CHROMATOGRAPHIA
·
2013
·Vol. 76
·期 23
·1569-1576
·
IF 1.437
Cheng Xiao-Dong,Peng Xi-Tian,Yu Qiong-Wei,Yuan Bi-Feng,Feng Yu-Qi
A new stationary phase which contains both negatively charged phosphate groups and positively charged amino groups was successfully synthesized by modification of amino-functionalized silica particles with trichlorophosphine oxide (POCl 3 ) for hydrophilic interaction chromatography (HILIC). The composition of the surface grafts was determined by Fourier transform infrared spectroscopy and elemental analysis. Various parameters, such as column temperature, water content, pH values and ionic strength of the mobile phase were investigated to study the retention mechanism. The results demonstrated that the stationary phase involved a complex retention process including surface adsorption, partitioning and electrostatic interactions. Under optimized conditions, the separation of nucleobases and nucleosides, water-soluble vitamins, organic acids on the novel stationary phase could be achieved in the HILIC mode.
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RSC Advances
·
2015
·Vol. 5
·期 110
·90457-90465
·
IF 3.84
Shicai Xu,Jihua Wang,Yan Zou,Hanping Liu,Guiying Wang,Xiumei Zhang,Shouzhen Jiang,Zhen Li,Dongyan Cao,Rongxia Tang
An efficient surface enhanced Raman scattering (SERS) substrate of graphene-isolated Ag nanoparticle (G/AgNP) has been developed by using excimer laser to ablate the ordered pyrolytic graphite in high vacuum onto Ag nanoparticles. By combining the electromagnetic activity of AgNPs and unique physical/chemical properties of graphene, the G/AgNP substrates shows high performance in terms of sensitivity, signal-to-noise ratio and reproducibility. The average enhancement factor obtained from the G/AgNP substrates for rhodamine 6G probe molecules is over 108. The maximum deviations of SERS intensities from 20 positions of a same SERS substrate are in the range of 4.20% to 6.75% and from 20 different substrates in various batches are in the range of 4.43% to 7.71%, depending on different vibration modes. As a practical application of this SERS system, we detect the adenosine concentration in human serum. The detection results show a good linear correlation between SERS intensity and adenosine concentration within the range of 2 to 200 nM. This work may open up new opportunities in developing the applications of SERS in biomedical diagnostics, biological sensing and other biotechnology.
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TALANTA
·
2015
·
IF 3.545
Qing Wang,Yao Long,Lin Yao,Li Xu,Zhi-Guo Shi,Lanying Xu
A mixed-mode chromatographic stationary phase , C18-DTT (dithiothreitol) silica (SiO 2 ) was prepared through “thiol-ene” click chemistry. The obtained material was characterized by fourier transform infrared spectroscope, nitrogen adsorption analysis and contact angle analysis. Chromatographic performance of the C18-DTT was systemically evaluated by studying the effect of acetonitrile content, pH, buffer concentration of the mobile phase and column temperature. It was demonstrated that the novel stationary phase possessed reversed phase liquid chromatography (RPLC)/hydrophilic interaction liquid chromatography (HILIC) mixed-mode property. The stop-flow test revealed that C18-DTT exhibited excellent compatibility with 100% aqueous mobile phase. Additionally, the stability and column-to-column reproducibility of the C18-DTT material were satisfactory, with relative standard deviations of retention factor of the tested analytes (verapamil, fenbufen , guanine , tetrandrine and nicotinic acid) in the range of 1.82–3.72% and 0.85–1.93%, respectively. Finally, the application of C18-DTT column was demonstrated in the separation of non-steroidal anti-inflammatory drugs, aromatic carboxylic acids , alkaloids, nucleo-analytes and polycyclic aromatic hydrocarbons . It had great resolving power in the analysis of various compounds in HILIC and RPLC chromatographic conditions and was a promising RPLC/HILIC mixed-mode stationary phase.
