Sample diluent for measurement with ion-selective electrodes and method of using the same

摘要

A body fluid sample is diluted with a diluent which comprises an aqueous solution containing bis(2-hydroxyethyl)-iminotris(hydroxymethyl)methane and boric acid to obtain a diluted body fluid sample, and the ion concentration in the diluted body fluid sample is determined with ion-selective electrodes, whereby the variation width of pH in the diluted body fluid sample can be held down to a narrow range; resultingly, the determination can be made without exerting adverse effects on the ion-selective electrodes and errors in determination can be markedly reduced as compared with cases where the conventional diluents are used.