A SEQUENTIAL AND SIMPLE DETERMINATION OF ZINC, COPPER AND ALUMINUM IN BLOOD-SAMPLES BY INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

A sequential method of measuring zinc, copper and aluminium in serum by inductively coupled plasma (ICP) spectrometry is described. It involves a 1/5 dilution of serum with a potassium chloride solution which enhances aluminium signal intensity and reduces variations between different matrix compositions. The method is as sensitive as atomic absorption for zinc (sensitivity: 0.11-mu-mol/l) and copper (sensitivity: 0.020-mu-mol/l) and can also be applied to monitor aluminium (sensitivity: 0.12-mu-mol/l) for patients receiving total nutrition therapy or hemodialysis. Its linearity extends at least to 200-mu-mol/l for copper and zinc and to 20-mu-mol/l for aluminium. The correlations with atomic absorption are satisfactory for the 3 parameters, as assessed by the correlation coefficients established for both methods. A reference interval was established with 34 sera of control subjects (19 men, 15 women) which showed an average zinc, copper and aluminium of 14.5 (S.D. 2.6), 17.3 (S.D. 2.1) and 0.32 (S.D. 0.12) mu-mol/l, respectively. This method does not require a simultaneous ICP spectrometer and can be performed with 1 ml of serum in a single tube, using a routine sequential ICP spectrometer.