高效液相色谱法快速测定低浓度甜水中的甘油含量

采用高效液相色谱法测定低浓度甜水中甘油的含量,分析条件如下:Zorbax Extend-C18(4.6 mmⅹ250 mm,5μm);柱温35℃;进样量:10μL;差示折光检测器温度:35℃;流速:1.0 mL/min;流动相:纯水。结果表明:甘油出峰的峰形对称性良好,标准曲线有良好的线性关系(R2=0.999 9),实际样品的加样回收率为99.83%~101.59%,方法的相对标准偏差RSD=0.21%(n=6)。     

气相色谱法定量测定牙膏中的薄荷醇、丙二醇和甘油

建立了同时测定牙膏中薄荷醇、丙二醇和甘油含量的气相色谱法。以无水乙醇为溶剂在超声辅助下对8种牙膏样品进行预处理,采用6820型气相色谱仪,配19091X-233 WAX极性毛细管柱(30 m×250μm×0.25μm)进行测定。结果表明,检测的标准偏差为0.17～1.15 mg,平均回收率为89.5%～94.4%。     

The determination of hydrophile-lipophile balance by gas-liquid chromatography

Measurement of the relative retention time of a pair of liquids, one polar and one nonpolar, permits determination of the polarity of the liquid Chromatographic substrate. It is shown that this polarity is a measure of the hydrophile-lipophile balance (HLB) when the substrate is a surface-active agent. The effects of structure, additivity in mixtures, and free polyol are discussed. A GLC apparatus, designed, to permit the rapid determination of HLB by this technique, is described.     

气相色谱法测定氯丙醇含量

氯丙醇是氯醇化生产环氧丙烷的重要中间产物 ,其含量分析一直是采用佛尔哈德化学法 ,由于该方法存在操作复杂、分析时间长及使用对人体有害的硝基苯试剂等缺点 ,因而不适于频繁的中间控制分析。本文介绍一种操作简单、精确度高的方法—气相色谱测定氯丙醇含量。1　化学分析法的基本原理用ＮａＨＣＯ3(固体 )使ＰＣＨ(氯丙醇 )水解 ,水解后的氯离子以铁明矾为指示剂 ,用ＡｇＮＯ3、ＮＨ4 ＳＣＮ标液在酸性条件下滴定 ,求其含量。方程式如下 :ＣＨ3 ＣＨＣｌＣＨ2ＯＨ ＮａＨＣＯ3回流ＣＨ3 ＣＨＯＨＣＨ2ＯＨ ＮａＣｌ 2Ｈ2 ＯＦｅ3 3ＳＣ…     

The determination of small amounts of trimethylene glycol in high gravity and chemically pure glycerine

Summary A method has been developed for the determination of small amounts of trimethylene glycol together with similar constituents in C.P. and high gravity glycerines. The various constituents in known mixtures were determined within 0.2% of the amount present. The method is simple and accurate and utilizes proven A.O.C.S. Methods.     

Quantitative determination of traces of free gossypol in fats,oils, and fatty acids by paper chromatography

Summary A quantitative method for the determination of traces of free gossypol in oils and fatty acids was developed. The method is based on the concentration of gossypol by extraction and quantitative paper chromatography of the extract. The method is specific for free gossypol and is not subject to interferences. The new method is both accurate and reproducible. The lower limit of detection is 10 p.p.m. The method is intended primarily for p.p.m. levels but is suitable for all concentrations. With slight modifications the method is applicable to meals. Presented at the fall meeting of the American Oil Chemists’ Society, Cincinnati, O., September 30 to October 2, 1957.     

The evaluation of crude glycerine

Summary A number of tests applicable to crude glycerine have been studied to find a means of detecting crude glycerines which will cause more difficulty in the refinery or yield a poorer product than would be expected from the results of analyses customarily made. Five tests have been found which are believed to be useful in this way. They are determination of pH, determination of nitrogen, distillation, measurement of the color of the distillate, and measurement of distillate color of stability when heated. It has not been possible to set limits of acceptability for these tests, but a glycerine refiner using one or more of them and correlating laboratory results with experience in the refinery should be able to establish his own standards of quality. Now a division of Arthur D. Little Inc.     

