Stir bar sorptive extraction and liquid chromatography with UV detection for determination of antidepressants in plasma samples.

A sensitive and reproducible stir bar sorptive extraction and liquid chromatography (SBSE/LC-UV) method is described for the determination of sertraline, mirtazapine, fluoxetine, citalopram, paroxetine, imipramine, nortriptyline, amitriptyne, and desipramine in plasma samples. Important factors in the optimization of SBSE efficiency are discussed, such as extraction time, pH, ionic strength, influence of plasma proteins, and desorption conditions: solvents, modes (magnetic stir, ultrasonic), time, and number of desorption steps. The SBSE/LC-UV method showed to be linear in a concentration ranging from the limit of quantification (LOQ) to 1000.0 ng mL(-1). The LOQ values ranged from 10.0 ng mL(-1) to 40.0 ng mL(-1). The inter-day precision of the SBSE/LC-UV method presented coefficient of the variation lower than 15%. Based on figures of the merit results, the SBSE/LC-UV methodology showed to be adequate to the antidepressants analyses from therapeutic to toxic therapeutic levels. In order to evaluate the proposed method for clinical use, the SBSE/LC-UV method was applied to the analysis of plasma samples from elderly depressed patients.