A stable and porous amino-functionalized zirconium-based metal organic framework (Zr-MOF-NH2) containing missing linker defects was prepared and fully characterized by FTIR, scanning electron microscopy, powder X-ray diffraction, and BET surface area measurement. The Zr-MOF-NH2 was then applied as an adsorbent in pipette-tip solid phase extraction (PT-SPE) of carbamazepine. Important parameters affecting extraction efficiency such as pH, sample volume, type and volume of eluent, amount of adsorbent, and number of aspirating/dispensing cycles for sample solution and eluent solvent were investigated and optimized. The best extraction efficiency was obtained when pH of 100 µL of sample solution was adjusted to 7.5 and 5 mg of the sorbent was used. Eluent solvent was 10 µL methanol. Linear dynamic range was found to be between 0.1 and 50 µg L−1 and limit of detection for 10 measurement of blank solution was 0.05 µg L−1. This extraction method was coupled to HPLC and was successfully employed for the determination of carbamazepine in urine and water samples. The strategy combined the advantages of fast and easy operation of PT-SPE with robustness and large adsorption capacity of Zr-MOF-NH2.

A novel tantalum metal organic framework (Ta-MOF) was synthesized by a microwave assisted reverse micelle procedure, and it was used as a sorbent for pipette tip micro-solid phase extraction of nicotine from biological and environmental samples. Several parameters that influence the extraction efficiency, such as the amount of sorbent, the volumes of sample solution and eluent solvent, the type of eluent, and the number of draw/eject cycles of sample solution and eluent solvent, were studied and optimized. The results showed that the highest extraction efficiency was obtained when 5 mg Ta-MOF was placed into a 20 μL pipette tip and 3500 μL of 5 mg L⁻¹ nicotine solution aspirated and dispensed over the sorbent after 15 cycles. The adsorbed nicotine was washed from the sorbent using 15 μL of methanol/ammonia solution as an eluent solvent with 20 draw/eject cycles. The linear dynamic range of this method was between 2 and 3000 μg L⁻¹ and the limit of detection and the limit of quantification were 0.7 and 4.8 μg L⁻¹, respectively. Intraday and interday precision expressed as relative standard deviation were good and found to be 2.7% and 5.2%, respectively. Finally, the method was successfully applied for the analysis of nicotine in six real samples of human saliva, urine and wastewater.