Enantioanalysis of L-Histidine Using Enantioselective, Potentiometric Membrane Electrodes Based on Maltodextrins

Abstract

Three enantioselective, potentiometric electrodes (EPMEs) based on maltodextrins with different values of dextrose equivalent (DE) (maltodextrin I: DE 4.0–7.0; maltodextrin II: DE 13–17; maltodextrin III DE 16.5–19.5) were proposed for the assay of L-histidine in histidine raw materials and from its pharmaceutical formulation. The slopes of the electrodes were 58.3, 58.9, and 58.5 mV/decade of concentration for maltodextrin I, II, and III-based electrodes, respectively, and the detection limits were 1.97 × 10−12 mol/L, 1.72 × 10−12 mol/L, and 1.4 × 10−11 mol/L, respectively. All the electrodes are enantioselective and selective over polyvinylpyrrolidone, creatine, and creatinine. The L-histidine can be determined in the presence of D-histidine with recovery values higher than 99.10%. The proposed electrodes were successfully used for uniformity content tests of L-histidine in food supplements; the average recovery was higher than 97.30%. The surfaces of the electrodes were stable and easily renewable by simply polishing the alumina paper.