Combination of corona discharge ion mobility spectrometry with a novel reagent gas and two immiscible organic solvent liquid–liquid–liquid microextraction for analysis of clomipramine in biological samples

A novel and sensitive method based on combination of two immiscible organic solvents hollow fiber-based liquid–liquid–liquid microextraction and corona discharge ion mobility spectrometry (HF-LLLME–CD-IMS) was employed for the analysis of clomipramine in human urine and plasma. The effect of formic, acetic and propionic acid as the reagent gas (dopant) on the corona discharge ion mobility signal was investigated. The influence of dopant amount was also studied. Optimum mass flow rates of the dopants were 3.7, 1.1 and 1.0 μmol min−1 for formic, acetic and propionic acid, respectively. Experimental parameters influencing the extraction efficiency of HF-LLLME, such as NaOH concentration as donor solution, ionic strength of the sample, stirring rate, and extraction time were investigated and optimized. Under the optimum conditions, analytical parameters such as linearity, precision and limit of detection were also evaluated. The linear dynamic range was from 1 to 100 μg L−1 (r2 = 0.9980) and the limit of detection was 0.35 μg L−1. Intra- and inter-day precisions were satisfactory with a relative standard deviation (RSD) of 5.9 and 6.7%, respectively. The proposed method was satisfactorily applied for the determination of clomipramine in human plasma and urine.