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BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Ying Zhu,Xiao-chun Hu,Shuo Shi,Ru-ru Gao,Hai-liang Huang,Yan-yan Zhu,Xiao-yan Lv,Tian-ming Yao
We report here an ultrasensitive strategy based on the recognition-induced conformational alteration of aptamer and fluorescence turn-on abilities of guanine-rich (G-rich) DNA sequence in proximity to silver nanoclusters for adenosine triphosphate (ATP), adenosine (A) and thrombin (TB) detection. Herein, we designed two tailored DNA sequences noted as complementary DNA (abbreviated as c-DNA) and signal probe DNA (abbreviated as s-DNA), respectively. c-DNA is designed as a special structure consisting of a sequence complementary to aptamer at the 3′-end and a guanine-rich DNA sequence at the 5′-end; s-DNA contains a cytosine-rich sequence responsible for Ag NCs templated synthesis at the 3′-end and a link sequence (part of aptamer) complementary to partial of the c-DNA at the 5′-end. In the presence of target, the aptamer associated with the target, resulting in the formation of duplex DNA (dsDNA), the DNA–Ag NCs thereafter could close to the guanine-rich sequence, leading to enhanced fluorescence signal readout. The widespread application of the sensing system is achieved success in the detection of three biomolecules . ATP, adenosine and thrombin in the range of 0.5-8.0 μM, 0.5-7.0 μM and 50-900 nM could be linearly detected with the detection limits of 91.6 nM, 103.4 nM and 8.4 nM, respectively. This label-free and turn-on fluorescent sensing system employing the mechanism proposed here turns out to be sensitive, selective, and convenient for the detection of biomolecules without washing and separation steps.
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RSC Advances
·
2015
·Vol. 5
·期 128
·106161-106170
·
IF 3.84
Li Gao,Jin Du,Chaozhan Wang,Yinmao Wei
Boronate adsorbents have been widely used in the extraction of cis-diol-containing molecules, but most do not have efficient capacity due to limited binding sites on their surface. In this work, a high binding capacity dendrimer-modified boronate affinity material (SiO2@dBA) was synthesized via introducing tris(2-aminoethyl)amine as branching points and using poly(amidoamine) as the main dendrimeric scaffold before modification by boronate groups. The high density of amino groups on the dendrimer supplied a large number of binding sites for modifying boronate groups. Thus the adsorption capacity (676.8 μmol g−1 for catechol, 771.3 μmol g−1 for dopamine, 770.0 μmol g−1 for adrenaline) of SiO2@dBA was greatly improved. Moreover, when coupled with large-volume injection and online column-switching solid phase extraction, SiO2@dBA was able to capture cis-diols from 10 000-fold interference and enrichment factors reached up to 497–514, which was 26- to 51-fold higher than those of analogous non-dendrimer materials. Especially, the proposed method exhibited a striking low limit of detection, 0.24 ng mL−1 for cytidine, 0.52 ng mL−1 for uridine, 0.37 ng mL−1 for guanosine, 0.67 ng mL−1 for adenosine. Finally, the method was successfully applied to online determination of trace nucleosides in healthy human urine. In conclusion, the prepared adsorbent has potential to effectively enrich a large range of trace cis-diol substances in real samples.
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ANALYTICA CHIMICA ACTA
·
2015
·
IF 4.513
Chaozhan Wang,Huanhuan Xu,Yinmao Wei
Boronate affinity adsorption is uniquely selective for cis-diol-containing molecules. The preparation and application of boronate affinity materials has attracted much attention in recent years. In this work, a high-capacity boronate affinity adsorbent was prepared by surface-initiated reversible addition–fragmentation chain transfer polymerization (SI-RAFT). Commercial aminated poly(glycidyl methacrylate) (PGMA) microspheres were modified with the chain transfer agent (CTA) S-1-dodecyl-S-(α,α-dimethyl-α-acetic acid)trithiocarbonate (DDATC). Boronate-affinity adsorbents were then prepared via SI-RAFT polymerization employing 3-acrylamidophenylboronic acid (AAPBA) as the monomer . The Fourier transform infrared spectroscopy (FT-IR), nitrogen adsorption and desorption measurements have proven the successful grafting of AAPBA on PGMA microspheres surface. The boronate affinity adsorbents thus prepared possess much higher adsorption capacity (99.2 µmol/g of adenosine) and both faster adsorption and desorption speed towards ribonucleosides , the adsorption and desorption could be completed in 2 min. The high selectivity of the adsorbents to ribonucleosides was verified in the presence of a large excess of deoxynucleosides. The boronate affinity adsorbents were then employed for sample pretreatment before HPLC analysis of ribonucleosides in serum. The ribonucleosides were effectively enriched by boronate affinity dispersive solid-phase extraction (BA-DSPE), with high mass recoveries and good precision. The simultaneous determination of uridine and guanosine in calf serum was achieved by utilizing the standard addition method, their contents were determined to be 170 ± 11.6 ng/mL and 39.6 ± 4.4 ng/mL respectively. The results proved that the prepared boronate affinity materials could be applied for sample pretreatment of cis-diol containing molecules in biological samples.
