• Posted on: Fri, 10/07/2016 - 15:52
  • By: jackie
Spectrophotometric measurement of freshwater pH with purified meta-cresol purple and phenol red
Lai, C.Z., M.D. DeGrandpre, B.D. Wasser, T.A. Brandon, D.S. Clucas, E.J. Jaqueth, Z.D. Benson, C.M. Beatty, and R.S. Spaulding

Impurities in indicator salts can significantly bias spectrophotometric pH determinations. In this work, two purified sulfonephthalein indicators, meta-cresol purple (mCP) and phenol red (PR), were tested for analysis of freshwater pH on the free hydrogen ion concentration scale. The work presented here is the first parallel comparison with two purified indicators used to determine pH of the same freshwater samples.