ANALYTICAL CHEMISTRY
·
2014
·
IF 5.825
Jun-Hui Zhang,Sheng-Ming Xie,Mei Zhang,Min Zi,Pin-Gang He,Li-Ming Yuan
Chiral nematic mesoporous silica (CNMS) has attracted widespread attention due to some unique features, such as its nematic structure, chirality, large pore size, high temperature resistance, low cost, and ease of preparation. We first reported the use of CNMS as a stationary phase for capillary gas chromatography (GC). The CNMS-coated capillary column not only gives good selectivity for the separation of linear alkanes, aromatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and isomers but also offers excellent enantioselectivity for chiral compounds. Compared with enantioseparations on commercial β-DEX 120 and Chirasil-l-Val columns, a CNMS-coated capillary column offers excellent enantioselectivity, chiral recognition complementarity, and the separation of analytes within short elution times. It can also be potentially applied in high-temperature GC at more than 350 °C. This work indicates that CNMS could soon become very attractive for separations.
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高影响因子
ANALYST
·
2013
·Vol. 139
·期 1
·242-250
·
IF 3.969
Juan Zhang,Wenpeng Zhang,Tao Bao,Zilin Chen
A novel capillary with hydroxyapatite (HAP) as the stationary phase was prepared for open-tubular capillary electrochromatography (OT-CEC). To immobilize HAP, a mussel-inspired polydopamine method was utilized to modify the capillary firstly, generating a polydopamine layer; and then a layer of HAP would be formed on the polydopamine layer by a biomineralization process, to produce a HAP-modified capillary (HAP@capillary). Scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) provided evidence of nanostructured HAP grown on the surface of the capillary wall. The electroosmotic flow (EOF) characteristic of the HAP@capillary was investigated by varying the percentage of acetonitrile and pH value of the buffer with thiourea as a marker, and a pH-dependent EOF from anode to cathode was observed. The HAP@capillary exhibits high column efficiency for methylbenzene, up to 151 138 plates per meter. Different kinds of compounds including alkylbenzenes, phenols and amines have been successfully separated by the HAP@capillary in CEC mode. The HAP@capillary also possessed good separation ability in capillary liquid chromatography (CLC) mode because of the relatively large ratio of HAP in the capillary; however, the separation efficiency was not as good as that in CEC mode. The reproducibilities of the HAP@capillary were evaluated, and the relative standard deviations were found to be lower than 5%.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Yang Liu,Jian Li,Jiawei Liu,Changwei Tang,Quan Bai
Metal-organic frameworks (MOFs) are promising packing materials in liquid chromatography, but their micropore character extremely prevents the separation performance. Herein, we proposed an acidic etching strategy to fabricate a hierarchically porous University of Oslo-66 (HP-UiO-66) coated silica shell-core composite by using phosphoric acid as an etchant. The prepared composite, namely HP-UiO-66@silica-PA, was characterized by SEM, TEM, FT-IR, and N 2 -adsorption–desorption isotherms, demonstrating the generation of mesopores in HP-UiO-66 shell with pore width ranging in 4–5 nm. The chromatographic performance of HP-UiO-66@silica-PA-1 (etched by 1 mL phosphoric acid for 2 h) as HPLC stationary phase was evaluated in reversed-phase mode, and the separations of three groups of small solutes were studied and compared with the microporous UiO-66@silica (MP-UiO-66@silica) column. The results proved the obviously improved performances with narrower peak width, better resolution, and higher symmetry were achieved by the HP-UiO-66@silica-PA-1 column. The faster diffusion and mass transfer kinetics in the HP-UiO-66 shell signally reduce the plate height and improve the column efficiency. Specifically, the plate number of o -xylene was 18,442 plates m −1 , which was about 18.5 times higher than that on the MP-UiO-66@silica column (993 plates m −1 ). Furthermore, good repeatability and reproducibility with RSDs of both retention time and peak area less than 0.5 % confirmed the high stability and outstanding reliability of the HP-UiO-66@silica-PA-1 column. This study demonstrates that the phosphoric acid etching strategy is simple, mild, and controllable to fabricate hierarchically porous MOFs-based stationary phase for enhancing the HPLC separation performance.