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Nature Communications
·
2017
·Vol. 8
·期 1
·1-15
·
IF 12.124
Wu Liufeng,Meng Jia,Shen Qing,Zhang Yi,Pan Susu,Chen Zhuo,Zhu Ling-Qiang,Lu Youming,Huang Yuan,Zhang Guo
Caffeine, an antagonist of the adenosine receptor A 1 R, is used as a dietary supplement to reduce body weight, although the underlying mechanism is unclear. Here, we report that adenosine level in the cerebrospinal fluid, and hypothalamic expression of A 1 R, are increased in the diet-induced obesity (DIO) mouse. We find that mice with overexpression of A 1 R in the neurons of paraventricular nucleus (PVN) of the hypothalamus are hyperphagic, have glucose intolerance and high body weight. Central or peripheral administration of caffeine reduces the body weight of DIO mice by the suppression of appetite and increasing of energy expenditure. We also show that caffeine excites oxytocin expressing neurons, and blockade of the action of oxytocin significantly attenuates the effect of caffeine on energy balance. These data suggest that caffeine inhibits A 1 Rs expressed on PVN oxytocin neurons to negatively regulate energy balance in DIO mice.
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JACS Au
·
2024
·
IF 8.5
Gaofei Liu,Jialing Wang,Jianlin Chu,Tianyue Jiang,Song Qin,Zhen Gao,Bingfang He
Nucleoside phosphorylases (NPs) are the key enzymes in the nucleoside metabolism pathway and are widely employed for the synthesis of nucleoside analogs, which are difficult to access via conventional synthetic methods. NPs are generally classified as purine nucleoside phosphorylase (PNP) and pyrimidine or uridine nucleoside phosphorylase (PyNP/UP), based on their substrate preference. Here, based on the evolutionary information on the NP-I family, we adopted an insertions–deletions (InDels) strategy to engineer the substrate promiscuity of nucleoside phosphorylase AmPNPΔS2V102 K, which exhibits both PNP and UP activities from a trimeric PNP (AmPNP) of Aneurinibacillus migulanus. Furthermore, the AmPNPΔS2V102 K exerted phosphorylation activities toward arabinose nucleoside, fluorosyl nucleoside, and dideoxyribose, thereby broadening the unnatural-ribose nucleoside substrate spectrum of AmPNP. Finally, six purine nucleoside analogues were successfully synthesized, using the engineered AmPNPΔS2V102 K instead of the traditional “two-enzymes PNP/UP” approach. These results provide deep insights into the catalytic mechanisms of the PNP and demonstrate the benefits of using the InDels strategy to achieve substrate promiscuity in an enzyme, as well as broadening the substrate spectrum of the enzyme.
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MOLECULES
·
2024
·Vol. 29
·期 19
·4600
·
IF 4.2
Jianfa Wu,Lulu Wang,Ying Cui,Chang Liu,Weixing Ding,Shen Ren,Rui Dong,Jing Zhang
As a traditional Chinese medicine (TCM), Allii Macrostemonis Bulbus (AMB) is a key herb for the treatment of thoracic paralytic cardiac pain, but its quality evaluation method has not yet been fully clarified. In this study, chromatographic fingerprints of AMB were developed using solid-phase extraction–high-performance liquid chromatography–evaporative light scattering detection (SPE-HPLC-ELSD) to evaluate the quality of AMB from various origins and processing methods. This was achieved by employing chemical pattern recognition techniques and verifying the feasibility and applicability of the quality evaluation of AMB through the quantitative analysis of multi-components via a single-marker (QAMS) method. Through the analysis of the fingerprints of 18 batches of AMB, 30 common peaks were screened, and 6 components (adenosine, syringin, macrostemonoside T, macrostemonoside A, macrostemonoside U, and macrostemonoside V) were identified. Moreover, three differential markers (macrostemonoside A, macrostemonoside T, and macrostemonoside U) were screened out using chemometrics techniques, including principal component analysis (PCA), hierarchical cluster analysis (HCA), and orthogonal partial least squares discriminant analysis (OPLS-DA). Subsequently, a QAMS method was established for macrostemonoside T and macrostemonoside U using macrostemonoside A as an internal reference. The results demonstrate the method’s accuracy, reproducibility, and stability, rendering it suitable for the quality evaluation of AMB. This study provides a theoretical basis for drug quality control and the discovery of quality markers for AMB.
