Flow-through spectrophotometric sensor for the determination of saccharin in low-calorie products

Abstract

A simple, rapid and inexpensive monoparameter flow-through sensor has been developed for the determination of saccharin in low calorie and dietary products. The method is based on the transient adsorption of the sweetener on Sephadex G-25 solid phase packed to a height of 20 mm in the flow cell. The optimal transient retention of the synthetic sweetener, in terms of sensitivity and sampling frequency, was obtained when pH 2.75 citric acid-sodium citrate buffer 5 × 10⁻³ M was used as a carrier at a flow-rate of 1.5 ml min⁻¹. Saccharin was determined measuring its intrinsic absorbance at 217 nm at its residence time. Calibration graphs for peak height and peak area were linear over the range 5.0–200.0 μg ml⁻¹, RSD 1.18%, and 1.0–200.0 μg ml⁻¹, RSD 0.78%, respectively. Saccharin was determined in several food samples measuring height or area peak, obtaining recoveries ranging between 98–104 and 99–102% for height and area peak, respectively. The procedure was validated for use in the determination of saccharin in low calorie and dietary products giving reproducible and accurate results.

Keywords:

• monoparameter sensor
• saccharin
• flow-through optical sensor
• low calorie products
• dietary products

Acknowledgements

The authors are grateful to the Ministerio de Educacion y Cultura, Dirección General de Enseñanza Superior (Spain) (Project No. REN2000-2904E), for financial support.