A clean method for flow injection spectrophotometric determination of cyclamate in table sweeteners

A flow system based on the multicommutation is proposed for fast and clean determination of cyclamate. The procedure exploits the reaction of cyclamate with nitrite in acidic medium and the spectrophotometric determination of the excess of nitrite by iodometry. The flow system was designed with a set of solenoid micro-pumps to minimize reagent consumption and waste generation. The detection limit was estimated as 30 μmol L⁻¹ (99.7% confidence level) with linear response ranging up to 3.0 mmol L⁻¹. The coefficient of variation was estimated as 1.7% for a solution containing 2.0 mmol L⁻¹ cyclamate (n = 20). About 60 samples can be analyzed per hour, consuming only 3 mg KI and 1.3 μg NaNO₂, and generating 2.0 mL of effluent per determination, thus providing an environmentally friendly alternative to previously proposed procedures. Common artificial and natural sweeteners did not interfere when present in concentrations 10-times higher than cyclamate. The procedure was successfully applied for determination of cyclamate in artificial table sweeteners with results in agreement with the reference method at the 95% confidence level.