JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
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2016
·
IF 3.169
Qing Wang,Ling Tong,Lin Yao,Peng Zhang,Li Xu
In the present study, a mixed-mode stationary phase, C18-Diol, was applied for fingerprint analysis of traditional Chinese medicines. Hydrophobic, hydrogen bonding and electrostatic interactions were demonstrated to contribute the retention separately or jointly, which endowed the C18-Diol stationary phase with distinct selectivity compared to the bare C18 one. The separation of total alkaloids extracted from Fritillaria hupehensis was compared on the C18-Diol and conventional C18 column with the greater resolving power and better symmetry responses on the former one. Besides, a novel two-dimensional liquid chromatography on the single column (2D-LC-1C) was realized on C18-Diol with the offline mode for the alcohol extract of Fritillaria hupehensis and online mode for Ligusticum chuanxiong Hort. The early co-eluted extracted components with great polarity on the first dimension were reinjected on the same column and well separated on the second dimension. The results exhibited that the two complementary RPLC and HILIC modes on C18-Diol stationary phase enhanced the separation capacity and revealed more abundant chemical information of the sample, which was a powerful tool in analyzing complex herbal medicines.
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高影响因子
TALANTA
·
2016
·
IF 4.035
Jing Chen,Bao Qiong Li,Min Li Xu,Xue Wang,Yu Hong Jing,Hong Lin Zhai
The interference signals and overlapped peaks are common phenomena in fluorescence determination, which seriously influence the accuracy and reliability of analytical results. In this paper, Krawtchouk image moment method was introduced to the analysis of fluorescence three-dimensional (3D) spectra and applied to the quantitative analysis of three drugs including nicotinic acid, metoprolol and amlodipine in human plasma. Without any pretreatment to the obtained spectra, Krawtchouk moments were directly calculated on the grayscale images of 3D spectra, and the quantitative linear models for the three drugs were established by stepwise regression, respectively. The determination coefficients ( R ) were more than 0.9906. The correlation coefficients of leave-one-out cross-validation ( R cv ) were more than 0.9256. The precisions (RSD, %) of inter-day and intra-day variations were less than 8.4% and 3.1%, separately. The recovery was from 101.84% to 107.88%. The limit of quantification and the limit of detection were 0.12 μg mL −1 and 0.43 μg mL −1 , respectively. All the statistical parameters supported that the obtained models performed well and the proposed method was accurate and reliable. Our study indicates that Krawtchouk image moments with the powerful abilities of multi-resolution and extracting local information can be applied to the simultaneous determination of multi-target compounds in plasma based on fluorescence 3D spectra.
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WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
·
2013
·Vol. 30
·期 1
·245-252
·
IF 1.262
Wang Hualei,Li Guinan,Li Mingyang,Wei Dongzhi,Wang Xuedong
In this study, a novel nitrilase gene from Rhodobacter sphaeroides was cloned and overexpressed in Escherichia coli . The open reading frame of the nitrilase gene includes 969 base pairs, which encodes a putative polypeptide of 322 amino acid residues. The molecular weight of the purified native nitrilase was about 560 kDa determined by size exclusion chromatography. This nitrilase showed one single band on SDS-PAGE with a molecular weight of 40 kDa. This suggested that the native nitrilase consisted of 14 subunits with identical size. The optimal pH and temperature of the purified enzyme were 7.0 and 40 °C, respectively. The kinetic parameters V
max and K
m toward 3-cyanopyridine were 77.5 μmol min −1 mg −1 and 73.1 mmol/l, respectively. The enzyme can easily convert aliphatic nitrile and aromatic nitriles to their corresponding acids. Furthermore, this enzyme demonstrated regioselectivity in hydrolysis of aliphatic dinitriles. This specific characteristic makes this nitrilase have a great potential for commercial production of various cyanocarboxylic acids by hydrolyzing readily available dinitriles.
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高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2013
·Vol. 36
·期 16
·2571-2577
·
IF 2.591
Xi-Tian Peng,Tao Liu,Shu-Xian Ji,Yu-Qi Feng
A novel carboxyl-bonded silica stationary phase was prepared by “thiol-ene” click chemistry. The resultant Thiol-Click-COOH phase was evaluated under hydrophilic interaction liquid chromatography (HILIC) mobile phase conditions. A comparison of the chromatographic performance of Thiol-Click-COOH and pure silica columns was performed according to the retention behaviors of analytes and the charged state of the stationary phases. The results indicated that the newly developed Thiol-Click-COOH column has a higher surface charge and stronger hydrophilicity than the pure silica column. Furthermore, the chromatographic behaviors of five nucleosides on the Thiol-Click-COOH phase were investigated in detail. Finally, a good separation of 13 nucleosides and bases, and four water-soluble vitamins was achieved.
