A novel pH optical sensor using methyl orange based on triacetylcellulose membranes as support

A novel pH optical sensor based on triacetylcellulose membrane as solid support was developed by using immobilization of methyl orange indicator. The prepared optical sensor was fixed into a flow cell for on-line pH monitoring. Variables affecting sensor performance, such as pH of dye bonding to triacetylcellulose membrane and dye concentration have been fully evaluated and optimized. The calibration curve showed good behavior and precision (RSD < 0.4%) in the pH range of 4.0-12.0. No significant variation was observed on sensor response with increasing the ionic strength in the range of 0.0-0.5 M of sodium chloride. Determination of pH by using the proposed optical sensor is on-line, quick, inexpensive, selective and sensitive in the pH range of 4.0-12.0. (C) 2014 Elsevier B.V. All rights reserved.