Anal. Chem. 1987, 59,2264-2269
2264
Electrochemical Preconcentration of Metals Using Mercury Film Electrodes Followed by Electrothermal Vaporization into an Inductively Coupled Plasma and Determination by Atomic Emission Spectrometry Henryk Matusiewicz*' Elemental Analysis Research Center, U.S. Food a n d Drug Administration, 1141 Central Parkway, Cincinnati, Ohio 45202
Judith Fish and Tadeusz Malinski* Department of Chemistry, Oakland University, Rochester, Michigan 48309-4401
The production and use of mercury film electrodes for matrlx separation and preconcentration of trace metals from blologlcal materlals prior to thelr determlnatlon by Inductively coupled plasma atomic emlssion spectrometry (ICP-AES) are descrlbed. Separatlon and preconcentration are achleved by controlled potentlal electrolysls on mercury-plated, glassy carbon electrodes. Electrodes wlth trace metal amalgam are transferred to an electrothermal vaporization device, the mercury is removed by evaporation, and the metals are then evaporated and determtned sknultaneously by ICP-AES. The method is applied to the determlnatlon of eight trace elements, Cd, Co, Cr, Cu, Mn, NI, Pb, and Zn, In water solution and In the biological standard reference rnaterlals urine and bovine liver. The method precision varled between 3.8 and 8.1%.
Of the 30 elements believed to be essential to the survival of living organisms, 12 are transition metals, including the three biologically active trace metals-Fe, Zn, and Cu. The remainder, i.e., Mn, Mo, Co, Cr, V, Ni, Cd, Sn, and Pb, are considered ultratrace since they involve less than 10 mg in the adult human (500 "C can give low recoveries for volatile elements, especially Cd and Pb; a lower ashing temperature,
