The Malaysian Journal of Analytical Sciences Vol 11 No 2 (2007): 351 – 360

 

 

POTENSI KURKUMIN SEBAGAI PENUNJUK pH SEMULAJADI UNTUK PEMBANGUNAN SENSOR OPTIK pH

 

Rosmawani Mohammad, Musa Ahmad & Jamaluddin Mohd Daud

 

Pusat Pengajian Sains Kimia & Teknologi Makanan, Fakulti Sains & Teknologi

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor

 

Abstract

The potential of curcumin reagent as a natural pH indicator for the development of an optical pH sensor was discussed in this study. Curcumin has been chosen because it has never been reported before for use in the development of an optical pH sensor. Curcumin is a colouring constituent  of tumeric that giving yellow  pigmentation.  Curcumin showed clear colour changes i.e. yellow in acidic and reddish-brown in basic solutions. The colour change is fast i.e. within 5 seconds. Results from the study showed that a linear pH range for this reagent was observed at pH 8-12 (R2  = 0.9854). Curcumin has a good photostability  with RSD value of 1.42%  for a study period of 6 months. The RSD values of the reproducibility study were found to be 1.43% and 0.37% for pH 9 and pH 12, respectively. Characterisation of the immobilised curcumin reagent also showed promising results, hence a good potential for use as a sensing reagent for an optical pH sensor.

 

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