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@article{Saleesongsom:2027:10.1016/j.talanta.2026.130486,
author = {Saleesongsom, S and Plancherel, Y and Weiss, D},
doi = {10.1016/j.talanta.2026.130486},
journal = {Talanta},
title = {Optimising nonlinear calibration of glass pH electrodes over the pH range -4.5 to 15.5 using improved statistical treatment of acid and alkaline errors.},
url = {http://dx.doi.org/10.1016/j.talanta.2026.130486},
volume = {312},
year = {2027}
}
TY - JOUR
AB - Accurate calibration of the widely used glass pH electrode is particularly challenging at high (pH<1) and low (pH>11) proton activities (aH+), where the linear Nernstian relationship between the cell potential and log(aH+) breaks down. An asymmetric double-logistic function, selected from seven nonlinear function candidates by the corrected Akaike Information Criterion (AICc) and RMSE, best described the electromotive force (EMF)-pH relationship across both the acid- and alkaline-error regions from pH -4.5 to 15.5at 25°C(R2=1.00, RMSE=2.3mV). Reference pH was assigned from proton activity (Pitzer model, MacInnes convention) for five NIST/DIN buffers, ten H2SO4 standards (0.10-7.54molL-1H2SO4; pH -4.5 to 1) and nine NaOH standards (0.10-6.91molL-1 NaOH; pH 12.9 to 15.5). Relative to conventional three-point calibration, the function reduced acid-error bias by up to 3.0 pH units at pH -4.5 and alkaline-error bias by up to 1.5 pH units at pH 15.5. All-subsets and leave-one-out Monte Carlo analyses further showed that five acidic and three alkaline standards, with the NIST/DIN-traceable buffers, reproduced full-dataset accuracy to within ±0.25 pH unit at the extremes. This nonlinear calibration model enables continuous calibration over nearly twenty pH units; when only one region is of interest, the model reduces to a four-parameter logistic function. The reduced standard set retains accuracy while reducing calibration time by at least 50%.
AU - Saleesongsom,S
AU - Plancherel,Y
AU - Weiss,D
DO - 10.1016/j.talanta.2026.130486
PY - 2027///
TI - Optimising nonlinear calibration of glass pH electrodes over the pH range -4.5 to 15.5 using improved statistical treatment of acid and alkaline errors.
T2 - Talanta
UR - http://dx.doi.org/10.1016/j.talanta.2026.130486
UR - https://www.ncbi.nlm.nih.gov/pubmed/42715722
VL - 312
ER -
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