Accurate determination of the Ca2+ activity in milk-based systems by... (2011)

Titel 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
Gepubliceerd in Food Chemistry, Vol. 129, No. 2, p.619-623. ISSN 0308-8146.
Auteur Gao, R.; Leeuwen, van H.P.; Valenberg, van H.J.F.; Boekel, van M.A.J.S.
Datum 2011
Trefwoord(en) Laboratorium voor Fysische chemie en kolloïdkunde, Leerstoelgroep Productontwerpen en kwaliteitskunde, Physical Chemistry and Colloid Science, Product Design and Quality Management Group
Taal Engels
Type Artikel
Samenvatting 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
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Persistent Identifier urn:nbn:nl:ui:32-407617
Metadata XML
Repository Wageningen Universiteit & Researchcentrum

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