Construction of optical pH sensor as a new platform optical urea biosensor based on
polyelectrolyte complex (PEC) pectin-chitosan membrane and total phenolic (anthocyanin)
of Tapak Dara flower (Catharanthus roseus) has been successfully carried out. The
anthocyanin was extracted by a maceration method for 72 hours using methanol, and a total
extract yield was 21.56% or 1.803 mg/L. Flavonoid and phenol tests showed positive results
indicated by the formation of red and black colours. The anthocyanins showed maximum …