Reliability of the ICP-AES for trace elements studies of biological materials

In order to investigate the reliability of the Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) for trace element analysis of biological materials, we have carried out extensive investigations on human plasma, using an Applied Research Laboratory's ICP-AES. When we aspirated the untreated plasma into the spectrometer, we obtained unreliable and nonreproducible results. However, when we pretreated the plasma by wet digestion (to destroy all the organic material), we achieved reproducible and consistent results. It is, therefore, suggested that biological samples should be pretreated, preferably by wet digestion, before being aspirated into the ICP-AES for analysis.