In Situ Synthesis of MIL-100(Fe) in the Capillary Column for Capillary Electrochromatographic Separation of Small Organic Molecules

Because of the unusual properties of the structure, the metal organic frameworks (MOFs) have received great interest in separation science. However, the most existing methods for the applications of MOFs in separation science require an off-line procedure to prepare the materials. Here, we report an in situ, layer-by-layer self-assembly approach to fabricate MIL-100­(Fe) coated open tubular (OT) capillary columns for capillary electrochromatography. By a controllable manner, the OT capillary columns with a tailored MIL-100­(Fe) coating have been successfully synthesized. The results of SEM, XRD, FT-IR, and ICP-AES indicated that MIL-100­(Fe) was successfully grafted on the inner wall of the capillary. Some neutral, acidic and basic analytes were used to evaluate the performance of the MIL-100­(Fe) coating OT capillary column. Because of the size selectivity of lattice aperture and hydrophobicity of the organic ligands, three types of analytes were well separated with this novel MIL-100­(Fe) coating OT capillary column. For three consecutive runs, the intraday relative standard deviations (RSDs) of migration time and peak areas were 0.4–4.6% and 1.2–6.6%, respectively. The interday RSDs of migration time and peak areas were 0.6–8.0% and 2.2–9.5%, respectively. The column-to-column reproducibility of retention time was in range of 0.6–9.2%. Additionally, the 10 cycles OT capillary column (10-LC) could be used for more than 150 runs with no observable changes on the separation efficiency

Solid-Phase Synthesis of Highly Fluorescent Nitrogen-Doped Carbon Dots for Sensitive and Selective Probing Ferric Ions in Living Cells

Carbon quantum dots (C-Dots) have drawn extensive attention in recent years due to their stable physicochemical and photochemical properties. However, the development of nitrogen-doped carbon quantum dots (N-doped C-Dots) is still on its early stage. In this paper, a facile and high-output solid-phase synthesis approach was proposed for the fabrication of N-doped, highly fluorescent carbon quantum dots. The obtained N-doped C-Dots exhibited a strong blue emission with an absolute quantum yield (QY) of up to 31%, owing to fluorescence enhancement effect of introduced N atoms into carbon dots. The strong coordination of oxygen-rich groups on N-doped C-Dots to Fe³⁺ caused fluorescence quenching via nonradiative electron-transfer, leading to the quantitative detection of Fe³⁺. The probe exhibited a wide linear response concentration range (0.01–500 μM) to Fe³⁺ with a detection limit of 2.5 nM. Significantly, the N-doped C-Dots possess negligible cytotoxicity, excellent biocompatibility, and high photostability. All these features are favorable for label-free monitoring of Fe³⁺ in complex biological samples. It was then successfully applied for the fluorescence imaging of intracellular Fe³⁺. As an efficient chemosensor, the N-doped C-Dots hold great promise to broaden applications in biological systems

Identification, characterization, and synthesis of process-related impurities in antiproliferative agent TQ-B3203

<p>Liposoluble camptothecin derivative, research name TQ-B3203, is a recently developed investigational antiproliferative agent by our group. The structure of TQ-B3203 is 2-(hexadecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate, containing an SN-38 component, a trolox component, a succinic acid linker, and a hexadecanol chain. In this study, the process-related impurities of bulk TQ-B3203 were identified, characterized, and synthesized. Seven major impurities were revealed based on the mass spectrum (MS) and nuclear magnetic resonance (NMR) spectral data. They were characterized as SN-38 (IMP-I), trolox (IMP-II), 2-(dodecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate (IMP-III), hexadecyl 7-ethyl-camptothecin-10-yl succinate (IMP-IV), 2-(tetradecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate (IMP-V), 4-(2-(hexadecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yloxy)-4-oxobutanoic acid (IMP-VI), and 4-(2-(octodecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yloxy)-4-oxobutanoic acid (IMP-VII). The probable origin of the impurities from the preparation process of TQ-B3203 was discussed.</p