Methods of Elimination of Hafnium Interference in the Determination of Platinum in Environmental Samples by ICP-MS Technique

The widespread use of autocatalysts containing platinum as one of active components generates an ecological awareness on the introduction of the metal into the environment. The evaluation of the level of the metal emission and a risk to living organisms from catalyst technology requires the examination of a large variety of environmental samples for the content of ultra-traces (pg g(-1) and ng g(-1)) of platinum. Inductively coupled plasma-mass spectrometry is the most promising instrumental technique for the detection of low concentrations of the elements in complex matrices. The application of the technique to the detection of platinum in environmental materials is seriously hampered by hafnium which can occur in such samples. The ICP-MS signals of platinum isotopes are overlapped by the signals of HfO+ ions generated under plasma conditions. Methods developed for the elimination of the effect of hafnium on the detection of platinum by ICP-MS technique are presented in the paper. Possibilities and limitations of mathematical correction; modifications in sample introduction techniques; the use of dynamic reaction cells, double-focusing sector field mass spectrometers and chemical separation procedures are discussed in detail.