Potentiometric sensor for sorbic acid determination in food products

• Published in: Food chemistry Vol. 115; no. 4; pp. 1563 - 1567
• Main Authors: Santini, Alberto O., Pezza, Helena R., Carloni-Filho, João, Sequinel, Rodrigo, Pezza, Leonardo
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.08.2009; [Amsterdam]: Elsevier Science; Elsevier
• Subjects: analytical methods; Biological and medical sciences; detection; electrodes; food analysis; food composition; Food industries; food preservatives; Fundamental and applied biological sciences. Psychology; Jams; Milk and cheese industries. Ice creams; Non alcoholic beverage industries and mineral waters; potentiometric sensor; Potentiometry; rapid methods; Sauces; sensors; Skim yogurts; Soft drinks; Sorbate-sensitive electrode; sorbic acid; Sorbate-sensitive electrode; Potentiometry; Skim yogurts; Sauces; Jams; Soft drinks; Dairy product; Yogurt; Electrodes; Sauce; Jam; Soft drink; Food
• DOI: 10.1016/j.foodchem.2009.02.012
• ISSN: 0308-8146

The construction, evaluation and application of a new potentiometric sensor, namely, Pt|Hg|Hg 2(SOB) 2 |Graphite, where SOB stands for sorbate ion, are described. This electrode has a wide linear dynamic range between 5.0 × 10 −7 and 1.0 × 10 −2 mol L −1 with a near-Nernstian slope of (−58.6 ± 1.3) mV decade −1 and a detection limit of 4.3 × 10 −7 mol L −1. The potentiometric response is independent of the pH of the solution in the pH range 6.0–9.0. The electrode is easily constructed at a relatively low-cost with fast response time (within 15–30 s) and can be used for a period of 4 months without significant change in its performance characteristics. The proposed sensor displayed good selectivities over a variety of other anions (carboxylates and inorganic anions). The potentiometric sensor was successfully applied to the determination of sorbic acid in real food samples, that is, soft drinks, skim yogurts, jams and sauces.