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Analytical Methods
·
2014
·Vol. 7
·期 1
·155-160
·
IF 1.938
Ying Li,Changyin Lv,Qiang Sun,Ying Zhao,Yunjing Li
This study investigated the chromatographic characteristics of irradiated vitamins and their feasibility for dose measurement by using high performance liquid chromatography (HPLC). Water-soluble vitamins in the B family, including thiamine hydrochloride (TH), riboflavin (RF) and nicotinic acid (NA), were used for comparative study. The results showed that riboflavin was sensitive to irradiation, and the content changes of RF were linearly correlated with irradiation doses. Combining the analyses of ultraviolet and fluorescence spectra, the suitable application range for dose determination was confirmed from 100 to 2000 Gy; moreover, the influencing factors were further discussed. The content of RF could maintain good stability before and after irradiation under low-light conditions. These characteristics make it possible for RF to be used as a material for dose measurement. In addition, this work also provides references for irradiation nutrition research due to the favourable separation and analysis characteristics of HPLC.
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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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JOURNAL OF CHROMATOGRAPHY A
·
2015
·
IF 4.169
Qing Wang,Zhi-Yuan Luo,Mao Ye,Yu-Zhuo Wang,Li Xu,Zhi-guo Shi,Lanying Xu
The zirconia-coated silica (ZrO 2 /SiO 2 ) material was obtained by coupling layer-by-layer (LbL) self-assembly method and sol–gel technology, to take dual advantages of the suitable porous structure of SiO 2 and basic resistance of ZrO 2 . Adenosine 5′-monophosphate (5′-AMP) was then self-assembled onto ZrO 2 /SiO 2 via Lewis acid–base interaction, generating 5′-AMP-ZrO 2 /SiO 2 . The chromatographic properties of 5′-AMP-ZrO 2 /SiO 2 were systemically studied by evaluating the effect of acetonitrile content, pH and buffer concentration in the mobile phase. The results demonstrated that the 5′-AMP-ZrO 2 /SiO 2 possessed hydrophilic interaction chromatographic (HILIC) property comprising hydrophilic, hydrogen-bonding, electrostatic and ion-exchange interactions. For basic analytes, the column efficiency of ZrO 2 /SiO 2 and 5′-AMP-ZrO 2 /SiO 2 was superior to the bare ZrO 2 , and different selectivity was obtained after the introduction of 5′-AMP. For acidic analytes, good resolution was obtained on 5′-AMP-ZrO 2 /SiO 2 while the analysis failed on the bare ZrO 2 column owing to strong adsorption. Hence, the proposed 5′-AMP-ZrO 2 /SiO 2 had great potential in analyzing acidic compounds in HILIC mode. It was an extended application of ZrO 2 based SP.
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ELECTRONIC JOURNAL OF BIOTECHNOLOGY
·
2025
·
IF 2.5
Yi Li,Jiacheng Tang,Kaixiang Xin,Zongda Chen,Lele Zhao,Yifan Zhao,Yinbiao Xu,Pei Zhou,Yang Sun,Yupeng Liu,Hua Li
Background Nicotinic acid dehydrogenase possesses the capability to convert nicotinic acid into 6-hydroxynicotinic acid, a compound of significant research value as a pharmaceutical intermediate. The extraction of nicotinic acid dehydrogenase is primarily performed by strains. However, the enzyme activity of the strains reported currently is relatively low, and their potential to catalyze the production of 6-hydroxynicotinic acid is insufficient to meet industrial requirements. Results Due to the revealing properties of 6-hydroxynicotinic acid, this study proposes a technique for calculating the luminescence intensity of colonies, which is based on a fluorescence spectrometer. The developed method establishes a reliable linear relationship (88.2%) between the luminescence intensity and enzyme activity. Consequently, it has been employed to screen strains that produce nicotinate dehydrogenase. This screening approach allows for the evaluation of about 500 enzyme-producing strains daily, presenting an efficient strategy for screening. Conclusions Through this approach, a novel high enzyme activity strain producing nicotinic acid dehydrogenase, Pseudomonas poae have been obtained, which designated as HD530. After process optimization, it was utilized to produce 6-hydroxynicotinic acid, achieving a high yield of 155.45 g/L within 72 h, meeting the requirements for industrial production. The effectiveness and potential of this technique lie in its application for strain screening and improvement.