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MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Min Zhang,Dandan Guo,Yan Zhu,Shaohua Huang
Inspired by prebiotic reactions derived from wet-cool/dry-hot cycles, a green and efficient dry-wet cycling modification method was proposed for preparing peptide-modified polymer matrices, which are used as mixed-mode stationary phases for HPLC. Using polystyrene-divinylbenzene-glycidyl methacrylate (PS-GMA) as the matrices, alanine monomers were polymerized into peptide on the PS-GMA substrate surface through the dry-wet cycle reaction. By varying the number of dry-wet cycles, the length and density of peptides modified on PS-GMA were easily manipulated. The surface structures of the synthesized stationary phases were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, element analysis, Brunauer-Emmett-Teller test and liquid chromatography-mass spectrometry. Chromatographic separation results demonstrated that the stationary phase after six cycle reactions (PS-GMA-Ala-6C) exhibited the satisfactory selectivity for separating both hydrophilic and hydrophobic analytes. Using PS-GMA-Ala-6C column as the research object, the effects of chromatographic conditions on retention behavior were investigated. The retention mechanisms of the proposed mixed-mode chromatography were deeply analyzed through comparative studies with commercial reversed phase chromatography column, HILIC column and the unmodified PS-GMA column by Tanaka test. Finally, the proposed stationary phase was successfully applied to the qualitative and quantitative analysis of the dihydromyricetin in a real vine tea sample. This work not only presents a green and economically viable method for preparation but also achieves the controllable fabrication of the mixed-mode stationary phase, which is of great significance for the future development of chromatographic stationary phases.
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TALANTA
·
2011
·
IF 3.722
Junxia Hao,Fuqiang Wang,Xiaojun Dai,Bolin Gong,Yinmao Wei
A novel stationary phase for weak cation exchange (WCX) and hydrophilic interaction chromatography (HILIC) was prepared with surface-initiated atom transfer radical polymerization (SI-ATRP). Vinyltetrazole was grafted onto the surface of the beads in water medium with the polyglycidylmethacrylate beads (P GMA/EDMA ) previously modified with 2-bromoisobutryl bromide as the macromolecule initiators and CuCl as catalyst. The poly(vinyltetrazole)-grafted beads obtained with different atom transfer radical polymerization (ATRP) formulations were tried as chromatographic packings in ion-exchange chromatography. The results showed that the prepared columns could separate the tested proteins with high efficiency and high capacity, and the retention time of protein had a positive relationship with increasing the chain lengths of the grafted poly(vinyltetrazole) (PVT). The prepared column was also found to be able to separate nucleosides by hydrophilic interaction chromatographic mode.
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JOURNAL OF CHROMATOGRAPHY A
·
2011
·
IF 4.194
Hongyue Guo,Renhua Liu,Jinjin Yang,Bingcheng Yang,Xinmiao Liang,Changhu Chu
A novel type of zwitterionic HILIC stationary phase was prepared by covalently bonding the l -azido lysine on silica gel via click chemistry. The key intermediate azido lysine was synthesized by transformation the amino group in l -Boc-lysine to corresponding azido group and subsequent removal of the N-protected group (Boc). Finally, the azido lysine was covalently bonded to silica beads by click chemistry to get click lysine. Its structure was confirmed by FT-IR and elemental analysis. The new stationary phase showed good HILIC characteristics, when it was applied to separate polar and hydrophilic compounds, such as organic acids, cephalosporins and carbapenems. Compared with the commercial stationary phases, such as Atlantics HILIC and ZIC-HILIC, click lysine displayed better or similar chromatographic behaviors.
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