Microchim Acta 151, 109–113 (2005) DOI 10.1007/s00604-005-0389-5 Original Paper Potentiometric Membrane Sensor for Determination of Saccharin Mohamed A. F. Elmosallamy 1; , Mohamed M. Ghoneim 2 , Hamada M. A. Killa 1 , and Amr L. Saber 1 1 Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt 2 Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt Received April 19, 2004; accepted May 16, 2004; published online August 19, 2005 # Springer-Verlag 2005 Abstract. A potentiometric poly(vinyl chloride) mem- brane sensor for determination of saccharin is described. It is based on the use of Aliquat 336S-saccharinate ion-pair as an electroactive material in plasticized PVC membranes with o-nitrophenyloctylether or dioctyl- phthalate. The sensor is conditioned for at least two days in 0.1 mol L 1 sodium saccharinate before use. It exhibits fast, stable and Nernstian response for sac- charinate ions over the concentration range of 1.0  10 1 –5.0  10 5 mol L 1 and pH range of 4.5–11. The sensor is used for determination of saccharin in some dosage forms. Results with an average recovery of 101% and a mean standard deviation of 0.2% are obtained which is compared favourably with data ob- tained using the British pharmacopoeia method. The sensor shows reasonable selectivity towards saccharin in presence of many anions and natural sweeteners. Key words: Aliquat 336S-saccharinate ion-pair; PVC membrane; potentiometry; saccharin determination. Saccharin is a known synthetic intense sweetener, pro- duced commercially as an artificial sweetener in acid form and as sodium or potassium salt. It is approxi- mately 300 times sweeter than sucrose. Saccharin is widely used alone or in combination with aspartame in all types of foods (soft drinks, processed foods, cosmetics, tooth pastes, desserts, mixes, drugs, and many other commercial products) and currently ap- proved in more than 90 countries [1, 2]. Saccharin is not metabolized by humans, it is rapidly excreted unchanged in the urine and does not accumulate in body tissues. Therefore, it is a true nonnutritive sweetener [3], so it is useful for diabetic individuals and obesity [4]. It also reduces the incidence of dental caries [5]. On the other hand, there are several methods in the literature for the determination of saccharin and its salts. These include high performance liquid chroma- tography [6–12], gas chromatography [13–15], thin layer chromatography [16–18], paper chromatography [19], spectrophotometry [20–23], infra-red spectrome- try [24, 25], voltammetry [26–29], potentiometry [30] and ion-selective electrodes [31–34]. Previous work confirms the suitability of Aliquat 336S as a counter ion for preparation of membrane sensors responsive to chloranilate and urate ions [35, 36]. This paper describes a potentiometric membrane sensor responsive to saccharin. The sensor is based on the use of Aliquat 336S – saccharinate ion-pair as an electroactive material dispersed in plasticized poly (vinyl chloride) (PVC) using either o-nitrophe- nyloctyl ether or dioctylphthalate. The sensor reveals sensitive and selective response over a wide range of succharin ion concentrations and pH values.  Author for correspondence. E-mail: melmosallamy@ yahoo.com