Dispersive micro-solid-phase extraction (DMSPE) combined with dispersive liquid–liquid microextraction based on the solidification of a floating organic droplet (DLLME-SFO) was successfully developed for extraction and depuration of pantoprazole in rat plasma. The remarkable metal organic framework (MOF), MIL-101(Cr) was used as DMSPE adsorbent. The detection of pantoprazole was performed by convenient HPLC-UV. In the extraction of pantoprazole from plasma samples, small molecule compounds, including the target and abundant impurities, were easily admitted into the porous structure of MIL-101 (Cr) material in DMSPE; while, macromolecular compounds were handily excluded from the adsorbent. Next, the depuration process was achieved by removal of small polar impurities in DLLME-SFO. Influential factors were systematically optimized for ideal enrichment and depuration efficiency. Under the optimal conditions, a satisfactory linearity range from the lower limit of quantification (LLOQ, 100 ng/L) to 10 000 ng/L with the correlation coefficients ( r ) of 0.9934 was obtained. The LLOQ was 100 ng/mL and the relative recoveries were ≧ 73.2 ± 4.8%. The approving reproducibility, acceptable accuracy, and stability were all within the acceptance limits. This proposed method presented the advantages of environment-friendly, low-cost, recyclable, low impurity, and preferable applicability. It could offer a new idea for the pretreatment and pharmacokinetic study of pantoprazole in rat plasma.
The authors describe boronate-modified hollow dummy template imprinted polymers (B-hDIPs) for selective and sensitive extraction of the catecholamines norepinephrine (NE), epinephrine (E), and dopamine (DA) from urine samples prior to their detection by HPLC with UV detector. The B-hDIPs were prepared by using (a) nano-TiO 2 as the sacrificial support, (b) 3-carboxyphenylboronic acid (CPBA) as the boronate-affinity functional monomer, and (c) catechol which acts as dummy template. The nano-TiO 2 can be etched off by using hydrofluoric acid to form the hollow imprint. The main advantages of using such hollow polymers arise from their controllable hole structure which favors template removal and fast mass transfer. The B-hDIPs material was characterized by FT-IR, transmission electron microscope, dynamic light scattering, X-ray photoelectron spectrum, and thermal gravimetric analysis. The effects of imprinting conditions, sample pH, sample flow rate, adsorbent amount, selectivity and competitive capacities were investigated. Under optimal conditions, the limits of detection for the catecholamines are in the range from 15 to 47 ng mL −1 . The method was successfully applied to their determination of NE, E, and DA in spiked urine, with recoveries ranging from 63.4 to 106.2%.
Schematic presentation of boronate-modified hollow dummy template imprinted polymers as an adsorbent to extraction of the catecholamines (norepinephrine, epinephrine, and dopamine) from urine samples prior to their detection by HPLC-UV.