CHINESE JOURNAL OF CHEMISTRY
·
2013
·Vol. 31
·期 3
·371-376
·
IF 0.917
Wei Zhu,Haoyang Wang,Haihui Peng,Guosheng Liu,Yinlong Guo
Pd-catalyzed oxidative coupling reaction was of great importance in the aromatic C H activation and the formation of new C O and C C bonds. Sanford has pioneered practical, directed C H activation reactions employing Pd(OAc) 2 as catalyst since 2004. However, until now, the speculated reactive Pd(IV) transient intermediates in these reactions have not been isolated or directly detected from reaction solution. Electrospray ionization tandem mass spectrometry (ESI-MS/MS) was used to intercept and characterize the reactive Pd(IV) transient intermediates in the solutions of Pd(OAc) 2 -catalyzed oxidative coupling reactions. In this study, the Pd(IV) transient intermediates were detected from the solution of Pd(OAc) 2 -catalyzed oxidative coupling reactions by ESI-MS and the MS/MS of the intercepted Pd(IV) transient intermediate in reaction system was the same with the synthesized authentic Pd(IV) complex. Our ESI-MS(/MS) studies confirmed the presence of Pd(IV) reaction transient intermediates. Most interestingly, the MS/MS of Pd(IV) transient intermediates showed the reductive elimination reactivity to Pd(II) complexes with new C O bond formation into product in gas phase, which was consistent with the proposed reactivity of the Pd(IV) transient intermediates in solution.
研究领域:
有机化学
·
金属有机化学
·
分析化学
·
催化化学
·
质谱学
✓ 已验证
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2014
·
IF 3.583
Shengling Sun,Jie Li
A method has been developed for the determination of zirconium (Zr), hafnium (Hf), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), and tin (Sn) in seawater by quadrupole inductively coupled plasma-mass spectrometry (Q-ICP-MS). The method is based on separation of the seven elements by extraction chromatography using N-benzoyl-N-phenylhydroxylamine (BPHA) supported on a microporous acrylic ester polymeric resin. The optimized procedure indicates that the BPHA resin has high selective adsorption for Zr, Nb, Mo, Sn, Hf, Ta, and W (known as fluoride soluble elements), whereas other interference and matrix elements are minimally adsorbed. The optimized eluent mixture with their molarity gives satisfactory recoveries for all analytes. The recovery can be achieved 99% for Zr, 97% for Nb, 97% for Mo, 99% for Sn, 99% for Hf, 95% for Ta, and 98% for W, respectively, by eluting with 6 mL of 6 mol L − 1 HF/1 mol L − 1 HCl. Furthermore, the technique for separation and enrichment of these elements provides a low total method blank. The detection limits for this method are 0.5 ppt for Zr, 0.2 ppt for Nb, 1.7 ppt for Mo, 1.0 ppt for Sn, 0.1 ppt for Hf, 0.1 ppt for Ta, and 0.3 ppt for W, respectively. The validity of the method is evaluated by replicate analyses of seawater reference materials; the precision of the results is better than 3% (RSD, n = 4), and the results are in good agreement with certified values. The established procedure has proved to be both practical and effective for seawater sample analyses.
研究领域:
分析化学
·
海洋化学
·
环境地球化学
·
痕量元素检测
·
质谱分析
✓ 已验证
DOI
高影响因子
SOLID STATE IONICS
·
2022
·
IF 3.699
Tayfun Kocak,Xiadong Qi,Xiaogang Zhang
The extended cyclability of LiNi 0.5 Mn 1.5 O 4 (LNMO) electrodes featuring different water-based binders is here reported. LNMO electrodes with guar gum (GG) binders show a relatively stable cycle performance at 0 °C and room temperature. However, water-based binders exhibit higher capacity fade than those with polyvinylidene fluoride (PVdF) binder at 50 °C. Although PVdF binder has a lower adhesion force than CMC and GG; PVdF-based electrodes exhibit better capacity retention than those with water-based binders at 50 °C over 1000 cycles. Finally, operando Differential Electrochemical Mass Spectrometry (DEMS) experiments were carried out to analyze the evolution of volatile decomposition products formed over cycling at 1C and 30 °C of CMC-, GG- and PVdF-based LNMO electrodes. CO 2 and H 2 gas evolutions increase remarkably at both high temperatures and high potentials, i.e., ~ 4.7 V.