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NEW JOURNAL OF CHEMISTRY
·
2024
·
IF 2.7
Yufen Wang,Yantao Wang,Yongqing Ma,Asma Mohmmad Elsharif,Chen Zhang,Weiran Yang,Christophe Len
A new transition-metal-free catalytic system which uses sodium iodide as the catalyst with formic acid as the hydrogen donor in a biphasic medium was reported for the reduction of the hydroxyl group and various unsaturated groups such as CC, CC, CN and CO. Using the same catalytic system, reductive N-formylation of nitroarenes with formic acid was explored to produce the corresponding amide in high selectivity. Moreover, the catalyst stability was evaluated and reaction mechanisms were studied and proposed for the three model reactions.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yixin Kuang,Suxin Zhou,Cheng Mao,Xiaoying Feng,Juan Zheng,Gangfeng Ouyang
High-resolution separation of numerous isomers is highly desirable for their high-quality analysis, yet challenging, which puts forward high requirements on the precise design of stationary phase. Herein, flexible 4- tert -butylcalix[n]arenes (TBCx[n]s) with different cavities have been intelligently integrated with in-situ grown UiO-66 coatings, to investigate their separation efficiencies for alkane and substituted benzene isomers. The modifications of UiO-66 with TBCx[n]s have made up for the deficiency of UiO-66 on the separation of ethylbenzene and styrene. The effects of TBCx[n]s on the separation performance of UiO-66@TBCx[n]s have demonstrated distinct regularities, i.e., the effects of TBCx[6] are superior to those of TBCx[8], while the TBCx[4] is the least effective. The baseline separation of all analytes has been achieved by the UiO-66@TBCx[6] column with enhanced selectivity and improved separation resolution (Rs). For the six groups of isomers that are most difficult to separate, the corresponding selectivity and Rs are greater than 1.09 and 5.48, respectively, confirming the outstanding separation performance of the UiO-66@TBCx[6] column and the feasibility of integrating soft supramolecule and rigid MOF.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2024
·
IF 3.8
Liao Zhengzheng,Hu Jinfang,Li Zhentao
CD-MONs (β-cyclodextrin-based microporous organic networks), derived from β-cyclodextrin, possess notable hydrophobic characteristics, a considerable specific surface area, and remarkable stability, rendering them highly advantageous in separation science. This research aimed to investigate the utility of CD-MONs in chromatography separation. Through a monomer-mediated technique, we fabricated an innovative CD-MON modified capillary column for application in open-tubular capillary electrochromatography (OT-CEC). The CD-MON-based stationary phase on the capillary’s inner surface was analyzed using Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). We assessed the performance of the CD-MON modified capillary column for separation purposes. The microstructure and pronounced hydrophobicity of CD-MON contributed to enhanced selectivity and resolution in separating diverse hydrophobic analytes, such as alkylbenzenes, halogenated benzenes, parabens, and polycyclic aromatic hydrocarbons (PAHs). The maximum column efficiency achieved was 1.5 × 10 5 N/m. Additionally, the CD-MON modified capillary column demonstrated notably high column capacity, with a methylbenzene mass loading capacity of up to 197.9 pmol, surpassing that of previously reported porous-material-based capillaries. Furthermore, this self-constructed column was effectively utilized for PAHs determination in actual environmental water samples, exhibiting spiked recoveries ranging from 93.2 to 107.9% in lake water samples. These findings underscore the potential of CD-MON as an effective stationary phase in separation science. Graphical Abstract
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JOURNAL OF CHROMATOGRAPHY A
·
2024
·
IF 3.8
Yiran Xia,Lushuai Wang,Yang Liu,Jiawei Liu,Quan Bai
Covalent organic frameworks (COFs) show promise as a stationary phase in high performance liquid chromatography (HPLC). However, there are only a few COFs-based stationary phases developed for HPLC separation so far. Therefore, it is crucial to not only develop more varieties of COFs-type stationary phases for HPLC separation, but also to explore the retention mechanism of solutes on these stationary phases. In this paper, a new in-situ growth method was developed to prepare β -ketoenamine COF-TpPa-1@SiO 2 composite microspheres, using spherical silica as the core material and COF-TpPa-1 fabricated by covalent conjugation of 1,3,5-triformylphloroglucinol (Tp) and p -phenylenediamine (Pa-1) as the COF shells. The resulting microspheres exhibit uniform morphology, good monodispersity, large specific surface area, narrow size distribution, and high stability. Due to diverse functional groups in the structure of COF-TpPa-1, the microspheres can offer multiple interactions, such as hydrophobic, π-π stacking and electron-donor–acceptor (EDA) between COFs and analytes. As a result, the COF-TpPa-1@SiO 2 composite microspheres can be used as a mixed-mode stationary phase for HPLC separation. The chromatographic performance and retention mechanism of the COF-TpPa-1@SiO 2 packed column were investigated by separating polar and non-polar solutes, as well as isomers, in various HPLC modes, including reversed-phase liquid chromatography (RPLC), hydrophilic interaction chromatography (HILIC), and RPLC/HILIC mixed-mode chromatography. The results showed successful separation of non-polar alkylbenzene homologues, polycyclic aromatic hydrocarbons (PAHs), and polar amines and phenols in RPLC mode. The “U-shaped” curves of retention factor with the ACN concentration in mobile phase for four nucleobases indicated that the solute retention on the column followed a mixed mode mechanism of RPLC/HILIC. Compared to a traditional C18 column, the COF-TpPa-1@SiO 2 column exhibited superior separation efficiency, stability, repeatability and reproducibility in the separation of analytes with different polarities. The column enhanced the aromatic, shape and planar selectivity for PAHs and isomers through π-π interaction and improved the separation efficiency for electron-deficient compounds due to EDA effect. At last, the column was successfully used to separate and detect the residues of 5 phenylurea herbicides (PUHs) in soil. All these results indicate the potential of COFs for chromatography applications.
