Systematic Errors in the Determination of Trace Metals,Part II. Memory Effects of Quartz Vessels Used for Sample Preparation in the Determination of Ultra-Trace Levels of Platinum

The influence of different cleaning procedures applied to quartz vessels used for sample preparation on the Pt contents in blank solutions was studied. The platinum concentration was determined by inductively coupled plasma mass spectrometry. The strong dependence of the memory effect of the quartz crucible on the previously stored Pt content of the sample was observed. It was shown that cleaning a quartz crucible previously used for Pt determinations with hot nitric acid was insufficient. When heating the vessels with a mixture of nitric, perchloric and hydrochloric acid, considerable amounts of Pt are released. In the case of new crucibles, the platinum contents in blanks were very low after cleaning with hot nitric acid.