研究领域:
电化学
·
材料科学
·
能源存储
·
锂离子电池
·
电极材料
✓ 已验证
DOI
高影响因子
FOOD AND AGRICULTURAL IMMUNOLOGY
·
2019
·
IF 2.398
Lipeng Yuan,Bo Liu,Kaidan Yin,Zhen-Lin Xu
In this study, a heterologous competitive indirect enzyme-linked immunosorbent assay (ciELISA) for the determination of estriol (E3) in milk was developed. Rabbit polyclonal antibody specific for E3 was raised by introducing a carboxyl spacer arm from bromoacetic acid of E3 as immunizing hapten. A heterologous ciELISA using a coating hapten containing a carboxyl spacer arm from 6-ketoestriol of E3. The assay exhibited the required sensitivity for detection of E3 with limit of detection of 0.07 ng mL−1 and a working range from 0.41 ng mL−1 to 15.78 ng mL−1. Good recoveries were obtained ranging from 83.2% to 125.8% for E3 spiked milk samples. A satisfactory correlation (R2 = 0.994) between the results of ciELISA analysis and that of LC–MS/MS analysis indicated good accuracy and reproducibility of the proposed method, which was ideally suited as a rapid screening tool for routine E3 monitoring.
研究领域:
生物化学
·
分析化学
·
食品科学
✓ 已验证
产品关联
DOI
高影响因子
TheScientificWorldJOURNAL
·
2014
·Vol. 2014
·期 1
·162465
·
IF 1.219
Haiying Luo,Yanping Xian,Xindong Guo,Donghui Luo,Yuluan Wu,Yujing Lu,Bao Yang
A new technique was established to identify eight organophosphate esters (OPEs) in this work. It utilised dispersive liquid-liquid microextraction in combination with ultrahigh performance liquid chromatography/tandem mass spectrometry. The type and volume of extraction solvents, dispersion agent, and amount of NaCl were optimized. The target analytes were detected in the range of 1.0–200 µ g/L with correlation coefficients ranging from 0.9982 to 0.9998, and the detection limits of the analytes were ranged from 0.02 to 0.07 µ g/L ( S / N = 3). The feasibility of this method was demonstrated by identifying OPEs in aqueous samples that exhibited spiked recoveries, which ranged between 48.7% and 58.3% for triethyl phosphate (TEP) as well as between 85.9% and 113% for the other OPEs. The precision was ranged from 3.2% to 9.3% ( n = 6), and the interprecision was ranged from 2.6% to 12.3% ( n = 5). Only 2 of the 12 selected samples were tested to be positive for OPEs, and the total concentrations of OPEs in them were 1.1 and 1.6 µ g/L, respectively. This method was confirmed to be simple, fast, and accurate for identifying OPEs in aqueous samples.
研究领域:
环境分析化学
·
污染生态学
·
毒物代谢
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水质安全
·
持久性有机污染物
✓ 已验证
DOI
高影响因子
Asian Journal of Pharmaceutical Sciences
·
2016
·Vol. 12
·期 2
·202-208
·
IF 0
Huiyan Shi,Chenzhi Hou,Liqiang Gu,Zhe Wei,Hang Xing,Meiyu Zhang,Shixiao Wang,Longshan Zhao,Kaishun Bi,Xiaohui Chen
The present study was designed to investigate the influence of the pretreatment of piperazine ferulate on pharmacokinetic parameters of methotrexate in methotrexate-induced renal injury rats. A simple and efficient high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) method was developed to determine methotrexate in rat plasma. Methotrexate and syringic acid (internal standard) were extracted from rat plasma samples by protein precipitation with acetonitrile. The analysis was performed on a CAPCELL PAK C 18 column (150 mm × 4.6 mm, 5 µm) with acetonitrile and 5 mmol/l ammonium acetate aqueous (10:90, v/v ). The linear range was 5.0 × 10 −2 to 100.0 µg/ml for methotrexate. Other parameters were all within the acceptance criteria. The validated method was successfully applied the pharmacokinetic study of methotrexate between two methotrexate treated groups (with and without the pretreatment of piperazine ferulate). Compared with the methotrexate treated alone group, the pharmacokinetic parameters in the methotrexate with the pretreatment of piperazine ferulate group showed significantly lower MRT (0-t) , MRT (0-∞) and T 1/2 . Results suggested that methotrexate can be rapidly eliminated, cleared or metabolized in rat blood, which might be related to the pretreatment of piperazine ferulate. The method provided deeper insights into rational clinical use of methotrexate with the pretreatment of piperazine ferulate on cancer patients with renal dysfunction.
