高效液相色谱分析七种氟苯甲酸示踪剂

建立了高效液相色谱法测定7种新型水文示踪剂氟苯甲酸的分析方法。使用C18(150 mm,4.6 mmi.d,5μm)色谱柱、乙腈∶水(磷酸盐)=20∶80(2.56 mmol/L)为流动相、紫外检测器,检测波长223 nm。考察了pH、缓冲溶液浓度、有机相浓度等对保留时间的影响。相对标准偏差1.2%~4.2%,线性范围0.05~5.6μg/L。方法的检出限为0.03~0.07μg/L。平均回收率93.3%~106.6%之间。     

高效液相色谱法测定仙草及其加工产品中苯甲酸含量

应用三种不同溶剂对仙草及相关产品中苯甲酸进行提取,结果表明超纯水作为样品中苯甲酸提取溶剂较好;采用高效液相色谱仪、二极管阵列检测器检测对仙草及其加工产品中苯甲酸进行检测,结果表明方法检出限为1.25 mg/kg,样品加标回收率在86~112%间,相对标准偏差在1.53~4.35%间;通过对仙草干草和市场上销售的7个以仙草为主原料的产品进行苯甲酸检测,除一个未检出外,其余均含有一定量苯甲酸。     

反相高效液相色谱法同时测定四种氟喹诺酮类药物

在ＳＨＩＭ－ＰＡＣＫ ＣＬＣ－ＯＤＳ柱上,以甲醇与０．０５ｍｏｌ／Ｌ柠檬酸＋０．０１ｍｏｌ／Ｌ醋酸铵（ＰＨ４．５）（Ｖ甲醇：Ｖ柠檬酸＋醋酸铵＝２５：７５）的混合溶液为流动相,要用反相高效相色谱法分离了测定了四种氟喹诺酮类药物;环丙沙星、氧氟沙星、诺氟沙星、依诺沙星,线必不丙沙星和氧氟沙星１０～１００μｇ／ｍＬ,诺氟沙星和依诺沙星２～８０μｇ／ｍｌ,相关系数ｒ〉０．９９９５,检出限分别为环丙沙星和依     

反相高效液相色谱法测定化妆品中的苯甲酸和山梨酸

建立了反相高效液相色谱法测定化妆品中苯甲酸和山梨酸的分析方法.样品经甲醇超声提取后,直接过滤进样检测.采用Sinochrom C18色谱柱,以0.02 mol/L乙酸铵-甲醇(体积比为85:15)为流动相,流速为2.0 mL/min,检测波长为230 nm.结果表明:苯甲酸和山梨酸浓度在2.00～12.00 μg/mL...     

高效液相色谱法测定化妆品中9种对氨基苯甲酸及其酯类防晒剂

利用反相高效液相色谱法建立了同时测定不同种类化妆品(膏霜、油状、粉饼)中9种对氨基苯甲酸及其酯类防晒剂含量的方法。样品用乙腈进行溶解,超声提取30 min,以Diamonsil C18柱(250 mm×4.6 mm,5μm)为分离色谱柱,甲醇和0.5%(V/V)甲酸水溶液为流动相,梯度洗脱,以311nm为检测波长进行定性,外标法定量。各组分在0.5~1000 mg/L范围内成线性关系,相关系数>0.99,在质量分数为0.1%,1%,5%3个添加水平下平均回收率在85.67%~108.38%,检出限为8~100μg/g。相对标准偏差(n=6)为1.3%~5.1%。     

高效液相色谱法测定铬的三氟乙酰丙酮螯合物

用高效液相色谱分离和检测无机离子的方法已深受色谱工作者的注意,本文研究了以简单的β-二酮-三氟乙酰丙酮作螯合剂,在高效液相色谱仪上测定Cr~(3+)的方法,讨论了Cr~(3+)与三氟乙酰丙酮的给合条件,仪器工作条件选择,以及干扰消除等。建立了测定Cr~(3+)的简单、快速、重现性好的实用方法。     

超高压液相色谱法测定水产品中甲基睾酮的残留量

建立了超高压液相色谱法测定水产品中甲基睾酮残留量的方法。样品采用乙酸乙酯超声波提取,石油醚去脂,乙酸乙酯反萃取,旋转蒸发后用流动相溶解残渣,过滤后上机分析。以V(甲醇):V(水)=60:40为流动相,以C18柱(2.1 mm×100 mm,1.7μm)为色谱分离柱在254nm波长进行测定。方法在5.0~250 ng/mL范围内线性良好(R2=0.9997),在5,30和100μg/kg添加水平下,方法回收率大于91%,相对标准偏差小于7%,定量限为5μg/kg。     

高效液相色谱法同时测定间二甲胺基苯甲酸、间氨基苯甲酸和间硝基苯甲酸

1　引　　言间二甲胺基苯甲酸是重要的染料、医药、农药和有机试剂的中间体 ,尤其是压敏和热敏染料结晶紫内酯的重要中间体之一。随着对结晶紫内酯的需求不断增长 ,国内近几年正在研究开发该产品。本文是伴随以间硝基苯甲酸为原料 ,加氢还原为间氨基苯甲酸 ,再以甲醛甲基化合成间二甲胺基苯甲酸的研究过程的分析测试研究。本方法适用于间二甲胺基苯甲酸产品检测及含有各种中间产物的过程检测。2　实验部分2 .1　仪器和试剂　Ｗａｔｅｒｓ高效液相色谱仪 (包括 5 15泵 ;772 5Ｉ手动进样器 ,2 0 μＬ定量管 ;4 86紫外检测器 ) ,Ａｎａｓｔａｒ…     

