JOURNAL OF LIQUID CHROMATOGRAPHY & RELATED TECHNOLOGIES
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2015
·
IF 0.606
Haiyan Liu,Yamin Ma,Fengqing Wang,Jiafei Wang,Quanjie Liu
A new poly(1-dodecene-co-trimethylol propane triacrylate-co-ethylene dimethacrylate) [poly(C12-co-TMPTA-co-EDMA)] monolithic column was prepared via in situ free-radical polymerization reaction. Various parameters affecting the polymerization were investigated and optimized. The permeability of the monolithic column was calculated as 2.9098 × 10−14 m2 with methanol as the mobile phase and the surface areas was 73.1 m2/g by the nitrogen adsorption–desorption experiment. The morphologies of the monolith were characterized by scanning electron microscopy (SEM) and the mechanical strength has been studied in detail as well. The prepared monolith was then used as the stationary phase of reversed phase high-performance liquid chromatography (RP-HPLC) to separate small molecule compounds. Column efficiency for chlorobenzene reached 14,340 theoretical plates per meter. The monolith also showed satisfactory reproducibility, based on the retention times of benzene, phenol, chlorobenzene, diphenylamine, and anthracene; the relative standard deviation (RSD) values for run-to-run, column-to-column and batch-to-batch were less than 0.62%, 3.2%, and 5.7%, respectively.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2016
·Vol. 408
·期 13
·3527-3536
·
IF 3.125
Sun Yanan,Lv Zhengxian,Sun Zhiwei,Wu Chuanxiang,Ji Zhongyin,You Jinmao
A simple, sensitive, and selective high-performance liquid chromatography (HPLC) method using 9-(2-iodoethyl)acridone (IEA) as a novel fluorescence derivatizing agent for the simultaneous determination of six thiophenols has been developed. An efficient Pb 2+ -modified OASIS-MCX cartridge was used and could get good recoveries. IEA was successfully used to label thiophenols with high sensitivity and excellent selectivity. The effects of different solvents, pH, and surfactants on fluorescence properties of derivatives were investigated. To obtain the best labeling efficiency, derivatizing parameters including pH value, temperature, and concentration of IEA, as well as types of catalysts were also evaluated in detail. Under the optimal conditions, the separation could be achieved within 12 min with limits of detection (LODs) in the range of 0.6–5.8 μg L −1 and relative standard deviations (RSDs) < 3.9 %. This is the first time that IEA was applied to the analysis of thiophenols, and the established method has been successfully applied to the trace level detection of thiophenols in industrial wastewater samples.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2017
·
IF 3.255
Xiangyuan Zheng,Lan Luo,Jie Zhou,Xiaoling Ruan,Wenyuan Liu,Feng Zheng
s Acyl chlorides are important acylating agents in the synthesis of active pharmaceutical ingredients. Determining the residual acyl chlorides in drug substances is a challenge due to their high reactivity and the matrix interferences from drug substances and their related impurities. This paper describes a general derivatization HPLC method for the determination of aromatic and aliphatic acyl chlorides in lipophilic drug substances. Since most drug substances have weak absorptions in the visible range (above 380 nm), the nitro-substituted anilines and nitro-substituted phenylhydrazines were selected as the derivatization reagents due to their weak basicity and red-shift of UV absorption spectra. The maximum wavelength and absorption intensity of nitro-substituted anilines decreased after derivatization with acyl chlorides, whereas the derivatization products of nitro-substituted phenylhydrazines showed the slight increases of maximum wavelength and absorbance intensity. Hence, 2-nitrophenylhydrazine was selected as the suitable derivatization reagent because the derivatives have the maximum UV wavelength absorbance at 395 nm, which could largely minimize the matrix interferences. The optimization of the concentration of 2-nitrophenylhydrazine is important for the sensitivity and stability of derivatives. Other reaction conditions including reaction temperature, time and the influence of three competitive solvents (water, methanol and ethanol) on the reaction efficiency were also studied. After derivatization with 100 μg mL −1 2-nitrophenylhydrazine at room temperature for 30 min, the method was validated for high specificity and sensitivity with the detection limits in the range of 0.01–0.03 μg mL −1 . The proposed method was applied as a generic method to determine the residual acyl chlorides in lipophilic drug substances.
