Preparation of two regional isomers self-crosslinked ionic liquid modified silica stationary phase for mixed-mode chromatography and its application for additive detection.

In this study, two self-crosslinked polymeric ionic liquids (SPILs) with varying chain lengths were immobilized onto silica surfaces via thiol-ene click reaction, and the synthesized stationary phases were subsequently applied to mixed-mode chromatographic separations. Comprehensive characterization using Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and elemental analysis (EA) confirmed the successful synthesis of two mixed-mode chromatographic stationary phases. The separation performance was systematically investigated by evaluating diverse analytes in reversed-phase liquid chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC), and ion exchange chromatography (IEC).

Fabrication of fluorinated and covalently self-crosslinked poly(ionic liquid)s modified silica gel and its application in analysis of cold medications and food components.

Background: Self-crosslinked poly(ionic liquid)s (CPIs), a subset of ionic liquids, are emerging functional polymeric materials with broad applications in catalysis and sensor technology. However, there are scant reports on the use of CPIs as high-performance liquid chromatography (HPLC) stationary phases. Fluorinated materials, noted for their unique physicochemical properties, have recently drawn interest in purification and separation fields.

Preparation of dicationic ionic liquid modified silica stationary phase for mixed-mode liquid chromatography and its application for food additive detection.

Background: Food safety has become an essential aspect of public concern and there are lots of detection means. Liquid chromatography plays a dominating role in food safety inspection because of its high separation efficiency and reproducibility. However, with the increasing complexity of real samples and monitoring requirements, conventional single-mode chromatography would require frequent column replacement and cannot separate different kinds of analytes on a single column simultaneously, which is costly and time-consuming.

Dicationic imidazole ionic liquid stationary phase for preservative detection and its application under mixed mode of HILIC/RPLC/IEC.

Background: Food safety has always been a great concern, and the detection of additives is vital to ensuring food safety. Therefore, there is a necessity to develop a method that can quickly and efficiently separate and detect additives in food. High performance liquid chromatography is widely used in the analysis and testing of food additives.

Preparation of two zwitterionic polymer functionalized stationary phases and comparative evaluation under mixed-mode of reversed phase/ hydrophilic interaction/ion exchange chromatography.

Zwitterions are a promising choice to prepare separation materials because of their hydrophilicity and biocompatibility. We described the preparation of two zwitterionic polymer functionalized stationary phases and evaluation under mixed-mode chromatography. A zwitterionic monomer, S-(4-vinylbenzyl) cysteine (SVC), was synthesized and bonded to silica via reversible addition fragmentation chain transfer (RAFT) polymerization to afford a zwitterionic stationary phase, Sil-SVC.

Fabrication of ionic liquid functionalized silica with different anions and the application in mixed-mode and chiral chromatography.

To realize the potential of ionic liquid functionalized silica to prepare mixed-mode and chiral stationary phases, two ionic liquid silane reagents with different anions were synthesized via a high-efficiency click reaction. Then they were decorated onto the surface of silica by a one-step bonding reaction. The functionalized silica was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and elemental analysis (EA).

Preparation of three structurally similar stationary phases with different ionizable terminal groups and evaluation of their retention performances under multiple modes in high performance liquid chromatography.

Three structurally similar silane reagents with different terminal groups were prepared and bonded to silica to obtain three structurally similar stationary phases (Sil-Ph-COOH, Sil-Phe and Sil-Ph-NH). The prepared stationary phases were characterized through elemental analysis (EA) and Fourier Transform Infrared Spectroscopy (FT-IR). These three stationary phases provided acceptable retention repeatability (relative standard deviations between 0.

Graft copolymerization of anion and cation onto silica and application in mixed-mode of reversed phase/ hydrophilic interaction/ ion exchange chromatography.

Ionic liquids (ILs) have turned out to be one of the best choices to fabricate mixed-mode stationary phases, this work aimed to investigate the possibility and merit of copolymerizing cations and anions as modifications. We prepared two ILs stationary phases, one of which was constructed by copolymerizing cation and anion (p-vinylbenzene sulfonate). Two stationary phases were characterized and comprehensively evaluated.

Preparation of three regioisomeric ionic liquid stationary phases and investigation of their retention behavior.

