Capillary Electromigration Techniques for the Quantitative Analysis of Colchicine

The separation and UV absorbance detection of colchicine by three different capillary electrophoretic methods is described. Colchicine is known as a neutral compound, being able to be determined by electrokinetic chromatography. For the first time, a non-aqueous capillary electrophoretic method is described, based on the electromigration of ionized colchicine induced by 10 mM HClO4 in a mixture of methanol:acetonitrile (1:2, v/v) containing 60 mM ammonium formiate, opening up new perspectives in the trace analysis of the highly toxic drug from clinical and food samples using online coupling of the CE system to a mass spectrometer. For the quantitative assessment of colchicine content from meadow saffron (Colchicum autumnale L.) seeds and 1 mg colchicine tablets, a simple, quick and sensitive micellar electrokinetic chromatographic method was developed and fully validated according to ICH guidelines in terms of selectivity, linearity, accuracy, intermediate precision and limits of detection and quantification (95.2 ng mL(-1)). In order to further improve the detection limits, allowing the analysis of trace levels of colchicine in biosamples and food products, an on-column preconcentration using sweeping-MEKC was investigated. Linearity of response was observed on 10-160 ng mL(-1) colchicine, with an estimated detection limit of around 3 ng mL(-1) colchicine. By further improving the affinity of the separation vector towards colchicine this limit could be further decreased. Preliminary application of the method for the detection of trace amounts of colchicine spiked in non-fat milk and human urine (10 ng mL(-1)) shows encouraging results. (doi: 10.5562/cca1765)