Article ID Journal Published Year Pages File Type
1247337 Talanta 2006 5 Pages PDF
Abstract

The preservation of arsenic species in water samples is an indispensable method to avoid their changes during storage, if it is not possible to analyse them immediately. The aim of this investigation was to demonstrate the limitations of the suggested method by using phosphoric acid as a preservation agent. The samples remain stable for 3 months, even if they show evidence of high concentrations of iron or manganese. Critical is an increasing pH > 3. Theoretically, a precipitation of strengite (Fe3(PO4)2) could occur, which should be avoided. Phosphoric acid with a final concentration of 10 mM is recommended as a preservation agent, combined with keeping the samples cool (6 °C) and dark. Filtration of samples before preservation may be carried out with respect to the analytical aim to distinguish between the total and soluble fraction (without colloids). It was shown that filtered and non-filtered samples can be preserved by utilising the above mentioned scheme.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
Authors
, , , ,