A green chemistry approach using Alternanthera brasiliana extract for urea biosensor.

A biosensor is an analytical method that uses an active biological component that is integrated with electronic equipment to determine the analyte concentration. One of the biosensor methods widely developed is colorimetric-based detection. The purpose of this research was to study the potential of the use of purple spinach (Alternanthera brasiliana) leaf extract as a urea biosensor indicator. The research was performed including the leaf extraction, characterization, and application as a urea biosensor indicator. The results showed that the optimum purple spinach leaf extraction using Ethanol-HCl 85:15 (v/v) with an absorbance of 0.802 at a maximum wavelength of 531 nm. Furthermore, the leaf extract showed high stability in acid, low temperature (<4^oC) storage, and the addition of reducing agent. The purple spinach leaf as an indicator of urea biosensor showed a linear correlation between the color change and urea concentration, with the regression line of y=-0.0007x+0.6397 and R2 of 0.961. [ABSTRACT FROM AUTHOR]