Flow-injection spectrophotometric determination of cyclamate in sweetener products with sodium 1,2-naphthoquinone-4 sulfonate

A method for the determination of cyclamate in sweetener tablets is propose d. The method is based on the conversion of cyclamate to cyclohexylamine an d the subsequent reaction with 1,2-naphthoquinone-4-sulfonate, yielding a s pectrophotometrically active derivative which is detected at 480 nm. The hy drolysis step is performed batch wise by treatment of cyclamate with hydrog en peroxide and hydrochloric acid, while the cyclohexylamine derivatization is carried out in a flow-injection system. Conditions for both hydrolysis and derivatization have been optimised. The Linear range is up to 10(-3) M cyclamate, the overall repeatability 3.1% and the detection limit is 7.7 x 10(-6) M. The accuracy of the method proposed in the analysis of commercial sweetener tablets is about 3.5%. (C) 1999 Elsevier Science B.V. All rights reserved.