Amperometric sensor based on carbon nanotube, ionic liquid, and polyaspartic acid for ascorbic acid determination.

An amperometric sensor for ascorbic acid determination has been developed by modifying the surface of a glassy carbon electrode (GCE) with polyaspartic acid (PolyAsp), carboxylated multi‐walled carbon nanotube (c‐MWCNT), and ionic liquid (IL, 1‐butyl‐3‐methylimidazolium hexafluorophosphate). The amount of each modification material on the surface was optimized in order to achieve good analytical performance. The operating conditions of c‐MWCNT−IL/PolyAsp/GCE were optimized. The performance characteristics of c‐MWCNT−IL/PolyAsp/GCE were investigated at optimum pH (8.0) and optimum potential (+0.20 V), and the sensor responded linearly to ascorbic acid between 5.3–2766.3 μM with a sensitivity of 19.64 μA mM−1 and detection limit of 3.0 μM. Determination of ascorbic acid in vitamin C tablet, vitamin C injection solution, and orange juice was successfully performed with the presented sensor and the recovery values were found between 98.9% and 101.6%. [ABSTRACT FROM AUTHOR]