Optical ph sensing material prepared from doped sol-gel film for use in acid-base titration

Musa Ahmad (School of Chemical Science and Food Technology Faculty of Science and Technology Universiti Kebangsaan Malaysia)
T.W. Tan (School of Chemical Science and Food Technology Faculty of Science and Technology Universiti Kebangsaan Malaysia)

ASEAN Journal on Science and Technology for Development
Vol. 18 No. 2 (2001): ASEAN Journal on Science and Technology for Development (AJSTD)

An optical pH sensing material has been prepared in this study by using sol-gel technique. Bromothymol blue, bromophenol blue and thymol blue were chosen in this study as acidbase indicators for strong acid-strong base, strong acid-weak base and weak acid-strong base titration, respectively. The results show that these indicators could be successfully entrapped inside the sol-gel film and still maintain its chemical behaviour as in solution. The entrapped acid-base indicators respond well to any pH changes and could be used to determine the end-point of the acid-base titration.