Capillary gas chromatographic determination of Tamoxifen in the presence of a number of antidepressants in urine

A capillary gas chromatographic method with flame ionisation detection is described for the determination of Tamoxifen in association with the antidepressants Fluoxetine, Fluvoxamine, and Clomipramine, using Anastrozole as the internal standard. Optimal conditions were investigated: column head pressure (110 kPa), injector and detector temperature (230degreesC and 250degreesC, respectively), time and temperature of the splitless step (1.25 min and 80degreesC), injected volume (2 muL), and oven temperature programme. This provided analysis times of under 11 minutes. Good results were obtained for different aspects including stability of the solutions, linearity, accuracy, and precision. Detection limits between 2.4 and 12 mug L-1 were obtained for all the studied compounds. A ruggedness test of the method was carried out using the Plackett-Burman fractional factorial model with a matrix of fifteen experiments. The method which has been developed is easy, rapid and sensitive and has been used to determine Tamoxifen, Fluoxetine, Fluvoxamine, and Clomipramine present at clinically relevant levels in urine. Before GC-FID determination, it was necessary to apply a simple extraction preconcentration step to the urine using a C-18 cartridge with methanol as eluent.