分散液相微萃取-高效液相色谱法同时测定尿样中多环芳烃四种代谢产物

本研究建立了同时测定尿样中多环芳烃的四种代谢产物1-羟基芘、萘、1-萘酚和2-萘酚的分散液相微萃取-高效液相色谱法。确定了最佳的色谱条件,并对萃取剂种类及用量、分散剂种类及用量、萃取时间、加盐量、样品pH和挥干时间等条件进行了优化。在最佳的实验条件下,建立了四种组分的工作曲线,线性相关系数均达到0.9999,线性范围可达103,检出限(S/N=3)为0.06～0.3ng/mL,样品加标平均回收率为95.4%～105%,相对标准偏差为2.4%～3.5%。     

分散液相微萃取-气相色谱法测定水样中六种芳香胺

建立了分散液相微萃取-气相色谱同时测定环境水样中氟苯胺等6种芳香胺的方法.确定了色谱条件,在4 min内实现了对6种芳香胺的分离与测定;对萃取剂种类及用量、分散剂种类及用量;水样pH值、NaCl加入量等前处理条件进行了优化,使得水样中6种芳香胺得到了同时提取和富集.在最佳实验条件下,建立了6种物质的工作曲线,其相关系数...     

HPLC法同时测定尿样中芳香族化合物的6种代谢产物

建立了同时测定尿样中反,反-粘康酸、马尿酸、苯乙醇酸、苯乙醛酸、对氨基酚和对硝基酚的高效液相色谱法(HPLC).优化了色谱分离及检测条件,并采用时间程序波长检测.确定了最佳样品预处理条件:以5 mL二氯甲烷-异丙醇(7∶3)为萃取溶剂;样品用量5 mL;NaCI加入量0.75 g;萃取时间2 min,分别在酸性和中性条...     

分散液相微萃取/高效液相色谱法同时测定啤酒中3种酮类老化物质

建立了分散液相微萃取(DLLME)/高效液相色谱(HPLC)同时测定啤酒中双乙酰、2,3-戊二酮和β-大马酮3种主要酮类老化物质的方法.确定了双乙酰和2,3-戊二酮的衍生化反应条件和3种目标组分同时检测的高效液相色谱条件,在15 min内实现了对3种酮类老化物质的分离和检测;优化了分徽液相徽萃取的实验条件,使3种目标组...     

中空纤维三相液相微萃取-高效液相色谱法测定水中的4种酚类化合物

建立了中空纤维液-液-液三相微萃取-高效液相色谱法测定水中4种酚类化合物的方法.实验系统地优化了影响萃取效率的因素(包括有机溶剂种类、接收相浓度、分散相pH值、加盐量、转速及萃取时间).得到的最佳萃取条件为:萃取剂为正辛醇,接收相NaOH溶液的浓度为0.09 mol/L,分散相的pH为4,萃取时间为40 min,搅拌速...     

分散液液微萃取-气相色谱法测定水样中甲基环硅氧烷

将分散液液微萃取与气相色谱法技术相结合,建立了测定水样中3种甲基环硅氧烷残留的方法.重点探讨了萃取剂的种类和用量、分散剂的种类和用量、萃取时间及盐浓度等对样品萃取效率的影响.结果表明在优化条件下,待测物在5～100μg/L范围内线性良好(r＞0.99),检出限在2～4μg/L之间,富集倍数可达165～170倍,相对标准...     

人尿液中麻黄碱和可待因的液-液-液微萃取/高效液相色谱法测定

建立了液-液-液微萃取与高效液相色谱联用技术快速分析尿样中麻黄碱和可待因的方法.优化得到的最佳萃取条件:萃取溶剂为80μL苯,接受相为1.0μL 0.2 mol·L-1的HCI,搅拌速率为80 r·min-1,萃取时间为40 min.在该条件下.获得了高的富集因子(大于117倍).方法的线性范围为麻黄碱0.05-10mg·L-1,可待因0.10-10 mg·L-1,相关系数(r)大于0.997,检出限分别为0.025 mg·L-1和0.05 mg·L-1,相对标准偏差小于9%.该方法能有效地去除尿样中的干扰物质,有机溶剂消耗少,萃取效率高,可同时测定尿样中麻黄碱和可待因.     

分散液-液微萃取结合HPLC测定富马酸替诺福韦酯中9-丙烯基腺嘌呤

将分散液-液微萃取与HPLC结合,建立了测定富马酸替诺福韦酯中的基因毒性杂质9-丙烯基腺嘌呤的分析方法。同时对影响萃取效率的各项参数如萃取剂的种类及用量、分散剂的种类及用量、溶液体系pH、离子强度及萃取时间等进行了优化。将样品用水溶解,调节溶液至pH 9. 0,NaCl浓度为3 g/L,以300μL正庚醇为萃取剂,萃取时间为3 min,3000 r/min离心3 min,取上层进行液相分析。结果表明,9-丙烯基腺嘌呤在1. 22～366 ng/mL范围内线性关系良好,检测限为0. 41 ng/mL,平均回收率为96. 2%～97. 8%,RSD 1. 0%。方法满足富马酸替诺福韦酯中基因毒性杂质9-丙烯基腺嘌呤的测定要求。     

离子液体-分散液液微萃取-比色法测定水样中痕量铁

建立了基于分散液液微萃取(DLLME)-数字成像比色(DIC)法测定水样中Fe的方法。在乙酸-乙酸钠缓冲溶液中,Fe(Ⅲ)被盐酸羟胺还原成Fe(Ⅱ)后与邻菲罗啉作用生成橙红色络合物。以离子液体[C6M IM][PF6]为萃取剂,乙腈为分散剂,采用涡旋辅助的分散液液微萃取方法对该络合物进行萃取和富集后,直接通过手机比色装置对Fe进行测定。优化了手机比色装置参数和分散液液微萃取的萃取剂种类及用量、分散剂种类及用量等条件。结果表明,在最佳条件下,方法的线性范围为24～200μg/L,相关系数(r~2)为0.9973,检出限为3μg/L,加标回收率为90.0%～108.0%,相对标准偏差(RSD)为0.8%～1.8%。该方法可用于测定环境水样中痕量Fe。     

液-液-液三相液相微萃取-高效液相色谱法检测尿样中的安非他明和氯胺酮

建立了液-液-液三相液相微萃取与高效液相色谱联用技术测定尿样中的安非他明和氯胺酮的方法。考察了萃取溶剂、料液相pH值、搅拌速度、萃取时间和接受相HCl浓度等因素对富集因子的影响,得到了萃取溶剂为300 μL甲苯,料液相pH值为11,接受相为1.0 μL 0.1 mol/L HCl,搅拌速度为600 r/min,萃取时间为50 min的最佳实验条件。在该条件下,获得了较高的富集因子;方法的线性范围为安非他明0.01～10 μg/mL,氯胺酮0.01～5 μg/mL,相对标准偏差均小于2%,检测限均为5 ng/mL (S/N=3)。建立的三相液相微萃取方法能有效地去除复杂基体的干扰,有机溶剂消耗少,萃取效率高,是一种有效、灵敏的样品前处理方法,适合于尿样中安非他明和氯胺酮的测定。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Synthesis of tetrabenzoporphins of the basis of isoindoline

Chemistry of Heterocyclic Compounds -