Biamperometric titration and flow injection determination of cyclamate in low-calorie products

Abstract

Titration and flow injection (FI) methods with biamperometric detection at 0.7 V are proposed for determining cyclamate and are tested for various diet products. The titrant–reagent system was sodium nitrite in 1.0 mol l^–1 phosphoric acid and there was no interference from glucose, fructose, sucrose, lactose, sorbitol, saccharin, benzoic acid, salicylic acid, fumaric acid, Sunset Yellow and Bordeaux-S. For the biamperometric titration method, the detection limit was 1.3 × 10^–3 mol l^–1 and the relative standard deviation (s_r) was 1.0% for a solution containing 5.0 × 10^–3 mol l^–1 cyclamate (n= 9). The recovery of the sweetener from four low-calorie products ranged from 97.6 to 102.5% of the labelled amount. For the FI method there was a direct relation between cyclamate concentration and current decrease over 5.0 × 10^–3 to 4.0 × 10^–2 mol l^–1 cyclamate with a detection limit of 2.5 × 10^–3 mol l^–1 and an s_r of 1.7% for a solution containing 2.5 × 10^–2 mol l^–1 cyclamate (n= 10). Ninety results can be obtained per hour, and these, for various low-calorie products, are in good agreement with those obtained by a spectrophotometric FI method (r= 0.9993) and/or the labelled amount (r= 0.9937).