A magnesium hydroxide coprecipitation technique for determination of Cd. Co, Cu, Mn, Ni in dialysis concentrate is described. The analytes are concentrated from 10 ml of dialysis concentrate into 1 ml of 1 M HNO3 and subsequently determined by graphite furnace atomic absorption spectrometry. Coprecipitation parameters and matrix effects are discussed. The precision, based on replicate analysis; is around 5% for the analytes, and recovery is quantitative, based on analysis of spiked samples and solutions including matrix components. (C) 1998 Elsevier Science B.V. All rights reserved.