Buffer Standards for Physiological pH of the Buffer N-(2-Acetamido)-2-aminoethanesulfonic Acid from 5°C to 55°C

Blake M. Bodendorfer, Zachary M. Downs, Isaac B. Henson, Lakshmi N. Roy, Rabindra N. Roy, Jessica M. Stegner, Jaime A. Veliz, Joshua T. Wollen

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DOI: 10.4236/ojpc.2011.13016                

Abstract

Electromotive force (emf) measurements of the Cell Pt(s), H₂(g)|ACES(m₁) + NaACES(m₂) + NaCl (m₃)| AgCl, Ag(s) have been carried out from 5°C to 55°C . The agreement of pH values between two calculated (extended Debye-Hückel and liquid junction correction) is very good. Two buffer solutions without the chloride ion and seven buffer solutions with NaCl, at an ionic strength (I = 0.16 mol.kg^-1) similar to that of physiological fluids, have been studied. The pH values for these buffer solutions have been evaluated in the temperature range of 5°C to 55°C using the extended Debye-Hückel equation of the Bates-Guggenheim convention. Values of the residual liquid junction potential (δE_j) between the ACES solutions and the saturated KCl calomel electrode solution have been estimated at 25°C and 37°C from the previously determined E_j values using the flowing junction cell to determine the operational pH values at 25°C and 37°C. These ACES buffer solutions are recommended as secondary standard reference solutions for pH measurements in the range of physiological applicati on at I = 0.16 mol.kg^-1.

Keywords

Buffer, Emf, pH, Zwitterionic

Conflicts of Interest

The authors declare no conflicts of interest.

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