Determination of cyclamate by a cheap and simple spectrophotometric method

Abstract

In this work, a simple method based on anthocyanins degradation by nitrite ion was used to determine cyclamate in table-top sweeteners. The method was carried out in four steps: (1) cyclamate hydrolysis (hydrolysed cyclamate, HC); (2) reaction between HC and nitrous acid; (3) anthocyanins degradation by residual nitrous acid; and (4) Absorbance measurements at 515 nm. The anthocyanins degradation reaction was done at 20 and 60 °C with 3, 5, 7, 10, and 15 mgL⁻¹ HNO₂, and several reaction times were tested (15, 30, 45, 60, 90, and 120 min). Under the best conditions (60 °C, 10 mgL⁻¹HNO₂ and 45 min of reaction time) the calibration curve for cyclamate was linear in the range from 3.19 to 20 mgL⁻¹; the relative standard deviation was 0.62% (for n = 5) and the limit of detection (LOD) was 0.96 mgL⁻¹. The method was applied for determination of cyclamate in table-top sweeteners and the results were compared with the official method (AOAC 957.09). The effect of synergistic sweeteners (aspartame, acesulfame, sucralose, and saccharin) was also analysed. The results show that the proposed method: (1) reduces considerably the analysis time (from 26 to 2 h, approximately); (2) decreases the LOD and the sample amount is lesser; (3) uses less number of reagents which produces few residues; and (4) it is friendly with the environment, because the anthocyanins source is a plant and the residues can be considered as non-toxics. According with the analysis of synergistic sweetener sacesulfame-K and sucralose present interference; meanwhile aspartame and saccharin (the most used with cyclamate) have not interference in the determination.