期刊文献+
共找到863篇文章
< 1 2 44 >
每页显示 20 50 100
Research progress on classification,source,application of phytosterol esters,and their thermal oxidation stability
1
作者 Dami Li Shangde Sun Jingnan Chen 《Grain & Oil Science and Technology》 CAS 2024年第1期1-11,共11页
Phytosterol esters can effectively decrease serum cholesterol concentration in the human body and prevent cardio-cerebrovascular diseases.It was found that phytosterol esters exhibited better solubility and bioavailab... Phytosterol esters can effectively decrease serum cholesterol concentration in the human body and prevent cardio-cerebrovascular diseases.It was found that phytosterol esters exhibited better solubility and bioavailability than free phytosterols.In recent years,phytosterol esters have attracted increasing attention.However,during food processing,phytosterol esters are susceptible to degradation at high temperatures,resulting in certain losses and formation of potentially harmful substances for humans.This paper reviews the relevant literatures and updates on the thermal oxidation stability of phytosterol esters in recent years from the following aspects:(i)Sources,physiological activities,and applications of phytosterol esters;(ii)Oxidation mechanism of phytosterol esters;(iii)Effects of phytosterols species,the volume of addition,food matrix,heating temperature and time,and antioxidants on the thermal loss and oxidation stability of phytosterol esters.The research progress on the safety of phytosterol esters is also discussed in detail.Additionally,the prospects for future research are highlighted. 展开更多
关键词 Thermal stability Loss rate Oxidation mechanism Phytosterol esters
下载PDF
Study on the regulatory effect of liver X receptor in HEK293 cells by six main diterpene esters in Semen Euphorbiae
2
作者 Si-Yuan Ma Fan-Miao Kong +8 位作者 Xiao-Tong Wei Jun-Li Zhang Hai-Ting Zhu Xin-Ning Zhang Yu-Feng Hu Ming-Rui Jiang Hui-Nan Wang Yi-Cen Xu Ying-Zi Wang 《TMR Modern Herbal Medicine》 CAS 2024年第2期35-40,共6页
Background:To study the effects of the main diterpene esters in Euphorbia factor L_(1),L_(2),L_(3),L_(7a),L_(7b)and L_(8)on the transcriptional activity and protein expression of liver X receptor(LXR).Methods:The effe... Background:To study the effects of the main diterpene esters in Euphorbia factor L_(1),L_(2),L_(3),L_(7a),L_(7b)and L_(8)on the transcriptional activity and protein expression of liver X receptor(LXR).Methods:The effect of the main diterpene ester components in Semen Euphorbiae on the viability of HEK293 cells were studied by MTT assay.The LXR-Luc plasmid vector was transfected into HEK293 cells and treated with Euphorbia factor L_(1),L_(2),L_(3),L_(7a),L_(7b)and L_(8)for 24 h.The effect of the main diterpene ester components of Semen Euphorbiae on LXR-Luc luciferase activity was investigated by dual luciferase reporter gene system,and the expression of LXRαprotein was detected by Western Blot.Results:Euphorbia factor L_(1),L_(2),L_(3),L_(7a),L_(7b)and L_(8)could significantly reduce the relative luciferase activity(RLU)of LXRα,and the expression level of LXRαprotein was significantly down-regulated.Conclusion:Euphorbia factor L_(1),L_(2),L_(3),L_(7a),L_(7b)and L_(8)can inhibit the expression of LXR protein level,which may be achieved by inhibiting the transcriptional activity of LXR. 展开更多
关键词 Semen Euphorbiae diterpene esters HEK293 LXR dual luciferase reporter gene system
下载PDF
Recent Advances of Sensitive Electrochemical Sensing Platforms for Rapid Detection of Phthalate Acid Esters
3
作者 Xiuxiu Dong Lili Zhang +2 位作者 Meicai Ge Minfu Wu Qijian Niu 《Instrumentation》 2024年第2期9-23,共15页
