Green Flow Injection Spectrophotometry with Betel Nut (areca Catechu L.) Natural Reagent for Indirect Determination of Ascorbic Acid

A green flow injection spectrophotometric technique for the determination of ascorbic acid was described based on the redox and complexation reactions. Iron(III) was reduced to iron(II) by ascorbic acid with subsequent complexation reaction of remaining iron(III) with a natural reagent extracted from Areca catechu L. at pH 5.0 yielding a dark-blue color. Absorbance decreased with increasing ascorbic acid concentration. A linear range of 1–10 mg/L for ascorbic acid was obtained with r2 of 0.9986. Limit of detection and limit of quantification were 0.3 and 0.9 mg/L, respectively. Relative standard deviation was less than 5.0%. This method was utilized to quantify ascorbic acid in pharmaceuticals and soft drinks with a sampling rate of 40 h−1. Ascorbic acid contents of 96–100% in pharmaceutical samples were obtained, while recoveries for spiked ascorbic acid standard at 3 mg/L in soft drinks were 92–113%.