Simultaneous Determination of Nicotine and Cotinine in Untreated Human Urine by Micellar Liquid Chromatography

A simple, precise, accurate and sensitive method for the simultaneous determination of nicotine and cotinine by direct injection of human urine was developed and validated. This method utilizes nontoxic, nonflammable and relatively inexpensive sodium dodecylsulphate (SDS) as a mobile phase and eliminates the need for pretreating the urine. Optimum conditions for the separation of cotinine and nicotine, the column efficiency, and the elution of nonalkaloid components in urine were investigated. Nicotine and cotinine in untreated human urine were separated and quantitatively eluted using 0.20 M SDS and 3% 2-propanol at a pH of 4.60 and column temperature at 40 °C. Retention times for nicotine and cotinine were: 10.85 and 9.48 minutes respectively, and all components in the urine sample were eluted within 15 minutes. This method may be suitable for use in hospitals, research centers, or in a physician's office.