Apparent binding of ionized calcium by various buffers.

Abstract:

:Using different substance concentrations in an aqueous 1.25 mmol/L solution of CaCl2 plus NaCl to a final solution ionic strength of 160 mmol/L, we tested six buffers for their effect on measurements of ionized calcium (Ca2+). Measured Ca2+ decreased with increasing ionic strength and pH. Increasing concentrations of Tris caused a positive Ca2+ electrode bias; the other five buffers caused a negative Ca2+ electrode bias with increasing concentration. 4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid ("HEPES") at 10 mmol/L maintained pH 7.39 in the aqueous reference solutions containing 0.75 to 2.50 mmol of CaCl2 per liter, and showed a linear Ca2+ response among three different suppliers of Ca2+ instruments; it is thus a suitable buffer for a reference solution.

journal_name

Clin Chem

journal_title

Clinical chemistry

authors

Crowell JA,Bowers GN Jr

subject

Has Abstract

pub_date

1985-02-01 00:00:00

pages

267-70

issue

2

eissn

0009-9147

issn

1530-8561

journal_volume

31

pub_type

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