The structural properties of ionic liquid stationary phases have a considerable effect on their separation selectivity. However, the difference of the chromatographic retention behavior of different regioisomeric ionic liquid stationary phases has rarely been investigated. In this study, three regioisomeric ionic liquid silane reagents were prepared by photoinitiated ene-click chemistry and bonded to silica by one-pot method to fabricate three new stationary phases (Sil-C2Im-C8, Sil-C6Im-C4, and Sil-C9Im-C1).

Effect of spacer alkyl chain length on retention among three imidazolium stationary phases under various modes in high performance liquid chromatography.

The properties of ionic liquids (ILs) greatly influenced the retention of solutes on IL-functionalized stationary phases. In this work, three IL-functionalized stationary phases (Sil-C4Im, Sil-C7Im, and Sil-C10Im) were prepared by modifying silica gel with three ionic liquid silane reagents differing in spacer alkyl chain lengths, which refers to the alkyl chain between the imidazolium and the sulfur atom. The preparation was proved through a range of characterization techniques, including elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA).

Preparation of spherical silica hydroxyl-functionalized covalent organic polymer composites for mixed-mode liquid chromatography.

Covalent organic polymers are an emerging class of amorphous microporous materials that have raised increasing concerns in analytical chemistry due to their unique structural and surface chemical properties. However, the application of covalent organic polymers as mixed-mode stationary phases in chromatographic separations has rarely been reported. Herein, novel spherical silica hydroxyl-functionalized covalent organic polymer composites were successfully prepared via a layer-by-layer approach.

Solvent-dependent carbon dots for multifunctional sensing of temperature, pH, and proton pump inhibitors.

Multifunctional sensing, a strategy to improve the efficiency of analysis and detection, has attracted much attention. In this study, a multifunction sensing platform was developed for temperature, pH, and proton pump inhibitors (PPI) with fluorescence carbon dots. Solvent-dependent carbon dots (PG-CDs) were synthesized through a one-step solvothermal method from phloroglucinol with the assistance of HCl.

A ratiometric fluorescence sensor for ascorbic acid determination based on an AND-NAND logic pair.

An AND-NAND logic pair is reported based on non-purified carbon quantum dots (CDs) for ascorbic acid (AA) detection. In the logic operation, molybdenum oxide nanosheets (MoO NSs) and AA are used as two signal inputs. In the presence of AA, MoO NSs are reduced to plasmonic molybdenum oxide, which decreases the CD fluorescence intensity because of a static quenching, dynamic quenching, and internal filtration effect.

Facile fabrication of silica@covalent organic polymers core-shell composites as the mixed-mode stationary phase for hydrophilic interaction/reversed-phase/ion-exchange chromatography.

Covalent organic polymers (COPs) are a promising class of cross-linked polymeric networks that attracted extensive attention in separation and analysis fields. Exploring facile and convenient strategy to prepare COPs-based mixed-mode stationary phases for high performance liquid chromatography (HPLC) has seriously lagged and has never been reported. Herein, we describe a facile in-situ grow strategy for fabrication of silica@COPs core-shell composites (SiO@TpBD-(OH)) as a novel mixed-mode stationary phase for HPLC.

One-step synthesis of N-doped carbon dots, and their applications in curcumin sensing, fluorescent inks, and super-resolution nanoscopy.

Nitrogen-doped carbon dots (N-CDs) with fluorescence excitation/emission maxima at 365/450 nm were prepared by a one-step hydrothermal approach. The dots possess remarkable photostability, fluorescence blinking and good biocompatibility, and this favors utilization in stochastic optical reconstruction microscopy (STORM). A spatial resolution down to ~60 nm was achieved when imaging HeLa cells using 647-nm laser excitation.

Preparation of two ionic liquid bonded stationary phases and comparative evaluation under mixed-mode of reversed phase/ hydrophilic interaction/ ion exchange chromatography.

The present work describes the preparation of two ionic liquid and carboxyl acid silane reagents via photo-initiated thiol-ene click chemistry that have been bonded to silica to afford two mixed-mode stationary phases (Sil-C4Im-C9Co and Sil-C9Im-C4Co). The two stationary phases provided satisfactory retention repeatability and efficiencies. The influence of acetonitrile content, salt concentration and pH of the mobile phase was investigated to clarify the retention properties of the prepared stationary phases.

Simultaneous determination of cytokinins by high performance liquid chromatography with resonance Rayleigh scattering and mechanism discussion.