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Aquaculture Reports
·
2024
·
IF 3.2
Kangyuan Qu,Siyuan Xiong,Caiqian Huang,Xiaoxia Jiang,Lixia Tian,Shiwei Xie
Ornithine is an arginine family amino acid and is not incorporated into protein. This study evaluated its role in growth, immune response and acute NH 3 stress tolerance of Penaeus vannamei . Six diets with graded levels (0.6, 0.9, 1.2, 1.5, 1.8, 2.1 g kg −1 ) of L-ornithine were formulated, and fed the shrimp for 8 weeks. The growth of shrimp was significantly improved with the dietary ornithine levels increased from 0.6 to 1.5 g kg −1 . Feed efficiency, protein efficiency ratio and protein productive value showed a similar trend to the growth performance of shrimp. Whole body protein and muscle lipid of shrimp were significantly increased in shrimp fed 1.8 g kg −1 ornithine compared to those fed 0.6 g kg −1 ornithine. The contents of several amino acids were increased with the dietary ornithine increased to 1.5 g kg −1 . Elevated levels of ornithine increased the Nitric Oxide (NO) content and suppressed arginase activity in the hemolymph. The relative mRNA expression of superoxide dismutase , heat shock protein 70 , dorsal and caspase 3 were increased with the dietary addition of ornithine, while the mRNA level of arginase was decreased with the increasing dietary ornithine levels. After 9 h acute NH 3 stress, mortality of shrimp reduced with the increasing dietary ornithine levels. The relative mRNA levels of superoxide dismutase , heat shock protein 70 , dorsal and catalase were increased with the dietary addition of ornithine after the acute NH 3 stress. The second-order regression analysis of weight gain and survival after acute stress revealed that the suitable ornithine content in the shrimp diet was 1.4–1.5 g kg −1 .
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Zhi Li,Shuangying Li,Liushan Jiang,Jingwen Niu,Yue Zhang,Linchun Nie,Qingxiang Zhou,Chunmao Chen
As a typical kind of new pollutants, there are still some challenges in the rapid detection of antibiotics. In this work, a sensitive fluorescent probe based on boron-doped carbon dots (B-CDs) in combination with thermo-responsive magnetic molecularly imprinted polymers (T-MMIPs) was constructed for the detection of oxytetracycline (OTC) in tea drinks. T-MMIPs were designed, fabricated and employed to enrich OTC at trace level from tea drinks, and B-CDs were utilized as the fluorescent probe to detect the concentration of OTC. The proposed method exhibited good linear relationship with OTC concentration from 0.2 to 60 μg L −1 and the limit of detection was 0.1 μg L −1 . The established method has been successfully validated with tea beverages. Present work was the first attempt application of T-MMIPs in combination with CDs in detection of OTC, and demonstrated that the proposed method endowed the detection of OTC with high selectivity, sensitivity, reliability and wide application prospect, meanwhile offered a new strategy for the method establishment of rapid and sensitive detection of trace antibiotics in food and other matrices.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Detao Li,Zichen Ning,Zhuoshan Gong,Limin Zhou,Li Xu,Feiqiang He,Hamza Shehzad,Heng Jerry,Shichao Du,Jinbo Ouyang
According to in-depth research on cocrystals of polyhydroxylated natural products, we previously summarized the substitution model to elucidate the formation mechanism of cocrystals. However, when refers to salt formation of natural products, the substitution model reveals numerous deficiencies. To compensate for the shortcomings of substitution model in predicting salt formation, this study conducts a comprehensive exploration of natural product salts. By supplementing the energy difference rule to the substitution model, it endows the modified model with broader applicability. Simultaneously, the transfer of protons within salts structures is verified by this modified model. Furthermore, we apply competitive cocrystallization technique to separate flavonoid natural products (quercetin, hesperetin, and naringenin). In view of the characteristics of various natural products as well as their cocrystals/salts, numerous separation processes are developed, and the separation effects of these processes are analyzed in detail. The purity of the products obtained from separation process all reaches above 70%, strongly demonstrating the feasibility of using cocrystallization for the binary separation of flavonoids. This work not only refines the substitution model for predicting cocrystals/salts formation of natural products but also indicates the promising application prospects of cocrystallization in industrial separation of natural products.
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MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Chenyue Kang,Caihong Zhang,Yan Zhang,Guomei Zhang,Shaomin Shuang
Ciprofloxacin (CIP) plays an important role in many physiological processes. Previously reported methods for CIP detection have many drawbacks and so it is crucial to develop highly sensitive methods to detect CIP. In this study, a dual-emission ratiometric fluorescent probe (SF-CQDs/CuAg NCs) of a nanocomposite of carbon quantum dots (SF-CQDs) and copper-silver bimetallic nanoclusters (CuAg NCs) was developed for sensitive and selective detection of CIP. The fluorescent signal of CuAg NCs was quenched while the fluorescence intensity of SF-CQDs was enhanced in the presence of CIP. The working principle of the fluorescent probe SF-CQDs/CuAg NCs is mainly based on the complexation of CIP with CuAg NCs to free SF-CQDs. The quenching of CuAg NCs by CIP arises from the chelation between the metal and the 1-oxo substituent and the adjacent carboxyl group of CIP. The fluorescence recovery of SF-CQDs is attributing to the release of SF-CQDs from SF-CQDs/CuAg NCs and the hydrogen bonding interaction between SF-CQDs and CIP. The ratiometric fluorescence measurement of SF-CQDs/CuAg NCs has been employed to analyze CIP with good sensitivity and selectivity. The working range of CIP is 5.0–200.0 μM and the detection limit is 3.3 μM. More importantly, the fluorescence of SF-CQDs/CuAg NCs can be detected intuitively via a smartphone which can be applied to determine CIP.
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