Comparison of slurry preparation and microwave digestion of freshwater algae for multi-element analysis by total reflection X-ray fluorescence spectrometry

Abstract

The purpose of this study was to investigate the usefulness of slurry sampling for total reflection X-ray fluorescence (TXRF) analysis of freshwater algae. Slurry samples were prepared from freeze-dried algae by sonication. Solution samples were prepared by vapour-phase microwave digestion. TXRF analyses of 20-200 µg of specimens made from freeze-dried algal samples are reported. The concentrations of P, K, Ca, Mn, Fe, Cu, Zn and Pb were determined in the range 5-40 000 µg g ^–1 ; similar values have been published by other investigations for marine and freshwater algae samples. Good agreement was found between the results of the TXRF analysis of the slurries and the digested samples, and also the results of an additional inductively coupled plasma atomic emission spectrometric analysis of the digested samples. Student's t-test was used to demonstrate the applicability of slurry sampling. It is concluded that the slurry preparation simplifies the sample treatment and is suitable for TXRF measurement.