liver. DP polarograms of wet digested liver samples were taken in acetate buffer, pH about 4, for lead, cadmium, and zinc determinations. For copper, addition of EDTA at pH 4 was needed for a better separation from the iron peak. Selenite ion was determined using the hydrogen catalytic peak after the addition of Mo(VI) to the same solution. Trace element levels were different for two separate sections of liver. For the first section (S1) the quantities were found to be 8.12 ± 0.21 mg g–1 Cu, 1.16 ± 0.12 mg g–1 Zn, 1.09 ± 0.11 mg g–1 Cd, 0.59 ± 0.07 mg g–1 Pb, and 2.05 ± 0.22 mg g–1 Se, in dry liver. For the second section (S2) the results were the same for selenium, but Cd was too small to be detected. The other trace element quantities were 0.48 mg g–1 Cu, 0.22 mg g–1 Pb, and 0.29 mg g–1 zinc. The validity of the method was demonstrated with a synthetic sample resembling liver composition. This method enabled the simultaneous determination of heavy trace elements such as copper, lead, cadmium, molybdenum, selenium, and zinc by using an inexpensive instrument and without any separation or pre-concentration procedures.Key words: cow liver, determination, differential pulse polarography, trace elements.