Field-amplified sample stacking–sweeping of vitamins B determination in capillary electrophoresis

A capillary electrophoretic method for determination of five water soluble vitamins B along with baclofen as an internal standard has been developed and assessed in context of precision, accuracy, sensitivity, freedom from interference, linearity, detection and quantification limits. On-line preconcentration technique, namely field-amplified sample stacking (FASS)–sweeping, has been employed in respect to obtain more sensitive analysis. Separation conditions received after optimization procedure were as following background electrolyte (BGE), 10 mM NaH2PO4, 80 mM SDS, (pH 7.25); sample matrix (SM), 10 mM NaH2PO4 (pH 4.60); uncoated fused silica capillary (50 μm i.d. × 67 cm length); UV spectrophotometric detection at 200 nm; injection times: 10 s and 30 s at 3.45 kPa; applied voltage 22 kV; temperature 22 °C. Validation parameters, namely precision, accuracy and linearity, were considered as satisfactory. Under the optimized conditions, it has been also successfully applied for vitamins B determination in bacterial growth medium and commercially available Ilex paraguariensis leaves.

► Field-amplified sample stacking–sweeping method has been developed for vitamins B determination.
► Influence of injection time, SDS content, sample matrix pH value and ionic strength have been investigated and optimized.
► Theoretical aspects of elaborated method have been discussed.
► Capillary electrophoresis method has been successfully applied in bacterial growth medium and plant material analysis.