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FOOD CHEMISTRY
·
2012
·
IF 3.655
Xiao-Hua Zhang,Hai-Long Wu,Jian-Yao Wang,De-Zhu Tu,Chao Kang,Juan Zhao,Yao Chen,Xiao-Xia Miu,Ru-Qin Yu
This paper describes the use of second-order calibration for development of HPLC-DAD method to quantify nine polyphenols in five kinds of honey samples. The sample treatment procedure was simplified effectively relative to the traditional ways. Baselines drift was also overcome by means of regarding the drift as additional factor(s) as well as the analytes of interest in the mathematical model. The contents of polyphenols obtained by the alternating trilinear decomposition (ATLD) method have been successfully used to distinguish different types of honey. This method shows good linearity ( r > 0.99), rapidity ( t < 7.60 min) and accuracy, which may be extremely promising as an excellent routine strategy for identification and quantification of polyphenols in the complex matrices.
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JOURNAL OF SEPARATION SCIENCE
·
2013
·Vol. 37
·期 5
·587-594
·
IF 2.591
Ting Yang,Chao Ma,Huaixia Chen,Yajie Zhang,Xueping Dang,Jianlin Huang
An IPC-imprinted (IPC is isoprocarb) poly(methacrylic acid)/SiO 2 hybrid monolithic column was prepared and applied for the recognition of the template. The hybrid monolithic column was synthesized in a micropipette tip using methyltrimethoxysilane as the inorganic precursor, 3-(methacryloxy)propyltrimethoxysilane as the coupling agent, and ethylene glycol dimethacrylate as the cross-linker. The synthesis conditions, including the porogenic solvent, coupling agent, volume ratio of the inorganic alcoholysate and organic part, were optimized. The prepared monolithic column was characterized by SEM and FTIR spectroscopy. A simple, rapid, and sensitive method for the determination of IPC in rice using the imprinted monolithic column microextraction combined with HPLC was developed. Several parameters affecting the sample pretreatment were investigated, including the eluent, washing solution, and loading sample volume. The linearity of the calibration curve was observed in the range of 9.0–1000 μg/kg for IPC in rice with the correlation coefficient ( r 2 ) of 0.9983. The LOD was 3.0 μg/kg (S/N = 3). The assay gave recovery values ranging from 91 to 107%. The proposed method has been successfully applied for the selective extraction and sensitive determination of IPC in rice and a satisfactory result was obtained.
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Analytical Methods
·
2013
·Vol. 5
·期 20
·5694-5700
·
IF 1.855
Meng Sun,Ranxiao Tang,Qiuhua Wu,Chun Wang,Zhi Wang
A novel graphene reinforced hollow fiber liquid phase microextraction method was developed for the extraction of phthalates (PAEs) from water, juice and milk samples prior to their determination by high performance liquid chromatography. The main factors that affect the extraction efficiency, such as fiber length, concentration of graphene, extraction time, the pH and ionic strength of the sample solution, and stirring rate were investigated and optimized. Under the optimum conditions, the concentration factors for the analytes ranged between 59 and 71. The limits of detection (S/N = 3) of the method were between 0.2 and 1.2 ng mL−1 for water and juice samples, and between 2.5 and 5.0 ng mL−1 for milk samples. The recoveries of the method were in the range between 81.0% and 108.0% for water, juice and milk samples. The results indicated that the method was rapid, efficient and environmental friendly for the determination of PAEs in different matrix samples.
