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…     

硫酸氢钠催化合成苯甲酸酯

以—水硫酸氢钠催化苯甲酸和各种醇合成了一系列的苯甲酸酯。反应条件为：苯甲酸50mmol，n(苯甲酸)：n(醇)：n(硫酸氢钠)=1：3(或4)：0．2，反应时间2h。部分产物经元素分析，IR和1H NMR表征。     

气相色谱法测定医用苯甲酸软膏中的苯甲酸与水杨酸含量

复方苯甲酸水杨酸制剂或软膏被广泛用作外用杀菌或消毒药.近年报导的测定方法主要有薄层法[1],卡尔曼滤波分光光度法[2]与气相色谱分析法[3].用气相色谱法测定苯甲酸或水杨酸等芳香酸或取代芳香酸,多将这些酸先经各种衍生反应转变为相应的酯再进行气相色谱测定[4,5].所采用的酯化衍生反应有些较为繁琐,有些反应不够完全或引入了某些衍生试剂,给分离系统或GC分离带来一些不利影响.本文提出了一种新的丁酯衍生化前处理法.用本法测定医用苯甲酸软膏中的苯甲酸与水杨酸含量,先以75%的热乙醇溶液充分溶解软膏基质,之后用冰水骤冷使基质从乙醇溶液中析出,然后将溶液中的待测酸转变为相应丁酯并选择102硅烷化白色载体涂渍5%的SE-30填充柱对各酸丁酯进行GC分离.本法定量准确,操作也较简便.     

硝基苯甲酸与氨基苯甲酸六种异构体的HPLC分离研究

采用Kromasil C18(4.6×200mm)柱同时分离了硝基苯甲酸与氨基苯甲酸六种异构体,在不到7min的时间内,硝基苯甲酸与氨基苯甲酸异构体在0.1～1.0g/L 浓度范围内,得到了良好分离.     

氯化铁催化合成苯甲酸异丁酯

用氯化铁水合物催化苯甲酸与异丁醇的酯化反应，探讨了氯化铁催化合成苯甲酸异丁酯的反应条件。     

褶合光谱法测定复方苯甲酸醇溶液中的苯甲酸和水杨酸

利用褶合光谱法不经分离同时测定复方苯甲酸醇溶液中苯甲酸和水杨酸的含量，苯甲酸和水杨酸的平均回收率分别为100.15%、100.02%，测定结果的相对标准偏差分别为1.40%、0.58%。     

毛细管电泳在拮抗药物对氨基苯甲酸，对羟基苯甲酸和磺胺分析测…

本报道了一种用毛细管区带电泳法分离与测定对氨基苯甲酸、对羟基苯甲酸及磺胺类药物的新方法。电泳条件为：用２０ｍｍｏｌ／Ｌ硼砂－２０ｍｍｏｌ／ＬＨ３ＰＯ４－２０ｍｍｏｌ／Ｌβ－环糊精－４％乙醇作电泳液，Ｌ－抗坏血酸为内标，２８０ｎｍ为检测波长，样品由电进样方式１０ｋＶ／１０ｓ）引入毛细管（５１．２ｃｍ×５０μｍｉ．ｄ．，有效分离长度为３８．５ｃｍ）．在２４．５℃下，６ｍｉｎ内三可达基线分离（电泳电     

对氨基苯甲酸的合成研究进展

综述了以对硝基苯甲酸为原料合成对氨基苯甲酸的近期研究进展。并从技术和经济角度讨论了各种合成方法的优点与不足。     

高纯苯甲酸的重量滴定分析

用重量滴定法结合电位滴定二阶导数法确定终点,对二级量热标准苯甲酸作纯度测定,结果为９９．９７％,测定精度达０．０１５％。     

反相高效液相色谱法同时测定3—羟基苯甲酸及3,5—二羟基苯甲酸的含量

１引言３，５．二羟基苯甲酸（１）及３－羟基苯甲酸（２）是合成咳喘素类药物的重要原料，它们本身的合成都是采用苯甲酸为原料，经磺化、碱熔得到。为了提高（１）、（２）的纯度，通常需严格控制合成工艺条件。但难免（１）中伴随着（２），（２）中伴随着（１）。对于含量的测定，通常是采用酸碱滴定法，但此时测得的是（１）、（２）的总量，无法确定它们各自的纯度。为此，我们研究了（１）、（２）在ＲＰ－ＨＰＭ上分离检测的最佳适宜条件，经１０余种流动相及不同流量的试验，结果表明：用乙睛－缓冲溶液（每升含７ｇ磷酸二氢钾，０…     

