Separation and determination of amitriptyline and nortriptyline by dispersive liquid-liquid microextraction combined with gas chromatography flame ionization detection

Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-flame ionization detection (GC-FID) was applied for the determination of two tricyclic antidepressant drugs (TCAs), amitriptyline and nortriptyline, from water samples. This method is a very simple and rapid method for the extraction and preconcentration of these drugs from environmental sample solutions. In this method, the appropriate mixture of extraction solvent (18 mu L Carbon tetrachloride) and disperser solvent (1 mL methanol) are injected rapidly into the aqueous sample (5.0 mL) by syringe. Therefore, cloudy solution is formed. In fact, it is consisted of fine particles of extraction solvent which is dispersed entirely into aqueous phase. The mixture was centrifuged and the extraction solvent is sedimented on the bottom of the conical test tube. 2.0 mu L of the sedimented phase is injected into the GC for separation and determination of TCAs. Some important parameters, such as kind of extraction and disperser solvent and volume of them, extraction time, pH and ionic strength of the aqueous feed solution were optimized. Under the optimal conditions, the enrichment factors and extraction recoveries were between 740.04-1000.25 and 54.76-74.02%, respectively. The linear range was (0.005-16 mu g mL(-1)) and limits of detection were between 0.005 and 0.01 mu g mL(-1) for each of the analytes. The relative standard deviations (R.S.D.) for 4 mu g mL(-1) of TCAs in water were in the range of 5.6-6.4 (n = 6). The performance of the proposed technique was evaluated for determination of TCAs in blood plasma. (C) 2008 Elsevier B.V. All rights reserved.