Spectrophotometric measurement of freshwater pH with purified meta-cresol purple and phenol red

Correction to Spectrophotometric Calibration of pH Electrodes in Seawater Using Purified m-Cresol Purple

This work examines the use of purified meta-cresol purple (mCP) for direct spectrophotometric calibration of glass pH electrodes in seawater. The procedures used in this investigation allow for simple, inexpensive electrode calibrations over salinities of 20-40 and temperatures of 278.15-308.15 K without preparation of synthetic Tris seawater buffers. The optimal pH range is ∼7.0-8.1. Spectroph...

Purification and Characterization of meta-Cresol Purple for Spectrophotometric Seawater pH Measurements

Spectrophotometric procedures allow rapid and precise measurements of the pH of natural waters. However, impurities in the acid-base indicators used in these analyses can significantly affect measurement accuracy. This work describes HPLC procedures for purifying one such indicator, meta-cresol purple (mCP), and reports mCP physical-chemical characteristics (thermodynamic equilibrium constants ...

The Use of Phenol Red and Brom-cresol Purple as Indicators in the Bacteriological Examination of Stools

1. Either phenol red or brom-cresol purple may be used as indicators in the preparation of lactose agar plates for the isolation of members of the typhoid-dysentery group of bacteria from stools. Of the two, brom-cresol purple gives sharper differentiation and is to be preferred. 2. These indicators exercise no restraining influence upon the growth of cultures of the typhoid bacillus or paratyp...

Phenol and Cresol

Degradation of phenol and p-cresol in reactors

The effects of hydraulic retention time (HRT) and phenol concentration on the degradation of phenol and p-cresol in wastewater were investigated in two respective UASB (upflow anaerobic sludge blanket) reactors with effluent recirculation at 37 oC for over 440 days. After acclimation, nearly all the phenol and p-cresol at moderate concentrations could be degraded without carbohydrate as a co-su...