Determination of resin acid composition in rosin samples using cyclodextrin‐modified capillary electrophoresis

Rosins are used in a wide variety of industries in varnishes, adhesives, drug coatings, etc. In this project a novel capillary electrophoresis method was developed to investigate the resin acid composition of rosins. The acids were separated and the concentrations of individual acids present in gum rosin samples determined in order to investigate any links between the presence and concentration of these acids and the tendency of rosins to crystallize. The capillary electrophoresis method successfully separated nine resin acids in various rosin samples where previously they could not all be separated. Calibration curves were created to determine acid concentration. Abietic, dehydroabietic, neoabietic, pimaric, isopimaric, levopimaric, sandaracopimaric, palustric, and 7‐oxo‐dehydroabietic acids were separated using a 20 mM tris buffer at pH 9 containing 15% methanol 5 mM (2‐hydroxypropyl)‐γ‐cyclodextrin 10 mM sulfobutylether‐β‐cyclodextrin. Their concentrations in a crystallizing and a noncrystallizing rosin sample were determined.     

A novel synthesis of amino acid derivatives of phospholene oxides

A convenient synthetic approach is established to prepare a new class of 1-l-α-amino acid derivatives of phospholene oxides by amination of (±)-1-chloro-2-phospholene-1-oxides with several optically pure l-α-amino acid esters. All compounds obtained as a diastereomeric mixture in good to high yields. The two diastereomers were successfully separated by column chromatography and structurally identified by their spectral analyses.     

Determination of poly(ethylene glycol) 300 in long chain free fatty acid mixtures by reversed-phase high-performance liquid chromatography

A rapid sensitive method has been developed for the detection and quantitation of poly(ethylene glycol) 300 (PEG 300) in long-chain free fatty acid mixtures that requires minimal sample preparation. The PEG 300 was separated from the free fatty acids by RP-HPLC using a water–tetrahydrofuran gradient. PEG and the free fatty acids were detected using evaporative light scattering detection. The minimum detectable level of PEG in a free fatty acid mixture was 0.0125%.     

Separation and identification of lichen acids of the pulvinic acid series

Lichen acids, pulvinic acid, vulpinic acid, pinastric acid, leprapinic acid, lsoplnastric acid and pulvinic acid dilactone, which occur in certain yellow varieties of lichens and are difficult to separate, have been successfully separated and identified by TLC on chlorobenzene-impregnated silica gel plates.     

Proximate composition,amino acid and fatty acid composition of fish maws

Fish maws are commonly recommended and consumed in Asia over many centuries because it is believed to have some traditional medical properties. This study highlights and provides new information on the proximate composition, amino acid and fatty acid composition of fish maws of Cynoscion acoupa, Congresox talabonoides and Sciades proops. The results indicated that fish maws were excellent protein sources and low in fat content. The proteins in fish maws were rich in functional amino acids (FAAs) and the ratio of FAAs and total amino acids in fish maws ranged from 0.68 to 0.69. Among species, croaker C. acoupa contained the most polyunsaturated fatty acids, arachidonic acid, docosahexaenoic acid and eicosapntemacnioc acid, showing the lowest value of index of atherogenicity and index of thrombogenicity, showing the highest value of hypocholesterolemic/hypercholesterolemic ratio, which is the most desirable.     