A reliable, highly sensitive and highly selective method of high performance liquid chromatography associated with resonance Rayleigh scattering (HPLC-RRS) was developed to detect three cytokinins, namely, 6-benzylaminopurine (BA), kinetin (KT) and zeatin (ZT). In this work, Pd(ii) is added into the system to form ternary ion association complexes for the first time, which results in a lower limit of detection and extends the application of HPLC-RRS. The experimental conditions were optimized.

A quadruple-channel fluorescent sensor array based on label-free carbon dots for sensitive detection of tetracyclines.

A quadruple-channel fluorescent sensor array based on label-free carbon dots (CDs) was fabricated to detect and discriminate a series of tetracyclines (TCs), including chlortetracycline (CTC), oxytetracycline (OTC), tetracycline (TC) and doxycycline (DOX). Blue-emitting carbon dots (B-CDs) and green-emitting carbon dots (G-CDs) were prepared to serve as four sensing elements. When the TCs were directly mixed with CDs, the fluorescence quenching phenomenon appeared.

High performance liquid chromatography associated with resonance Rayleigh scattering for synchronous determination of three antihistamines and mechanism study.

A highly sensitive and selective method of high performance liquid chromatography (HPLC) combined with resonance Rayleigh scattering (RRS) spectra was developed for the detection of three antihistamine drugs, including pyrilamine (PY), carbinoxamine (CAR) and tripelennamine (TRI). The three antihistamines were separated by a C18 column. The mobile phase contained 25% acetonitrile (ACN) and 75% phosphate buffered solution (pH 3.

Preparation and evaluation of surface-bonded phenylglycine zwitterionic stationary phase.

4-Hydroxy-D-phenylglycine was modified with methacrylic anhydride and then immobilized on silica through thiol-initiated surface polymerization; the prepared material was applied as stationary phase for HPLC. The obtained stationary phase was characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The chromatographic performance of the packed column was evaluated in reversed-phase liquid chromatograph (RPLC) and hydrophilic interaction liquid chromatograph (HILIC) mode; this column has shown excellent selectivity to both the hydrophobic and hydrophilic solutes.

High-performance liquid chromatography study of gatifloxacin and sparfloxacin using erythrosine as post-column resonance Rayleigh scattering reagent and mechanism study.

Herein, a highly selective high-performance liquid chromatography (HPLC) coupled with resonance Rayleigh scattering (RRS) method was developed to detect gatifloxacin (GFLX) and sparfloxacin (SPLX). GFLX and SPLX were first separated by HPLC, then, in pH 4.4 Britton-Robinson (BR) buffer medium, protonic quaternary ammonia cation of GFLX and SPLX reacted with erythrosine (ERY) to form 1:1 ion-association complexes, which resulted in a significant enhancement of RRS signal.

The fluorescence and resonance Rayleigh scattering spectra study on the interactions of palladium (II)-Nootropic chelate with Congo red and their analytical applications.

A highly sensitive detection approach of resonance Rayleigh scattering spectra (RRS) is firstly applied to analyzing nootropic drugs including piracetam (PIR) and oxiracetam (OXI). In HCl-NaAc buffer solution (pH=3.0), the OXI chelated with palladium (II) to form the chelate cation [Pd·OXI], and then reacted with Congo red (CGR) by virtue of electrostatic attraction and hydrophobic force to form binary complex [Pd·OXI].

Study on the interaction between three benzimidazole anthelmintics and eosin Y by high performance liquid chromatography associating with resonance light scattering and its application.

A novel, highly selective, and sensitive resonance light scattering (RLS) detection approach coupled with high performance liquid chromatography (HPLC) was researched and developed for the synchronous analysis of three kinds of benzimidazole anthelmintics, including mebendazole (MBZ), albendazole (ABZ), and fenbendazole (FBZ) for the first time. In the pH range of 3.5-3.

Resonance Rayleigh scattering technique as a detection method for the RP-HPLC determination of local anaesthetics in human urine.

A highly selective and sensitive method of reversed phase high-performance liquid chromatography (RP-HPLC) coupled with resonance Rayleigh scattering (RRS) was developed for the determination of procaine, bupivacaine and tetracaine. Separation of three local anaesthetics was achieved at 35 °C on a C column. The mobile phase was 30: 70 (v/v) acetonitrile/triethylamine-phosphoric acid buffer (pH 2.