As a kind of plasticizer,phthalic acid esters(PAEs)are often added to plastics to enhance elasticity,transparency,durability and prolong service life.However,it does not chemically bind to plastics and is easy to migr... As a kind of plasticizer,phthalic acid esters(PAEs)are often added to plastics to enhance elasticity,transparency,durability and prolong service life.However,it does not chemically bind to plastics and is easy to migrate to the environment.It is difficult to degrade in the environment,and it is also enriched in the human body through the food chain and respiration,which will lead to obvious adverse reactions such as decreased learning and memory function and neurobehavioral disorders.Due to the toxicity,universality and low concentration limitations of PAEs in the environment and food,it is essential to achieve rapid and sensitive detection of PAEs in soil,atmosphere,water and food.Electrochemical(EC)sensors have the advantages of simplicity,fast,low cost,portability,easy operation,high specificity and high sensitivity,so they are applied for the detection of PAEs.Although there are a large number of studies on the detection of PAEs by EC sensors,there is no review on this aspect.In this review,we introduce the detection of PAEs from classical EC sensors,electrochemiluminescence(ECL)sensors and photo-electrochemical(PEC)sensors in the past five years.This review is beneficial to understanding the construction of EC sensors and the detection mechanism of PAEs.We also propose that the development of rapid,accurate and real-time detection methods of PAEs is key to assessing risk and preventing related diseases. 展开更多
关键词 phthalate acid esters electrochemical sensor DETERMINATION
原文传递
Pollution characteristics and risk assessment of organophosphate esters in aquaculture farms and natural water bodies adjacent to the Huanghe River delta
4
作者 Jinyu CHAO Song FENG +2 位作者 Yingdong HAO Jianing LIN Bin ZHANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第1期251-266,共16页
To date,little attention has been paid to the effects of organophosphate esters(OPEs)pollution on aquacultural environment and aquatic product safety.Huanghe(Yellow)River delta area is one of the largest aquaculture c... To date,little attention has been paid to the effects of organophosphate esters(OPEs)pollution on aquacultural environment and aquatic product safety.Huanghe(Yellow)River delta area is one of the largest aquaculture centers in China,where ecological security protection is crucial in the national strategy of China.To explore the pollution characteristics,bioaccumulation,and health risks of OPEs in aquaculture farms in the Huanghe River delta and natural water bodies in the adjacent seas,five species of organisms from different farm types nearby the Huanghe River delta,and the corresponding culture water and sediments were sampled in this study.The total concentrations of Σ_(13)OPEs in water,sediments,and organisms were 51.53-272.18 ng/L,52.63-63.17 ng/g dry weight(dw),and 46.82-108.90 ng/g dw,respectively.Among the five types of culture ponds,the water samples from the swimming crab and hairy crab culture ponds exhibited higher OPEs,the concentration of OPEs in the sediments from the few ponds was relatively balanced,and the OPEs in the organism from the holothurian ponds was higher.Tris(1,3-dichloro-2-isopropyl pho sphate)(TDCP)was the main contaminant in water samples and tripropyl phosphate(TPrP)in sediments and organisms.However,trisphenyl phosphate(TPhP)showed the strongest bioaccumulation ability,followed by 2-ethylhexyl diphenyl phosphate(EHDPP)and TPrP.The bioaccumulation capacities of the five species were as follows:prawn>holothurian>hairy crab>swimming crab>carp.These five types of organisms,as main seafood in human consumption,were at low risk of negative impacts of pollution.However,the risk from the mixture of organophosphate flame retardants(OPFRs)still requires more attention due to the increasing consumption and production in the world. 展开更多
关键词 organophosphate esters(OPEs) aquaculture farms BIOACCUMULATION health risk assessment
下载PDF
Adsorption of Phthalic Acid Esters by Humic Acid and Its Research Progress
5
作者 Ying LI Xiuqin KONG +6 位作者 Dongxia LUO Yinghai LUO Tong CHEN Fengyu WANG Huaxiu XING Fuqiang LI Miantao LEI 《Meteorological and Environmental Research》 CAS 2023年第4期63-66,共4页