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Separation Science Plus
·
2024
·Vol. 7
·期 6
·2400021
·
IF 1.3
Duan Yu,Guo Zhongjing,Zhao Zhimin,Yang Depo,Xu xinjun
In this paper, a simple and efficient high-performance liquid chromatography method was established to analyze the chemical composition fingerprint of Centellae Herba (CHA) and determine five triterpenoid active components in CHA, namely, asiaticoside B (AB), madecassoside, asiaticoside, madecasic acid, and asiaticoic acid. The separation of the compounds was carried out on an XD-C18 column (250 mm × 4.6 mm, 5 µm), the wavelength of the ultraviolet detector was set to 205 nm, and the mobile phase was composed of acetonitrile −0.05% phosphoric acid, 2 mmol/L β-cyclodextrin aqueous solution, and gradient elution at the flow rate of 1.0 mL/min. A general chromatographic fingerprint consisting of 20 characteristic peaks of 18 batches of CHA samples was established, and the samples were classified and evaluated by similarity analysis, hierarchical cluster analysis, and principal component analysis combined with multivariate econometric analysis. In quantitative analysis, all calibration curves showed good linear regression in the test range ( r > 0.999), the average recovery was 96.12%–104.63%, and the relative standard deviations of repeatability and stability were less than 2.00%. The results show that the method is accurate and effective and can be used for the comprehensive quality control of CHA.
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JOURNAL OF CHROMATOGRAPHY A
·
2025
·
IF 4
Shu-Yang Sun,Zi- Yu Li,Jia-Hui Zhu,Sheng-Nan Lv,Jie Zhao,Xiao-Shuai Yang,Yu-Shen Liu,Lu-Liang Wang,Wei Chen
Tetracycline antibiotics (TCs) has been widely applied as animal and human medicine for the prevention and treatment of diseases. The unsafe residues of TCs pose serious risks to human health. Development of a rapid and sensitive method for determining TCs residues in environment and food samples is still challenging. Herein, we report the in-situ one-pot self-assembly preparation of core-shell magnetic covalent organic frameworks (Fe 3 O 4 @COFs) composites with crystalline structure for efficient magnetic solid-phase extraction (MSPE) of TCs from various samples. Fe 3 O 4 @COFs showed good enrichment performance for TCs and excellent recyclability. Under optimal MSPE conditions, the developed Fe 3 O 4 @COFs-MSPE-liquid chromatogram method possessed wide linear range (0.80–10000 µg L −1 ), low limits of detection (0.24–0.30 µg L −1 ), low adsorbent consumption (5 mg) and short extraction time (10 min). The extraction mechanism of hydrogen bonding, π-π and hydrophobic interactions was investigated by comparison experiment and adequate analysis and characterizations. This work reveals the potential of crystalline Fe 3 O 4 @COFs composites in sample pretreatment.
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2024
·
IF 4
Wenrui Li,Yike Dang,Ruihong Wang,Weizhong Jin,Xiangli Chen,Yafei Zhai,Zhuoqun Su,Guoliang Li
Fluoroquinolones (FQs) are widely used to treat various animal diseases. The high residue of veterinary drugs in animal-origin food are new pollutants that seriously threaten human health. In this work, Fe 3 O 4 @LDH/ZIF was prepared by the in situ growth of zeolitic imidazolium skeletons (ZIFs) on Fe 3 O 4 @Zn/Al-layered double hydroxides (Fe 3 O 4 @Zn/Al-LDH), which was used as the adsorbent of FQs for magnetic solid phase extraction (MSPE). The prepared materials were characterized by using FT-IR, XRD, TEM, SEM, VSM, zeta, and nitrogen adsorption-desorption analyses. Under the optimized conditions, the limit of detections (LODs) of proposed methods for FQs is determined as low as 0.1–0.6 μg·kg −1 with good linearity (R 2 ≥0.9972). Furthermore, the MSPE approach has been effectively utilized to extract of FQs from a range of meat varieties including fish, pork, chicken, bullfrog, and beef. The recoveries from the spiked samples ranged from 86.5 % to 107 %, with relative standard deviations (RSD) below 8.8 %. These results demonstrated that the prepared nanoparticles hold unique advantages for trace FQs analysis in foodstuffs. This study provides a magnetic adsorbent for food sample pretreatment, which can rapidly enrich compounds similar in structure to fluoroquinolones.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2024
·
IF 3.1
Xinran Zhang,Mohamed Abdulbagi,Limin Wang,Jiafeng Wang,Bin Di,Bo Li
Amino acid epimerization , a process of converting L -amino acids to D -amino acids, will lead to modification in the protein structure and, subsequently, its biological function . This modification causes no change in protein m/z and may be overlooked during protein analysis . Aspartic Acid Epimerization (AAE) is faster than other amino acids and could be accelerated by free radicals and peroxides. In this work, a novel and site-specific HPLC method using a chiral stationary phase for determining the AAE in the active site model peptide (AP) of Peroxiredoxin 2 has been developed and validated. The developed method showed good linearity (1 – 200 μg/mL) and recoveries of the limit of quantification (LOQ), low, medium, and high concentrations were between 85% and 115%. The Kinetics of AAE in AP were studied using the developed method, and the results showed that when ascorbic acid and Cu 2+ coexisted, the AP epimerized rapidly. The AAE extent increased with time and was positively correlated with hydrogen peroxide generation.
