Use of β-cyclodextrin inclusion concurrent with cationic surfactant shielding for the enhancement of ascorbic acid stability followed by ultra-high performance liquid chromatography and online preconcentration capillary electrophoresis

摘要

In the current study, ?cyclodextrin (?CD) inclusion concurrent with cationic surfactant shielding was firstly evaluated for the successful stabilization of L-ascorbic acid (AA) under ambient lab conditions followed by ultra-high performance liquid chromatography (UHPLC) and online preconcentration capillary electrophoresis (CE). The combination of 0.44 mM ?CD with 10 mM cetyltrimethyl ammonium bromide (CTAB) cationic surfactant (?CD-CTAB) was significantly reduced the degradation of AA at pH 7.0 with 11 d stability. However, the combination of ?CD with sodium dodecyl sulfate (SDS) anionic surfactant (?CD-SDS) gave only 1 d stability of AA. Moreover, ?CD-CTAB complex was stabilized AA with 175- and 12-fold enhancement compared with individual ?CD and CTAB, respectively. The formation of AA-?CD-CTAB ternary complex was proved by following the chromatographic and electrophoretic behavior of AA in the absence and presence of ?CD and CTAB species. Thus, the obtained results were very promising and clearly provided a higher stability for AA without any molecular changes which normally limited the application of different analytical methods. After that, the reversed phase UHPLC/UV and CE/UV methods were developed for the quantitative determination of AA in different commercially available samples including pharmaceuticals, drinking juices and milk samples. Good linearity within the concentration range 11000 礸/mL was achieved with coefficient of determinations (r2) higher than 0.9995. The limits of detection were 0.39 and 0.56 礸/mL by UHPLC and CE, respectively. The proposed methods could be suitable for the quality control of AA, providing simple, rapid and reliable approaches for routine analysis of different pharmaceuticals and food.