Application of planar chromatography to the determination of cotinine in urine of active and passive smoking pregnant women.

A quick and economical method for the determination of nicotine and its main metabolite-cotinine in urine from smoking and passively smoking pregnant women is proposed using TLC-densitometry. Chromatographic separations were performed on the plates coated with silica gel bound with C-18 alkyl chains. Chromatograms were developed using a mixture of acetonitrile and water (88 + 12, v/v) in a horizontal chamber. Visualization was carried out under UV illumination at lambda = 254 nm and then cotinine was quantified by the use of densitometer in reflectance mode at lambda = 260 nm. Nicotine was identified after derivatization with Dragendorff reagent under visible light. The results of nicotine and cotinine analysis were verified by questionnaires obtained from pregnant women according to their age and smoking status correlated with spontaneous abortion frequency and child death rate.