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MICROCHIMICA ACTA
·
2011
·Vol. 177
·期 1
·23-30
·
IF 2.578
Wu Qiuhua,Liu Min,Ma Xiaoxing,Wang Weina,Wang Chun,Zang Xiaohuan,Wang Zhi
We have developed a highly sensitive microextraction method for the preconcentration of some phthalate esters such as diethyl phthalate, di- n -propylphthalate, di- n -butyl-phthalate, dicyclohexyl-phthalate, and diethyl-hexyl phthalate prior to their determination by HPLC. It is based on a magnetic graphene nanocomposite as an effective adsorbent. The effects of the amount of the extractant composite employed, extraction time, pH values, salt concentration and desorption conditions were investigated. Under the optimum conditions, the enrichment factors range from 1574 to 2880. Response is linear in the concentration range from 0.1 to 50 ng mL −1 . The limits of detection (at S / N = 3) were between 0.01 and 0.04 ng mL −1 . The method was successfully applied to the determination of five phthalate esters in water and beverage samples.
A novel microextraction method was developed by using magnetic graphene nanocomposite as an effective adsorbent for the preconcentration of some trace phthalate esters in water and beverage samples followed by high performance liquid chromatography with ultraviolet detection. The enrichment factors of the method for the compouds were achieved ranging from 1574 to 2880.
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CHIRALITY
·
2024
·Vol. 36
·期 2
·e23644
·
IF 2.8
Qingli Zeng,Zhiqin Huang,Dan Li,Laisheng Li
A novel bis -triazolyl bridged β-cyclodextrin was first synthesized by the Click reaction between azido-β-cyclodextrin and 1,6-heptadiyne. Then it was bonded onto silica gel to obtain a bis -triazolyl bridged β-cyclodextrin-based chiral stationary phase (BCDP). After structure characterization, the HPLC performance of BCDP was systematically evaluated by using different types of compounds as probes. The results showed that BCDP could well separate 18 kinds of achiral aromatic compounds (homologues, positional isomers, etc.) and 35 kinds of chiral drugs or pesticides, such as triazoles ( R s = 1.33–3.15), flavanones ( R s = 1.49–2.62), dansyl amino acids ( R s = 0.96–1.99), and β-blocker drugs ( R s = 0.68–2.78). BCDP could separate a wider range of compounds (53 kinds); especially, some chiral substance pairs that were difficult to be resolved on the ordinary cyclodextrin CSPs, including triazoles containing two chiral carbons (triadimenol, bitertanol, metconazole, and triticonazole), strongly ionized amino acids (acidic Asp, alkalic Arg, and polar Thr) and β-blockers with bulky groups (carvedilol, propranolol, and pindolol). Obviously, the unique synergistic inclusion effect of bridged cyclodextrin with double cavities and the bis -triazole bridging group could provide multiple action sites, such as hydrogen bonding, π-π stacking and acid–base action sites, thus improving its chiral chromatographic performance.
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