Additional considerations for trace element analysis of environmental matrices using inductively coupled plasma atomic emission spectrometry with ultrasonic nebulization

This work compares efficiencies of pneumatic and ultrasonic nebulizers and discusses drawbacks observed in trace element analyses of environmental matrices using ICP-AES with ultrasonic nebulization. The interference observed is mainly due to variable calcium content in samples; in most cases the excessive plasma loading by Ca is responsible for signal suppression of analyte elements. Such matrix effect may be managed to a certain extent using a classical internal standardisation that is discussed in details. Under well defined conditions, the ICP-AES-USN analysis of most trace elements leads to accurate results for matrices usually studied. However, due to chemical reactions occurring in the condensation stage of the ultrasonic nebulizer and subsequent analyte losses to the waste, the ICP-AES-USN analysis of copper and particularly of boron has to be avoided because it leads unavoidably to erroneous results. This drawback cannot be resolved by usual means of correction but may be overcome by using conventional pneumatic nebulizers.