Rapid simultaneous determination of four indole compounds in dietary supplements by micellar electrokinetic chromatography with a dilute and shoot step

Abstract

© 2016 The Royal Society of Chemistry. A simple micellar electrokinetic chromatography (MEKC) method with UV detection was developed for the simultaneous determination of indole-3-carbinol, indole-3-acetonitrile, indole-3-acetic acid and 3,3′-diindolylmethane. These compounds are potentially used in cancer prevention. Investigation of solvent effects (methanol and dimethylformamide) on MEKC analysis was carried out. A dilute and shoot strategy was used for sample preparation to reduce the time required for multiple steps such as solvent evaporation. The final conditions were electrokinetic injection for 3.0 s at 423 V cm-1and 20.0 mM borate buffer (pH 9.00) containing 20.0 mM SDS. Analysis was rapid, achieved in less than 4.5 min. Linear calibration curves for the indole compounds in the range 5-200 μg mL-1(r2> 0.999) were obtained. Intra- and inter-day precisions were 2.0-7.9% RSD, with LOQs in the range of 1.5-4.0 μg mL-1and recoveries in the range of 90-110% (n = 5).