ANTIOXIDANT CAPACITY ASSAYS OF SELECTED THAI HERBS BY LOW COST SEQUENTIAL INJECTION ANALYSIS WITH ELECTROCHEMICAL DETECTION
Rapid methods for screening of antioxidant capacity in biological samples and monitoring of natural antioxidants and derivatives in processed products are in high demands. The online analytical technique, sequential injection analysis (SIA) with electrochemical detection (ECD) was developed and applied to 2,2-azino-bis(3- ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay and the reagentless electrochemical index (EI) assay. The cathodic current signal of the remaining ABTS radical was monitored after the reaction with antioxidant or the oxidation current signal of antioxidant was directly detected in a low cost, laboratory made, acrylic flow-through detector cell using the same SIA-ECD system. The Masterflex peristaltic pump of SIA-ECD system was semi-automatically controlled by the in house pump drive software written in Processing language. Total antioxidant capacity of selected Thai herbs infusions determined with SIA-ECD provided sample throughputs of 20 and 32 samples h-1 by the ABTS assay and EI assay, respectively. The results reported in gallic acid equivalent unit were in good agreement with classical spectrophotometric ABTS assay.
Chaisuksant, R., Boonto , N., Meanha, P., Hongwitayakorn , A. and Kongkedsuk, J. (2015). ANTIOXIDANT CAPACITY ASSAYS OF SELECTED THAI HERBS BY LOW COST SEQUENTIAL INJECTION ANALYSIS WITH ELECTROCHEMICAL DETECTION. Acta Hortic. 1088, 521-526
ABTS assay, antioxidant capacity, electrochemical index, herbs, low cost SIAECD, gallic acid equivalent