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Advanced Science
·
2025
·
IF 14.1
Yanyan Yu,Yilin Li,Yuhan Lou,Mengyuan Chen,Yongzhuang Liu,Haipeng Yu
Catalytic refining of lignin holds promise for producing sustainable platform chemicals. In this work, a gaseous hydrogen-free catalytic hydrodeoxygenation system is developed for upgrading lignin-derived phenols to alkane chemicals. Commercially available Raney Ni and HZSM-5 are used as a combinational catalyst, with isopropanol serving as the hydrogen-donating solvent. By modifying the temperature and the ratio of Raney Ni to HZSM-5, the reaction pathways for hydrogenation and deoxygenation can be tailored to specific requirements. As a result, a 97.1% yield of alkane fuels is achieved, with 64.4% propylcyclohexane and 32.7% propylbenzene obtained in one-pot reaction from the hydrodeoxygenation of 2-methoxy-4-propylphenol using a 3:1 mass ratio of Ni to HZSM-5, further increasing the ratio of HZSM-5 leads to a selectively production of propylbenzene in 62.0% yield. Through careful regulation of the catalytic system and the design of hydrogenation–deoxygenation pathways, excellent yields of 4-propylcyclohexanol (92.2%), propylcyclohexene (93.3%), and propylcyclohexane (93.2%) are directionally achieved. The catalyst maintained a conversion rate of over 99% after five cycles, demonstrating excellent robustness. This study offers a strategic system that expedites the selective upgrading of lignin-derived chemicals, heralding a pathway toward sustainable fuels and chemicals.
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JOURNAL OF CHROMATOGRAPHY A
·
2025
·
IF 4
Zhipeng Zhu,Min Zhang,Xiaohui Yan,Chenglong Shi,Bin Wang,Yanshuo Li,Dapeng Wu
A crosslinked polystyrene-divinylbenzene (PS-DVB) stationary phase was prepared onto silica gel with the pore size of 100 Å and 300 Å (SiL-PSD-10, SiL-PSD-30) by surface-initiated atom transfer radical polymerization (ATRP) for high performance liquid chromatography (HPLC) separation of alkylbenzenes, fullerites, and proteins, respectively. The SiL-PSD coating and the pore size distribution were characterized by FT-IR, TGA, and nitrogen adsorption-desorption isotherms. The crosslinking degree within stationary phase was determined in good consistency with the feeding ratio, as confirmed by RP-HPLC. It was found the SiL-PSD-10 particles could resist the harsh etching of 0.1 M NaOH for at least 6 h, while bare silica was totally dissolved and commercial C18 silica was partially dissolved under the same conditions. Under alkaline conditions (pH 11), the column bleeding rates of SiL-PSD-10 were reduced by 83 % and 96.0 % respectively compared to commercial C18 column and bare silica. Under accelerated aging conditions, SiL-PSD-10 maintained over 94 % of its initial column efficiency after exposure to 16,000 column volume of mobile phase. On SiL-PSD columns, alkylbenzenes could be separated in reversed-phase mode, and fullerite (C 60 /C 70 ) could be baseline resolved within 2 min with benzene as the mobile phase. During the continuous monitoring for 70 h, RSDs of the retention times of proteins were between 0.49 % and 1.19 %. Generally, SiL-PSD had been demonstrated to combine the excellent mechanical strength and uniform porosity of silica gel with the outstanding chemical resistance of PS-DVB, and could be used for HPLC separation across a wider pH.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2025
·
IF 3.8
Sun Tao,Shen Xin,Yang Xinyu,Qi Haolong,Yang Kexin,Xing Yilin,You Mengyi,Duan Mengyao,Cai Zhiqiang,Nardiello Donatella,Quinto Maurizio,Liu Xianming,Zhang Shusheng
