2026-06-10T01:03:19+02:00 https://library.wur.nl/oai

oai:library.wur.nl:wurpubs/407617 2026-03-31

urn:nbn:nl:ui:32-407617 2026-03-31 urn:nbn:nl:ui:32-407617/mods Accurate determination of the Ca2+ activity in milk-based systems by Ca-ISE: Effects of ionic composition on the single Ca2+ activitiy coefficient and liquid junction potentials Gao R. 314606904 0000000391898292 aut van Leeuwen H.P. 314610138 0000000391627425 aut van Valenberg H.J.F. 314599827 0000-0002-7228-2073 0000000396887912 aut van Boekel M.A.J.S. 068436394 0000000116886561 aut text info:eu-repo/semantics/article 2011 10.1016/j.foodchem.2011.04.076 2-s2.0-79959963944 000293421400057 en Calcium ion selective electrode (Ca-ISE) was found to underestimate the actual Ca2+ ion activity in simulated milk ultrafiltrate (SMUF) and milk. It is shown that the ionic compositional difference between conventional calibration solutions and milk type samples had a significant effect on the single Ca2+ activity coefficient, which generates the erroneous estimate of Ca2+ activities in SMUF and milk. This study tests new standards with ionic profiles similar to SMUF, aiming at the reduction of the errors generated by the compositional difference between conventional standards and milk samples. As a result, the new standards showed a significant improvement in the accuracy of Ca2+ activity and Ca2+ activity coefficient over the conventional standards. The systematic error is reduced from 20% to 5% for SMUF and from 44% to 15% for milk. In addition, the new standards generate liquid junction potentials that are practically insignificant VLAG WIMEK Physical Chemistry and Colloid Science Product Design and Quality Management Group calcium-ion selective electrode ultrafiltrate VLAG WIMEK Laboratorium voor Fysische chemie en Kolloïdkunde Leerstoelgroep Productontwerpen en kwaliteitskunde Food Chemistry 129 2 619 623 03088146 urn:nbn:nl:ui:32-407617/obj 2026-03-31 http://purl.org/eprint/accessRights/RestrictedAccess