Ali Asghar Amiri - Faculty of Science, Department of Chemistry, - Islaic Azad University of Firozabad branch
Azadeh Azadian - Islaic Azad University Firouzabad branch

In this study, based on the characteristics of the optical sensor to determine the pH was afraid of 2,3-dihydro-3- oxoindolyliden or indigo identifier described on membrane tool to evaluate and measure the pH in the range 2.5 to 6 respectively.Apted response time of 6 minutes and a good selection of the ion. The optical sensor with 0.1 M sodium hydroxide solution over time is a few seconds to be revived. The sensor for measuring pH on natural samples (Tequila) were tested and it was found that the accuracy is good.If maintaining stability and sustainability membrane in distilled water is very good. The membrane can be used to detect acidic environment in the lab and determine the pH in different laboratories, such as food, pharmaceutical and medical applications.

Optical sensor, 2,3-dihydro-3- oxoindolyliden, Ethylene diamine, PVC