Affiliation:
1. Shanghai Maritime University
Abstract
An thin reagent containing optochemical film sensor for detecting and measuring free chlorine in water is described. The film sensor has been manufactured by immobilisation indicator of 3,5-dimethyl-4-hydroxybenzaldazine in a permeable transparent polymeric membrane. A linear calibration for free available chlorine can be obtained in the range between 0.05 and 3ppm. The limit of quantitation is 0.3 ppm, and the accuracy exceeds 7%. It takes about 150s to measure the relatively low occupational exposure concentration of 0.1ppm. The interference of combined chlorine has been studied. The sensor has no response to combined chlorine. And the stability of the sensors and the effect of external parameters like relative humidity (RH), temperature on the sensor response have been investigated. The sensor response is affected by varying the temperature; however, humidity in the range between 0 and 90% RH does not affect sensor response. The 3,5-dimethyl-4-hydroxybenzaldazine remained stable inside the polymeric film and no chemical reaction, crystallization or leaching occurred during 6 months of observation. Proper choice of indicator dye and polymeric material and successful application of kinetic evaluation method for the exposure experiments determine the desired features of the sensor.
Introduction
Publisher
Trans Tech Publications, Ltd.
Reference10 articles.
1. G.C. White, Handbook of Chlorination, Van Nostrand Reinhold, NewYork, (1986).
2. Standard Methods for the Examination of Water and Wastewater, 21st Edition, (2005).
3. J.B. Claver, M.C.V. Miron, L.F. Capitan-Vallvey, Analytica ChimicaActa 522 (2004), p.267.
4. M.G. Baron, R. Narayanaswamy, S.C. Thorpe, Sensors and Actuators B 29 (1995), p.358.
5. S.A. Momin, R. Narayanaswamy, Analyst 117 (1992), p.83.