Humic acid is rich in highly electronegative oxygen-containing organic functional groups,so it has high reactivity and can adsorb phthalic acid ester(PAEs)in the environment to reduce the risk of environmental polluti... Humic acid is rich in highly electronegative oxygen-containing organic functional groups,so it has high reactivity and can adsorb phthalic acid ester(PAEs)in the environment to reduce the risk of environmental pollution from PAEs.In this paper,the extraction,characterization and adsorption models of humic acid were reviewed,and the research status of adsorption of PAEs by humic acid was further summarized.Based on these,the feasibility and observable application prospect of humic acid as a cheap adsorbent were analyzed. 展开更多
关键词 Humic acid EXTRACTION CHARACTERIZATION Phthalic acid esters ADSORPTION
下载PDF
Anticancer Activities of Substituted Cinnamic Acid Phenethyl Esters on Human Cancer Cell Lines 被引量:4
6
作者 李树春 李辉 +2 位作者 张法 李中军 崔景荣 《Journal of Chinese Pharmaceutical Sciences》 CAS 2003年第4期184-187,共4页
Caffeic acid phenethyl ester (CAPE) and sixteen substituted cinnamic acid phenethyl esters were prepared via conventional procedures in order to test their in vitro anticancer activities by either MTT assay or SRB... Caffeic acid phenethyl ester (CAPE) and sixteen substituted cinnamic acid phenethyl esters were prepared via conventional procedures in order to test their in vitro anticancer activities by either MTT assay or SRB assay on six different human cancer cell lines. The results indicated that in the concentration of 10 μmol·L -1 the lead compound CAPE possessed anticancer activities against human HL 60, Bel 7402, and Hela cell lines, and two other compounds possessed potent anticancer activities against Bel 7402 and Hela cell lines. 展开更多
关键词 medicinal chemistry cinnamic acid phenethyl esters chemical synthesis anticancer activity
下载PDF
Determination of phthalate esters in fat-containing foods by packed nanofiber solid-phase extraction column and gas chromatography 被引量:1
7
作者 邱金丽 王羽 +1 位作者 周小玲 康学军 《Journal of Southeast University(English Edition)》 EI CAS 2016年第3期322-326,共5页
A new method for simultaneous determination of four phthalate esters ( PAEs) in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas... A new method for simultaneous determination of four phthalate esters ( PAEs) in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas chromatography-flame ionization detector ( GC-FID ). Conditions for obtaining optimum extraction efficiency such as extraction solvents, morphologies of adsorbent, ion strength and pH were investigated and optimized in detail. Under the optimized conditions, the limits of detection (LODs) found for dibutyl phthalate (DBP) , butyl benzyl phthalate (BBP), diethyl hexyl phthalate (DEHP) and di-n-octyl phthalate (DNOP) were 50, 25, 50 and 25 ng/g, respectively. Good linearity of four PAEs was achieved in the range of 50 to 4 000 ng/g. The proposed method was applied for analyzing different kinds of fat-containing samples. PAEs in commercial fat-containing samples can be highly extracted by a packed solid-phase extraction column of 5 mg polystyrene ( PS) nanofibers. The satisfactory average recoveries were obtained in the range of 96. 7% to 102. 3% , and the relative standard deviations (RSDs) below 5% were achieved. The proposed method reduces the organic solvent consumption, the complex and tedious procedures for sample pretreatment, and achieves high sensitivity and reproducibility for the investigated PAEs. 展开更多
关键词 phthalate esters (PAEs nanofibers solid-phase extraction gas chromatography fat-containing foods
下载PDF
Insights into biobased epoxidized fatty acid isobutyl esters from biodiesel:Preparation and application as plasticizer
8
作者 Xiaojiang Liang Fengjiao Wu +5 位作者 Qinglong Xie Zhenyu Wu Jinjin Cai Congwen Zheng Junhong Fu Yong Nie 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第4期41-50,共10页
