A method for trace element determination of marine periphyton communities on discs of float glass (without sample preparation) using total-reflection X-ray fluorescence spectrometry

A quick method for trace element determination of marine periphyton communities on soda float glass discs is presented. After addition of an internal standard, the community is measured by total-reflection X-ray fluorescence (TXRF) spectrometry. No sample preparation is required except a gentle wash with distilled water. The soda glass disc on which the periphyton community grows is used directly as the sample reflector in TXRF. The method was evaluated by the analysis of a certified reference material of plankton (CRM 414) and by comparison to a wet digestion method. Recovery rates for 13 and 130 mu g-samples of CRM 414 are reasonable: between 0.6 and 1.4 for the elements K, Ca, Mn, Fe, Ni, Cu, Zn, As, Rb and Sr. Relative standard deviations for 130 mu g-samples are 10% or less for most of these elements. In the comparison to wet digestion, natural periphyton samples were used and the two methods showed a good agreement. The different steps used in the quantification, such as accounting for the contribution from the glass to the TXRF spectrum, and the calculation of the sample mass from the spectrum, are described. It is shown that complicating factors, such as the required water wash and the influence of an inhomogeneous spatial distribution of the periphyton on the glass disc, do not adversely affect the quantification. (C) 1998 Elsevier Science B.V.