Micropacked capillary nucleic acid analysis

Nucleic acid compositional analysis is discussed, followed by a brief review of the current state of the technology applied in which the benefits and limitations of current methodology are enumerated. An alternative method is presented, namely the use of a micropacked capillary ion exchange column to separate nucleoside monophosphates via an anion exchange mechanism. The separated nucleotides are then quantitated by means of post-column photodiode-array detection. The use of a photodiode array also enables the verification of peak identity and purity by acquisition of UV spectra at any point in the separation. The technique has applications in the compositional analysis of both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).     

高效液相色谱法同时测定生物质乳酸发酵液中有机酸及糖类化合物

建立了高效液相色谱(HPLC)同时测定生物质乳酸发酵液中有机酸及糖类的分析方法。使用Bio-Rad Aminex HPX-87H色谱柱,以5 mmol/L的H2SO4为流动相,在柱温55 ℃,流速0.6 mL/min条件下,采用示差折光检测器进行检测。结果表明,该方法可在17 min内实现发酵液中各种有机酸和糖类化合物等的完全分离与定量,6种有机酸和3种糖类化合物在0.15～5.19 g/L范围内的线性关系良好,回归方程的线性相关系数在0.9998以上。将该法用于米根霉发酵液的检测,两个水平的加标回收率为96.91%～103.11%,相对标准偏差(n=6)为0.81%～4.61%。该法适用于微生物发酵液中多种有机酸和糖类的快速、高效分离和定量测定。     

Analysis of methylphosphonic acid, ethyl methylphosphonic acid and isopropyl methylphosphonic acid at low microgram per liter levels in groundwater

A method is described for determining methylphosphonic acid, ethyl methylphosphonic acid and isopropyl methylphosphonic acid, which are hydrolysis products of the nerve agents VX (S-2-diisopropylaminoethyl O-ethyl methylphosphonothiolate) and GB (sarin, isopropylmethyl phosphonofluoridate). The analytes are extracted from 50 ml groundwater using a solid-phase extraction column packed with 500 mg of silica with a bonded quaternary amine phase, and are eluted and derivatized with methanolic trimethylphenylammonium hydroxide. Separation and quantitation are achieved using a capillary column gas chromatograph equipped with a flame photometric detector operated in its phosphorus-selective mode. Two independent statistically-unbiased procedures were employed to determine the detection limits, which ranged between 3 and 9 μg/l, for the three analytes.     

Highly efficient heterogeneous acylations of aromatic compounds with acid anhydrides and carboxylic acids by montmorillonite-enwrapped titanium as a solid acid catalyst

Montmorillonite-enwrapped titanium hydroxide species (Ti⁴⁺-mont) acted as a highly efficient heterogeneous acid catalyst for the acylation of aromatic compounds with acid anhydrides or carboxylic acids. The catalytic activity of the Ti⁴⁺-mont was higher than those of other acid catalysts such as zeolites, SO ₄ ²⁻ /ZrO₂ and p-toluenesulfonic acid. For example, the reaction of anisole with dodecanoic acid in the presence of the Ti⁴⁺-mont catalyst gave 1-(4-methoxyphenyl)-1-dodecanone in 97% yield. Furthermore, the Ti⁴⁺-mont catalyst was easily separated from the reaction mixture and was recyclable.     

Separation of triacylglycerols and free fatty acids in microalgal lipids by solid-phase extraction for separate fatty acid profiling analysis by gas chromatography

Microalgal lipids were separated into two fractions, triacylglycerols (TAGs) and free fatty acids (FFAs), by solid-phase extraction employing sodium carbonate as the sorbent and dichloromethane (20% by volume) in n-hexane as the extracting solvent. The TAG fraction was then saponified, followed by acidification, extraction and tert-butyldimethylsilyl esterification. The FFA fraction was directly acidified, extracted and derivatized. From the lipid extracts of eight microalgal species examined, a total of 13 fatty acids were detected in the TAG fractions and nine were found in the FFA fractions, with at much higher total TAG content in all microalgae. Oleic acid was the most prominent fatty acid in three species, α-linolenic acid was more abundant in two others, and palmitic acid was present in highest concentration in the remaining three species.