Biodiesel was used to prepare epoxidized fatty acid isobutyl esters(Ep-FABEs)as a biobased plasticizer in this work.Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in ... Biodiesel was used to prepare epoxidized fatty acid isobutyl esters(Ep-FABEs)as a biobased plasticizer in this work.Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in a gas-liquid tower reactor.The conversion achieved nearly 100%within 5 h under the reaction temperature,the mass ratio of catalyst to fatty acid methyl esters(FAMEs),and isobutanol to FAMEs total molar ratio of 180℃,0.4%(mass),and 5.4:1,respectively.In addition,kinetic model of the transesterification reaction was developed at 150–190℃.The calculated activation energy was 48.93 kJ·mol^(-1).Then,the epoxidation of obtained fatty acid isobutyl esters(FABEs)was conducted in the presence of formic acid and hydrogen peroxide.The Ep-FABEs was further analyzed for its plasticizing effectiveness to replace dioctyl phthalate(DOP)and compared with conventional epoxy plasticizer epoxidized fatty acid methyl esters(Ep-FAMEs).The results indicated that the thermal stability and mechanical properties of PVC films with Ep-FABEs plasticizer were significantly improved compared with those plasticized with DOP.In addition,the extraction resistance and migration stability of Ep-FABEs were better than those of EpFAMEs.Overall,the prepared Ep-FABEs via structural modification of biodiesel proved to be a promising biobased plasticizer. 展开更多
关键词 BIODIESEL TRANSESTERIFICATION Isobutyl esters Epoxidized isobutyl esters Biobased plasticizer
下载PDF
Novel Phosphonoacetic Acid Derivatives.Synthesis of N-(Ethoxycarbonylmethylphosphonyl)-α-Amino Esters and-α-Amino Phosphonic Acid Esters and Their Bioactivities
9
作者 Hui Ying LI Kang Tai REN Ru Yu CHEN(Institute of Elemento-Organic Chemistry, Nankai University, Tianjin 300071) 《Chinese Chemical Letters》 SCIE CAS CSCD 1997年第12期0-0,0-0,共4页
A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride ... A series of novel phosphonoacetic acid derivatives, N-(ethoxycarbonylmethy-ethoxyphosphonyl)-α-amino acid esters and α-amino phosphonates, were synthesized via the reaction of the corresponding phosphonyl chloride with amino acid ester hydrochlorides or amino phosphonates in the presence of a base. The preliminary bioassay shows that some compounds show significant anti-viral activity against tobacco mosaic virus (TMV) 展开更多
关键词 Novel Phosphonoacetic Acid Derivatives.Synthesis of N cm PN Amino Phosphonic Acid esters and Their Bioactivities Ethoxycarbonylmethylphosphonyl Amino esters and
下载PDF
New Sesquiterpene Esters from the Culture Filtrate of Calcarisporium arbuscula Isolated from Ganoderma lucidum 被引量:2
10
作者 于能江 郭顺星 肖培根 《Acta Botanica Sinica》 CSCD 2002年第7期878-882,共5页
从四川野生赤芝 (Ganodermalucidum (Leyss.exFr.)Karst.)的一共生菌CalcarisporiumarbusculaPreuss的发酵过滤液中分离得到 3个新的倍半萜酯类化合物 ,分别命名为calcarisporinB2 (1)、B3 (2 )和B4(3) ,通过物理方法和波谱分析确定了... 从四川野生赤芝 (Ganodermalucidum (Leyss.exFr.)Karst.)的一共生菌CalcarisporiumarbusculaPreuss的发酵过滤液中分离得到 3个新的倍半萜酯类化合物 ,分别命名为calcarisporinB2 (1)、B3 (2 )和B4(3) ,通过物理方法和波谱分析确定了它们的结构。 展开更多
关键词 Ganoderma lucidum Calcarisporium arbuscula sesquiterpene esters
下载PDF
Abiotic degradation of four phthalic acid esters in aqueous phase under natural sunlight irradiation 被引量:18
11
作者 Ruttapol Lertsirisopon Satoshi Soda +1 位作者 Kazunari Sei Michihiko Ike 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第3期285-290,共6页
Abiotic degradability of four phthalic acid esters (PAEs) in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunli... Abiotic degradability of four phthalic acid esters (PAEs) in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate (BBP) and di-nbutyl phthalate (DBP), at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate (DEHP) proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di- isononyl phthalate (DINP) catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life (t1/2) obtained in the experiments, the abiotic degradability of the PAEs was in the sequence: DINP (32-140 d) 〉 DBP (50-360 d), BBP (58-480 d) 〉 DEHP (390-1600 d) under sunlight irradiation (via photolysis plus hydrolysis). Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition. 展开更多
关键词 phthalic acid esters abiotic degradation PHOTOLYSIS HYDROLYSIS first-order kinetics
下载PDF
Cloud point extraction coupled with HPLC-UV for the determination of phthalate esters in environmental water samples 被引量:24
12
