Numerical Computation of pH and Buffer Capacity in Complex Mixtures of Acids, Bases and Ampholytes

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DOI: https://doi.org/10.14456/sustj.2012.6
Keywords:
pH buffer capacity computational prediction algorithm

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Wibul Wongpoowarak
Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Thailand.
Damrongsak Faroongsarng
Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Thailand.
Nimit Worakul
Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Thailand.
Prapaporn Boonme
Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Thailand. Corresponding author's e-mail: prapaporn.b@psu.ac.th

Abstract

This study was aimed to simplify the pH calculation for complex mixtures of acids, bases andampholytes; the theoretical concept on pH calculation was renovated. A new algorithm was proposed tostate that buffer capacity (b) could be simultaneously achieved with pH. To validate the method, the buffersystems of Na2HPO4/NaH2PO4 and Na2HPO4/citric acid were employed. Acid and base titration was doneon the buffer systems using HCl and NaOH, respectively. It was demonstrated that only the charge balanceequation (CBE) was necessary and sufficient to successfully compute b. To achieve the desirable accuracy,the pH interval used in such algorithm should be 10-4 for general calculation; between 10-4 and 10-2 for 8significant-digits calculation; between 2 x 10-10 and 4 x 10-4 for 16 significant-digits calculation. Visual BasicSource Code written in Microsoft AccessTM for demonstrating computation of pH and b of pure water was also illustrated.

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How to Cite
Wongpoowarak, W., Faroongsarng, D., Worakul, N., & Boonme, P. (2013). Numerical Computation of pH and Buffer Capacity in Complex Mixtures of Acids, Bases and Ampholytes. Science, Engineering and Health Studies, 6(2), 20–29. https://doi.org/10.14456/sustj.2012.6
Issue
Volume 6, Number 2 (July - December), 2012
Section
Research Articles

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