Use of post-column ion-pair extraction with absorbance detection for the liquid chromatographic determination of cyclamate and other artificial sweeteners in diet beverages

Abstract

A simple post-column ion-pair extraction system was constructed from commercially available tees and tubing (made of chemically inert polymeric materials) and evaluated for the liquid chromatographic (LC) determination of cyclamate and related sweeteners. Ion-pair extraction was studied using several different dyes including methylene blue, methyl violet 2B and crystal violet with absorbance detection in the visible range (546 nm). Cyclamate (20 ng) produced a 1-cm peak (4% full scale) whereas the same response was obtained with 10 ng of either saccharin or acesulfam. The sweetener aspartame was not detected with the system. Other food additives, such as benzoate and sorbate, gave weak responses, whereas caffeine was not detected. Cyclamate was easily detected in spiked beverages by direct injection into the LC system.