作者 WANG Ling JIANG Gui-bin +3 位作者 CAI Ya-qi HE Bin WANG Ya-wei SHEN Da-zhong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第7期874-878,共5页
A method based on cloud point extraction was developed to determine phthalate esters including di-ethyl-phthalate (DEP), di- (2-ethylhexyl)-phthalate (DEHP) and di-cyclohexyl-phthalate (DCP) in environmental w... A method based on cloud point extraction was developed to determine phthalate esters including di-ethyl-phthalate (DEP), di- (2-ethylhexyl)-phthalate (DEHP) and di-cyclohexyl-phthalate (DCP) in environmental water samples using high-performance liquid chromatography separation and ultraviolet detection (HPLC-UV). The non-ionic surfactant Triton X-114 was chosen as extraction solvent. The parameters affecting extraction efficiency, such as concentrations of Triton X-114 and Na2SO4, equilibration temperature, equilibration time and centrifugation time were evaluated and optimized. Under the optimum conditions, the method can achieve preconcentration factors of 35, 88, 111 and detection of limits of 2.0, 3.8, 1.0 ng/ml for DEP, DEHP and DCP in 10-ml water sample, respectively. The proposed method was successfully applied to the determination of trace amount of phathalate esters in effluent water of the wastewater treatment plant and the lixivium of plastic fragments. 展开更多
关键词 phthalate esters cloud point extraction Triton X-114 non-ionic surfactant HPLC-UV
下载PDF
Epoxidation of Unsaturated Fatty Acid Methyl Esters in the Presence of SO_3H-functional Brφnsted Acidic Ionic Liquid as Catalyst 被引量:15
13
作者 蔡双飞 王利生 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2011年第1期57-63,共7页
The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (I... The epoxidation of unsaturated fatty acid methyl esters(FAMEs)by peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid was studied in the presence of SO3H-functional Brnsted acidic ionic liquid (IL)[C3SO3HMIM][HSO4]as catalyst.The effects of hydrogen peroxide/ethylenic unsaturation ratio,acetic acid concentration,IL concentration,recycling of the IL catalyst,and temperature on the conversion to oxirane were studied.The kinetics and thermodynamics of unsaturated FAMEs epoxidation and the kinetics of oxirane cleavage of the epoxidized FAMEs by acetic acid were also studied.The conversion of ethylenic unsaturation group to oxirane, the reaction rate of the conversion to oxirane,and the rate of hydrolysis(oxirane cleavage)were higher by using the IL catalyst. 展开更多
关键词 in situ epoxidation kinetics oxirane cleavage unsaturated fatty acid methyl esters Brnsted acidic ionic liquids
下载PDF
Highly efficient synthesis of β-amino esters via Mannich-type reaction under solvent-free conditions using ZnCl_2 catalyst 被引量:8
14
作者 Albert S.C.Chan 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第4期407-410,共4页
β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid de... β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid derivatives. 展开更多
关键词 β-Amino esters Aspartic acid derivativates Mannich-type reaction SOLVENT-FREE Krapcho decarboxylation reaction Zinc chloride
下载PDF
Toxic effects of several phthalate esters on the embryos and larvae of abalone Haliotis diversicolor supertexta 被引量:5
15
作者 杨志会 张祥景 蔡中华 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第2期395-399,共5页
As the most widely used plasticizers in the world, phthalate esters (PAEs) are potential endocrine disruption compounds (EDCs). In the present study, the toxicity of dimethyl phthalate (DMP), diethyl phthalate ... As the most widely used plasticizers in the world, phthalate esters (PAEs) are potential endocrine disruption compounds (EDCs). In the present study, the toxicity of dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di (2-ethylhexyl) phthalate (DEHP) on embryogenesis and larvae development of the marine univalve Haliotis diversicolor supertexta was examined in laboratory. The results show that the malformation of embryos appeared during the experiment, such as embryos died or lysed, small transparent flocculent rings studded on the periphery of the embryo, and the larvae could failed to