高效液相色谱法测定间羟基苯甲酸

用高效液相色谱法测定了间羟基苯甲酸的含量。在反相Ｃ１８柱上,用甲醇－水（ｐＨ２．５）作流动相,紫外２３０ｎｍ检测,以间甲基苯甲酸作内标定量,方法简便、可靠,变异系数为０．２５％～０．３４％。     

高效液相色谱法测定化妆品中对羟基苯甲酸酯类防腐剂

A new methodis described for the simultaneous determination of methyl , ethyl,n-propyl and n-butyl p-hydroxybenzoates(parabens)in cosmetics by HPLC. The method is simple, effective and accurate. After parabens are extracted with ethyl alcohol,the clear ethyl alcohol solution is passed through a neutral alununum oxide column to remove co-extracted lipids and pigments. Parabens are determined by reverse-phase HPLC at 254nm.     

Simultaneous determination of inorganic anions, carboxylic and aromatic carboxylic acids by capillary zone electrophoresis with direct UV detection

Co-electroosmotic capillary zone electrophoresis (CZE) with direct UV detection was developed for simultaneous determination of inorganic anions, carboxylic and aromatic carboxylic acids. These solutes were separated using a 30 mM phosphate buffer containing 1.0 mM tetradecyltrimethylammonium bromide (TTAB) and 20% (v/v) acetonitrile at pH of 6.5 and directly detected by UV at 190 nm. Calibration curves were linear in the range 0.01-2.0 mM, depending of the solutes. The detection limits ranged from 1.0 to 8.0 microM and the relative standards deviations (n=5) in range from 1.9 to 3.6% for the peak area. The proposed method was used to determine inorganic anions and carboxylic and aromatic acids in soil and plant tissue extracts.     

Decarboxylative etherification of aromatic carboxylic acids

Decarboxylative Chan-Evans-Lam-type couplings are presented as a new strategy for the regiospecific construction of diaryl and alkyl aryl ethers starting from easily available aromatic carboxylic acids. They allow converting various aromatic carboxylate salts into the corresponding aryl ethers by reaction with alkyl orthosilicates or aryl borates, under aerobic conditions in the presence of silver carbonate as the decarboxylation catalyst and copper acetate as the cross-coupling catalyst.     

The optimized separation of aromatic carboxylic acids by HPLC

The optimization of the separation of eight aromatic carboxylic acids, using Hypersil SAS and MOS reverse phase columns, with respect to eluent (methanol : water) composition, pH, and temperature, is described. Window diagram techniques are used and the pH of the aqueous buffer and elution temperature are shown to be more critical than eluent composition.     

Gas-liquid chromatography of esters of saturated fluorinated carboxylic acids

GLC has been used to determine the contribution of the methylene and difluoromethylene units to the sorption energy of the members of twelve homologous and pseudohomologous series of esters of n-polyfluorinated carboxylic acids for the SE-30 and SKTFT-50Kh stationary phases at 60–160C. An unusual increase in the energy of sorption of the methylene and difluoromethylene units with the increasing mass of the homolog has been observed. It has been found that, in distinction from the contributions of the methylene units, the sorption energy of the difluoromethylene units in the pseudohomologs is higher on the fluorinecontaining phase SKTFT-50Kh than on the nonpolar SE-30 phase, except the first unit. It has been shown that an increase in the temperature of the analysis reduces the energy contributions but that it has no influence on the general character of change of the sorption energy of the ester homologs and pseudohomologs.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 629–634, March, 1991.     

Cyclization of acetylenic derivatives of aromatic carboxylic acids

The Cu(I)-catalyzed intramolecular cyclization of 1-phenylethynyl-and 1-hexyn-1-yl-anthraquinone-2-carboxylic acid is a 6-endo-dig-addition, whereas the reaction for 1-(3-phenoxypropyn-1-yl)anthraquinone-2-carboxylic acid proceeds in a directionally nonspecific way. It is shown that the cyclization of vicinal acetylenic derivatives of aromatic carboxylic acids leads to the formation of the more stable of the possible cyclic structures.Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk. Novosibirsk State University, 630090 Novosibirsk. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2138–2146, September, 1992.     

Copper-catalyzed aerobic oxidative synthesis of aromatic carboxylic acids

A simple, practical and efficient copper-catalyzed method for synthesis of aromatic carboxylic acids has been developed. The protocol uses inexpensive CuI/L-proline as the catalyst/ligand, and readily available aryl halides and malononitrile as the starting materials, and the corresponding aromatic carboxylic acids were obtained in moderate to good yields. The method is of tolerance towards functional groups in the substrates.     

Direct determination of absolute configuration of carboxylic acids by cyclooctapyrrole

Octaphyrin O1 has been found to be an effective sensor for the direct determination of absolute configuration of a variety of carboxylic acids at mM concentrations at room temperature based on CD exciton chirality method.