Analytical Sciences


Abstract − Analytical Sciences, 35(3), 347 (2019).

Towards Green Titration: Batchwise Titration with Reusable Solid Sorbed Indicators
Miki KANNA,* Sarawut SOMNAM,* Wasin WONGWILAI,**,*** and Kate GRUDPAN*,**,***
*Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
**Center of Excellence for Innovation in Analytical Science and Technology, Chiang Mai University, Chiang Mai, 50200, Thailand
***Science and Technology Research Institute, Chiang Mai University, Chiang Mai, 50200, Thailand
We propose the creation of reusable indicator-sorbed-solids, using anion-exchange resins or kaolin as supports, with the aim to reduce chemical use towards green analytical chemistry. Indicators (phenolphthalein, thymol blue and butterfly pea flower extract as a natural indicator) sorbed on a solid support, were employed in acid-base titration, in both homogenous aqueous and heterogenous aqueous organic phases. Applications of the developed techniques to some real samples, such as vinegar, colored fruit juice and vegetable oil, have been demonstrated.