hatch. In embryo toxic test, embryos incubated at the highest concentration of DMR DEP and DBP solutions showed significantly high abnormal rate compared with the control, while DEHP solutions displayed no significant difference. In larval toxic test, in all concentrations of DMP, DEP and DBP solutions, larval settlement rates were low significantly than that of the control. Similarly, DEHP solutions show nearly no effect on the larval settlement. The order of toxicity on embryos and larvae is DBP〉DEP〉DMP〉DEHE Being a simple and easy stimulation to indoor spawn, sensitive to environmental factors, and short culture time, the embryos of H. diversicolor supertexta can be used to indicate toxicity of the PAEs. 展开更多
关键词 Haliotis diversicolor supertexta phthalate esters embryos LARVAE TOXICITY
原文传递
Determination of astaxanthin and astaxanthin esters in shrimp shell by HPLC 被引量:8
16
作者 LI Shuai GUO Jun-ru +6 位作者 FENG Jin-hua ZHU Ze-min LI Ling-li GUO Xiao-fang SUI Wen-yan WANG Meng ZUO Wen-ting 《Marine Science Bulletin》 CAS 2019年第2期57-71,共15页
A method for determination of astaxanthin and astaxanthin eaters in shrimp shell by high performance liquid chromatography is established.Shrimp shell are addressed with 5%hydrochloric acid to remove calcium ions.Afte... A method for determination of astaxanthin and astaxanthin eaters in shrimp shell by high performance liquid chromatography is established.Shrimp shell are addressed with 5%hydrochloric acid to remove calcium ions.After shell is dried,organics from shrimp shell are extracted with anhydrous ethanol.The alcohol extrative of the shrimp shell is mixed with the ammonium sulfate to extract astaxanthin by aqueous two-phase extraction.The crude astaxanthin is collected,which is distributed in the middle layer of the aqueous two-phase layer.After distilled water is added to the crude astaxanthin,the aqueous solution is centrifuged,and the previous step is repeated for several times.The precipitation in centrifuge tube is collected and dried.The crude astaxanthin dried is dissolved with acetone,and the sample solution is separated by TLC.Every pigment on the TLC plate is collected and dissolved with acetone.The pigments are determined by high performance liquid chromatograph.The results show that aqueous two-phase system,3 mL alcohol extractive of astaxanthin and 4.5 mL 20%ammonium sulfate,can be used to acquire crude astaxanthin.The wavelength of the maximum peak of astaxanthin in ethanol solution is 472 nm.A variety of pigments can be separated from the crude astaxanthin by thin-layer chromatography,including free astaxanthin,astaxanthin monoester,astaxanthin diester,echinenone and other substances.It can be seen from high performance liquid chromatography that the appearance time of free astaxanthin is from 4 min to 5.5 min,and the appearance time of astaxanthin monoester is from 10.5 min to 27.8 min.The method is simple about the sample pretreatment and feasible about the determination of astaxanthin and astaxanthin esters in shrimp shell. 展开更多
关键词 ASTAXANTHIN astaxanthin esters aqueous two-phase thin-layer chromatography high performance liquid chromatography
下载PDF
Analysis of Phthalate Esters in Air, Soil and Plants in Plastic Film Greenhouse 被引量:6
17
作者 Xi Kui WANG Wei Lin GUO +1 位作者 Ping Rui MENG Jia An GAN 《Chinese Chemical Letters》 SCIE CAS CSCD 2002年第6期557-560,共4页
The phthalate esters such as DMP, DEP, DBP and DEHP in air, soil and plant samples in plastic film greenhouse were clean up with fine silica gel column and determined with HPLC. It was found that the concentrations o... The phthalate esters such as DMP, DEP, DBP and DEHP in air, soil and plant samples in plastic film greenhouse were clean up with fine silica gel column and determined with HPLC. It was found that the concentrations of PEs in air and soil samples in plastic film greenhouse are much higher than those of contrast samples. But concentrations of PEs in plants in plastic film greenhouse are not remarkably affected by the pollution of air and soil. 展开更多
关键词 Phthalate esters plastic film greenhouse analysis.
