Losses of Ag from solution by adsorption on to borosilicate glass and polyethylene sample containers are reported. In distilled water over 80% of a 1μgAgl^-1 solution may be adsorbed within 11 days. Acidification to 0.3 M HNO₃ satisfactorily preserved samples for this length of time and allowed direct analysis of Ag by graphite furnace atomic absorption spectrometry or pre-concentration by solvent extraction. Filtration through 0.45 μm membranes may bias the dissolved versus suspended partitioning of Ag in freshwaters in favour of the latter, by adsorption of soluble Ag.