Efficient dispersive micro solid-phase extraction of antidepressant drugs by a robust molybdenum-based coordination polymer

A molybdenum-based coordination polymer {[Mo(PDA)(NO)(mu-O)MoO3]center dot 1.42H(2)O center dot 0.58C(2)H(5)OH}(n) (1) (PDA is 1,10-phenanthroline-2,9-dicarboxylate) was synthesized using solvothermal reaction conditions and characterized using a suite of analytical techniques. Single-crystal X-ray diffraction studies reveal a 1D chain structure, with close contacts expanding the structure into 3D including pi-interactions and hydrogen bonding. The utility of 1 as a sorbent for dispersive micro solid-phase extraction (D-mu SPE) of basic organic compounds such as antidepressants is supported by the presence of many functional groups on the surface of 1 (such as pendant carboxylates, Mo=O, Mo-NO, and CH groups) as well as extensive electrostatic interactions. Therefore, 1 can be a suitable choice as sorbent in the D-mu SPE of antidepressant drugs from human plasma samples via appreciable adsorbate-adsorbent interactions. Determination of the extracted antidepressant drugs was conducted using high-performance liquid chromatography-ultraviolet (HPLC-UV), with calibration plots being linear in the concentration range 0.1-500 ng mL(-1) for amitriptyline and nortriptyline, 0.2-500 ng mL(-1) for imipramine, and 0.5-300 ng mL(-1) for sertraline. The relative standard deviation (RSD) values were calculated for both intra-day and inter-day precision, and the RSD% values were in the range 3.9 to 5.2% and 4.6-5.4%, respectively. The limits of detection (LODs) was determined as 0.03-0.2 ng mL(-1). Due to the good stability and reusability of the sorbent, the adsorption capacity had no obvious decrease after being used 20 times. Finally, the D-mu SPE-HPLC-UV method was applied for the determination of antidepressant drugs in human plasma samples with recoveries of the analytes in the range 94.9 to 102%.