Abstract
A pH Test Strip was prepared from immobilized Tectona grandis leaf extract on alginate-chitosan membrane via entrapment technique. The changes in color and response time were observed in the pH range 2 to 8. The interaction of the membrane with the leaf extract was confirmed by an FTIR spectrophotometer by comparing the membrane spectra before and after entrapment. The pH test strip was tested on samples of food additive acetic acid. Color changes over the specified pH range were observed with a fast response time. FTIR analysis confirmed the interaction of chitosan of membrane with leaf extract. The test on real sample showed conformity with the test results using a universal pH indicator. Hence, the proposed pH test strip can be used as a good pH measuring indicator.