Cyclotriveratrylene (CTV) possesses a rigid and bowl-shaped architecture with a π -electron-rich cavity. In this work, CTV modified with C10 alkyl chains (CTV-C10) has been synthesized and used for the first time as a stationary phase for gas chromatography (GC) analysis. The statically coated CTV-C10 column showed moderate polarity and high column efficiency (3446 plates m −1 , determined by n -dodecane at 120 °C). Due to its nanoscale channels, the CTV-C10 column displayed a strong affinity for aromatic compounds. Compared with CTV and commercial HP-5 and HP-35 columns, the CTV-C10 column exhibited better performance for the critical resolution of dibromobenzene, dichlorobenzene, and chloronitrobenzene isomers. Moreover, CTV-C10 columns showed 0.02%, 0.09%, and 4.96% repeatability RSD values for intra-day, inter-day, and between-columns, respectively. This study demonstrated the feasibility of CTV-C10 columns, providing a new perspective for developing selective nanoscale separation channels through CTV stationary phases in chromatographic analysis. Graphical abstract
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MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Dan Wang,Yuanmin Gong,Meiting Yan,Jiaqi Chen,Xueping Tao,Yang Zhou,Yan Ma,Li Rao,Panpan Chen,Qifeng Fu
Carbon dots (CDs) hold great potential for chromatographic separations. However, their application in chromatographic stationary phases has been limited by two major synthetic challenges: (1) insufficient control over surface chemoselectivity caused by impurity co-adsorption, and (2) structural heterogeneity arising from uncontrolled solvothermal byproducts. To address these limitations, we developed a self-polymerization-driven strategy to synthesize high-purity hydrophobic CDs from 8-amino-2-naphthol (8N2OH) and 2,3-dihydroxynaphthalene (DHN). These CDs were incorporated into organic polymer monoliths via in situ copolymerization, yielding novel 8N2OH-CDs and DHN-CDs hybrid monolithic stationary phases for reversed-phase capillary liquid chromatography. The synthesized CDs were thoroughly characterized, with high purity confirmed by proton nuclear magnetic resonance. The resulting monolithic columns exhibited high permeability and uniformity, as demonstrated by field emission scanning electron microscopy, attributed to the excellent dispersion of the CDs. The chromatographic performance was evaluated using nine types of neutral, alkaline, and acidic compounds, as well as Tanaka standard test mixtures. Compared to unmodified columns, the CD-modified monoliths showed significantly enhanced retention strength and selectivity, supported by Tanaka tests revealing multifactorial retention mechanisms. This work demonstrates the potential of high-purity hydrophobic CDs as versatile modifiers for high-performance chromatographic stationary phases.
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ELECTROPHORESIS
·
2015
·Vol. 36
·期 17
·2120-2127
·
IF 3.028
Lu Yangfang,Wang Hui,Xue Yun,Gu Xue,Wang Yan,Yan Chao
Submicron, non-porous, chiral silica stationary phase has been prepared by the immobilization of functionalized β-CD derivatives to isocyanate-modified silica via chemical reaction and applied to the pressurized capillary electrochromatography (pCEC) enantio-separation of various chiral compounds. The submicron, non-porous, cyclodextrin-based chiral stationary phases (sub_μm-CSP2) exhibited excellent chiral recognition of a wide range of analytes including clenbuterol hydrochloride, mexiletine hydrochloride, chlorpheniramine maleate, esmolol hydrochloride, and metoprolol tartrate. The synthesized submicron particles were regularly spherical and uniformly non-porous with an average diameter of around 800 nm and a mean pore size of less than 2 nm. The synthesized chiral stationary phase was packed into 10 cm × 100 μm id capillary columns. The sub_μm-CSP2 column used in the pCEC system showed better separation of the racemates and at a higher rate compared to those used in the capillary liquid chromatography mode (cLC) system. The sub_μm-CSP2 possessed high mechanical strength, high stereoselectivity, and long lifespan, demonstrating rapid enantio-separation and good resolution of samples. The column provided an efficiency of up to 170 000 plates/m for n -propylbenzene.
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