研究领域:
药理学
·
药物代谢
·
肾脏病学
·
肿瘤学
·
临床药学
·
分析化学
✓ 已验证
DOI
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2013
·
IF 2.947
Chen Li,Feng Xu,Chen Cao,Ming-Ying Shang,Cui-Ying Zhang,Jie Yu,Guang-Xue Liu,Xuan Wang,Shao-Qing Cai
Traditional Chinese medicines (TCM) can be identified by experts according to their odors. However, the identification of these medicines is subjective and requires long-term experience. In this paper, electronic nose, headspace gas chromatography–mass spectrometry (GC–MS) and chemometrics methods were applied to differentiate two species of Asari Radix et Rhizoma by their odors. The samples used were the dried roots and rhizomes of Asarum heterotropoides var. mandshuricum (AH) and Asarum sieboldii (AS). The electronic nose was used to determine the odors of the samples and enabled rapid differentiation of AH and AS when coupled with principal component analysis. Headspace GC–MS was utilized to reveal the differences between the volatile constituents of AH and AS. In all, 54 volatile constituents were identified, and 9 major constituents (eucalyptol, eucarvone, 3,5-dimethoxytoluene, 3,4,5-trimethoxytoluene, methyleugenol, 2,3,5-trimethoxytoluene, croweacin, pentadecane and asaricin) could be used as chemical markers to distinguish these two species. AH contained higher relative contents of eucarvone (1.79–16.76%), 3,5-dimethoxytoluene (6.64–26.52%), 3,4,5-trimethoxytoluene/methyleugenol (6.43–31.67%) and 2,3,5-trimethoxytoluene (1.64–6.66%), whereas AS had higher relative contents of eucalyptol (14.06–24.95%), croweacin (5.64–13.55%), pentadecane (8.44–20.82%) and asaricin (7.03–13.45%). Moreover, AH and AS could be distinguished according to the contents of either all 54 identified volatile constituents or only the 9 major constituents by employing cluster analysis. The proposed method is rapid, simple, eco-friendly and can successfully differentiate these two species of Asari Radix et Rhizoma by their odors.
研究领域:
中药鉴定
·
分析化学
·
天然药物化学
·
代谢组学
·
药用植物学
✓ 已验证
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2017
·
IF 4.95
Li Wang,Li-Fang Liu,Jian-Ying Wang,Zi-Qi Shi,Wen-Qi Chang,Meng-Lu Chen,Ying-Hao Yin,Yan Jiang,Hui-Jun Li,Ping Li,Zhong-Ping Yao,Gui-Zhong Xin
In this study, a new strategy combining mass spectrometric (MS) techniques with partial least squares regression (PLSR) was proposed to identify and quantify closely related adulterant herbal materials . This strategy involved preparation of adulterated samples, data acquisition and establishment of PLSR model. The approach was accurate, sensitive, durable and universal, and validation of the model was done by detecting the presence of Fritillaria Ussuriensis Bulbus in the adulteration of the bulbs of Fritillaria unibracteata. Herein, three different MS techniques, namely wooden-tip electrospray ionization mass spectrometry (wooden-tip ESI/MS), ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) and UPLC-triple quadrupole tandem mass spectrometry (UPLC-TQ/MS), were applied to obtain MS profiles for establishing PLSR models. All three models afforded good linearity and good accuracy of prediction, with correlation coefficient of prediction ( r p 2 ) of 0.9072, 0.9922 and 0.9904, respectively, and root mean square error of prediction (RMSEP) of 0.1004, 0.0290 and 0.0323, respectively. Thus, this strategy is very promising in tracking the supply chain of herb-based pharmaceutical industry , especially for identifying adulteration of medicinal materials from their closely related herbal species.
研究领域:
药物分析
·
中药质量控制
·
代谢组学
·
分析化学
·
天然药物化学
·
药物鉴定
·
食品与药品安全
✓ 已验证
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Zhanshi Ni,Haobo Bi,Chunlong Jiang,Hao Sun,Wenliang Zhou,Zhicong Qiu,Qizhao Lin
Faced with increasingly severe environmental and energy issues, the development and utilization of solid waste have become a trend. In this study, a thermogravimetric-Fourier infrared spectrometer-mass spectrometer (TG-FTIR-MS) was used to carry out the co-pyrolysis experiment of coal slime and cellulose. The samples with mass mixing ratios of 0:10, 1:9, 3:7, 5:5, 7:3, 9:1, and 10:0 were pyrolyzed in N 2 atmosphere. The percentages of mass loss during the pyrolysis of coal slime and cellulose were 15.69 and 94.28%, respectively. The addition of cellulose to the coal slime could significantly improve the pyrolysis performance of the sample. It was detected by FTIR that the pyrolysis of the blends mainly formed C=O-containing compounds. MS was used to monitor the ion current intensity of gaseous products of sample pyrolysis online. The average activation energy of the reaction between coal slime and cellulose calculated by the Kissinger-Akahira-Sunose method were 237.59 kJ/mol and 174.06 kJ/mol, respectively. The principal component 1 and principal component 2 dominated the co-pyrolysis process of coal slime and cellulose. The MAE, RMSE, and R 2 of the artificial neural network prediction model for predicting the pyrolysis process of the sample were 0.5249, 0.8244, and 0.9994, respectively. This research provided basic theory and data support for understanding the co-pyrolysis of coal slime and biomass.
