Spacer-Enhanced Resolution of Thiamine and Pyridoxine in Hydrodynamically Closed Two-Dimensional Capillary Isotachophoresis Coupled With Tandem Mass Spectrometry.

The effect of specific spacers added to the separation environment of capillary isotachophoresis in a hydrodynamically closed two-dimensional device hyphenated with tandem mass spectrometry is reported in this short communication. Combination of two spacers, here, 2-amino-2-hydroxymethyl-propane-1,3-diol and histidine, led to enhanced resolution of two model analytes (thiamine and pyridoxine) in model and real pharmaceutical samples (tablet drug dosage form). The addition of the spacers at relatively high concentration level (i.e., 20 µg/mL) caused no significant interference and suppression of the analytical signal in the mass spectrometry detection step. Eco-friendliness, practicality, and performance of the method were confirmed using the metric tools of the "White Analytical Chemistry." High repeatability of the separation process could broaden the application possibilities of the hydrodynamically closed capillary electrophoresis system.