New procedure for column-switching isotachophoretic determination of vitamins B1 and B6 in beer samples

Capillary isotachophoresis with conductivity detector working in a column-switching mode was applied for the determination of vitamins 81 and B6 in beer samples. Optimized ITP electrolyte system composed of 10 mM sodium acetate adjusted to pH = 5.0 with acetic acid and with 1% hydroxyethylcelulose as the leading electrolyte, and 10 mM aminocaproic acid (pH = 6.0) as the terminating electrolyte, was selected for analysis. The new composition of leading and terminating electrolytes has been used for the determination of vitamins B1 and B6 in.beer samples from the selected stages of the brewing process. The developed column-switching ITP procedure was characterized by linearity, detection and quantification limits, and precision (coefficient of variation was <2% for standard solution and <5% for beer samples). The average recoveries for the standard solutions of vitamins varied between 97.4-99.6%, whereas, for the standard addition method, were in the range 97.5-100.9% indicating satisfactory accuracy of the proposed electrolyte systems. (C) 2017 Elsevier Inc. All rights reserved.