研究领域:
能源化学
·
环境科学
·
热化学转化
·
可再生能源
·
固体废物利用
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2020
·
IF 3.905
Yanshuxian Liu,Yilei Fan,Zhongping Huang,Huijun Liu,Lili Wang,Zhenlu Shen,Ichi Watanabe
A novel method based on on-line pyrolytic methylation-gas chromatography/mass spectrometry was established and applied into rapid determination of γ-hydroxybutyric acid (GHB) in human hair. With the pyrolytic methylation by tetramethylammonium hydroxide (TMAH), GHB was converted into its corresponding methyl ester in the pyrolyzer at 500 °C. Thus, GHB in hair samples could be well determined by GC/MS on a capillary column in SIM mode. To obtain optimum methylation conditions, important factors were investigated and then applied to the following experiments. The results were obtained as following: 500 °C as reaction temperature, 2:1 as the proportion of TMAH to GHB. The achieved calibration curve exhibited good linearity with the correlation coefficient of 0.9997 at the concentraion range of 2−200 ng/mg, and relative standard deviation (n = 3) from 1.3 %–7.7 %. The limit of detection and the limit of quantification were down to 0.3 ng/mg and 1.0 ng/mg, respectively. The precision ranged from 2.0 %–7.9 % and the recovery ranged from 98.5 %–107.4 %. The results of on-line pyrolytic methylation-GC/MS were in agreement with those observed by the referenced off-line silylation-GC/MS method. The method was applied to a real case of a woman addicted to GHB, the drug concentration in hair segments of 0−5 cm and 5−10 cm from the root strand well correlated with the use of GHB in different periods of her life. The proposed method demonstrated significant potential in the application of rapid determination for GHB in human hair.
研究领域:
法医毒理学
·
药物代谢
·
分析化学
·
生物样本分析
·
临床化学
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2024
·
IF 5.8
Hong Wang,Bingzhi Liu,Qiang Xu,Shijun Dong,Zhandong Wang,Long Zhu
Cyclopentanone (CPN) is a widely available biofuel with excellent combustion properties, but detailed speciation profiles during its pyrolysis have rarely been studied. This work examines the pyrolysis of CPN in a jet-stirred reactor (JSR) at atmospheric pressure, with residence time of 2 s and a temperature range from 830 K to 1100 K. Dozens of pyrolysis intermediates and products were measured using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) and gas chromatography (GC). Among them, several new species were observed, including water, carbon dioxide , formaldehyde, indene , 1,2-dihydroindene, naphthalene , 1,2-dihydronaphthalene, 1-methylnaphthalene, acenaphthylene , biphenyl , and fluorene . A detailed kinetic model was developed based on the literature, and in general, it predicted the experimental results for most species well. Kinetic analyses indicated that the consumption of CPN was controlled by the bimolecular reactions with H atom. The formation of water, carbon dioxide and formaldehyde could be explained by the reaction pathways of OH radical. The pyrolysis of CPN yielded a significant number of alkenes and alkynes at higher temperatures; the bimolecular addition reactions of these species with resonantly stabilized radicals are important to the formation of polycyclic aromatic hydrocarbons (PAHs). Based on those, this work provides valuable insights into CPN pyrolysis chemistry and it promotes the development of a comprehensive CPN combustion model.
研究领域:
燃烧化学
·
能源化学
·
反应动力学
·
分析化学
·
环境化学
✓ 已验证
DOI
高影响因子
Biomed Research International
·
2017
·Vol. 2017
·期 1
·2564363
·
IF 2.476
Zuoyi Yang,Junhui Zhou,Yanbin Xu,Yaping Zhang,Haien Luo,KenLin Chang,Yujie Wang
Indole and its derivatives are typical nitrogen heterocyclic compounds and have been of immense concern since they are known for the risk of their toxic, recalcitrant, and carcinogenic properties for human and ecological environment. In this study, a Gram-negative bacterial strain of eliminating indole was isolated from a coking wastewater. The strain was confirmed as Acinetobacter pittii L1 based on the physiological and biochemical characterization and 16S ribosomal DNA (rDNA) gene sequence homology. 400 mg/L indole could be completely removed within 48 h by the strain on the optimum condition of 37°C, pH 7.4, and 150 rpm. The organic nitrogen was converted to NH 3 -N and then to and the organic carbon was partially transferred to CO 2 during the indole biodegradation. The metabolic pathways were proposed to explain the indole degradation based on the liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis of indigo, 4-(3-Hydroxy-1H-pyrrol-2-yl)-2-oxo-but-3-enoic acid, and isatin. The toxicity of the biodegradation products was evaluated using the Microtox test, which revealed that the metabolites were more toxic than indole. Our research holds promise for the potential application of Acinetobacter pittii L1 for NHCs degradation, production of indigoids, and soil remediation as well as treatment of indole containing wastewater.
研究领域:
环境微生物学
·
生物降解
·
分析化学
·
环境毒理学
·
废水生物处理
·
分子生物学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）