下载PDF
Analysis of Sucrose Esters with Long Acyl Chain by Coupling of HPLC-ELSD with ESI-MS System 被引量:5
18
作者 朱金丽 汤艳峰 +1 位作者 李建华 张淑芬 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第6期1032-1037,共6页
The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection (HPLC-ELSD) and electrospray ionization mass spectrum (ESI... The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection (HPLC-ELSD) and electrospray ionization mass spectrum (ESI-MS) is investigated. The improved HPLC-ELSD method for the separation and quantitation of commercial and synthesized sucrose esters is described. Samples are analyzed by means of a reversed-phase (RP) HPLC using a Hypersil C8 column (250 mm× 4.6 mm, 5 μm particle size) with methanol-tetrahydrofuran (vo)ume ratio of 90 : 10) and water under gradientcondition as the mobile phase, in which the flow rate is 1.0 ml·min^-1 and the column temperature is set at 40℃. This procedure provides a complete separation and determination ot monoester, diester, triester and higher esters with different acyl chain lengths in each fraction by a single run, in combination with the ESI-MS technology. With this method, it is possible to determine the approximate compositions of monoto polyesters in one analysis and quantitate pure positional isomers precisely using an external standard method. It is found that the method of ESI-MS coupling with HPLC system for the analysis of sucrose esters is straight forward, rapid and inexpensive, and can be readily applied in synthesis, purification and structure studies. 展开更多
关键词 sucrose esters long acyl chain ANALYSIS high performance liquid chromatographic method with evaporative light scattering detection electrospray ionization mass spectrum
下载PDF
The setereoselective preparation ofβ-keto esters using baker's yeast in the presence of rice wine koji 被引量:4
19
作者 Jin Cui Ming Jie Zhang Xiang Qian Wang Nai Jing Cui 《Chinese Chemical Letters》 SCIE CAS CSCD 2008年第3期311-313,共3页
By the addition of rice wine koji, enhancement of the reactivity was observed for the baker's yeast reduction of β-keto esters into (S)-β-hydroxy esters with high enantiomeric purity (73-98%).
关键词 Baker's yeast BIOCATALYST Rice wine koji β-Keto esters
下载PDF
Study on the Quantitative Structure-toxicity Relationships for the Selected Esters by Using Molecular Electronegativity Interaction Vector (MEIV) 被引量:4
20
作者 李建凤 廖立敏 王碧 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2011年第9期1225-1232,共8页
The molecular electronegativity interaction vector (MEIV) was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression (MLR) and p... The molecular electronegativity interaction vector (MEIV) was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression (MLR) and partial least-squares regression (PLS). The correlation coefficients (R) of the two models were 0.945 and 0.941, respectively. The models were evaluated by performing the cross validation with the leave-one-out (LOO) procedure. The cross-verification correlation coefficients (RCV) of the two models were 0.921 and 0.919, respectively. The results showed that the models constructed in this work could provide estimation stability and favorable predictive ability. 展开更多
关键词 esters tetrahymena pyriformis half-inhibitory growth concentration (IGC50) structural characterization quantitative structure toxicity relationship (QSTR)
下载PDF
上一页 1 2 44 下一页 到第
使用帮助 返回顶部