Identification of polyoxyalkylene-type nonionic surfactants by paper chromatography

Despite the increasing importance of nonionic surfactants, methods for their identification have been limited to specific groups. Accordingly, a general analytical scheme for the identification of polyoxyalkylene-type nonionic surfactants was developed, which uses qualitative tests and two paper chromatographic solvent systems. This procedure differentiates among the ethoxylates of alcohols, thioalcohols, alkyl phenol, fatty acids, polyoxyethylene polyoxypropylene acids, sorbitan fatty esters, fatty amides, polyoxyethylene glycols (PEG) condensates. In addition, individual members of a class can be separated and identified. The method is applicable to a variety of detergent products and to mixtures of more than one nonionic. As little as 7 mg of a nonionic surfactant are sufficient for complete characterization. Presented at the AOCS Meeting, Washington, D.C., April, 1968.     

Fractionation of triglyceride mixtures by preparative gas chromatography

A semiautomatic system is described for gas-chromatographic separation and recovery of triglycerides of uniform molecular weight in milligram quantities. It employs an Aerograph Autoprep 700 (Wilkens Instrument and Research Inc.) equipped with a stream splitter and a hydrogen flame ionization detector. The column is an aluminum or stainless steel tube (1/4 in. O.D.×2 ft) and contains silanized Chromosorb W (60–80 mesh) coated with 5% (w/w) JXR or SE-30. Five to ten milligrams of mixed triglyceride are injected at a time and the temperature is programmed exponentially from 150 to 350C. With split ratios of 1∶5 to 1∶10 collections of 20 to 50 mg of each peak can be made with some 10 to 20 injections. Presented in part before the Canadian Committee on Fats and Oils, Ottawa, Ontario, Canada, October 1964.     

Separation of organic mixtures by sequential gas-liquid chromatography

A new sequential continuous chromatographic refiner (SCCR-2) for high temperature production scale G.L.C. (gas-liquid chromatographic) separations is described. In this equipment the counter-current movement between the gas and liquid phase is simulated by sequencing a system of inlet and outlet port functions around twelve static 2.54 cm internal diameter and 61 cm long stainless steel columns. The versatility of the equipment has been demonstrated by the separation of equivolume mixtures of the halocarbons arklone P/genklene P, methylchloroacetate/ethyl lactate and ethyl caprate/ethyl laurate at temperatures of 60°, 105° and 160°C respectively. Throughputs between 21–75 cm³h^?1 have been explored with product purities in excess of 99.8% achieved under certain process conditions.     

The determination of monoglycerides and glycerin in mixtures

A new method of analyzing mixtures containing monoglyceride and glycerin is presented. It is based upon oxidation of the sample with periodic acid. The new method is more rapid than the older methods because it is not necessary to separate the two layers when the glycerin is extracted from the solution of the sample. Precision of the titrations is improved because in the older methods the sample titration must equal at least 80% of the blank titration, but in the new method the sample titration can be very small and a correspondingly greater difference represents the monoglyceride or glycerin in the sample.     

聚醚羟值测定方法的改进

针对聚醚多元醇羟值测定方法中存在的一些问题,对乙酸酐–丙酮法进行了改进,提高其测定稳定性和可靠性,可实现对羟值测定条件的改进和测定环境的改善。通过对水解条件和酰化条件的研究,确定了测定条件,并对此方法的重复性和适用范围进行了考察。实验结果表明:控制不同的取样量,酰化剂中添加定量(乙酸酐质量的15%)对甲苯磺酸,在水浴温度(52±1)℃下酰化回流40 min,水解30 min,用此方法测定聚醚高低不同的羟值,均可保证测定结果有较高的准确度和较好的重复性。     

The determination of fatty amides by high performance liquid chromatography

A high pressure liquid chromatographic technique for separating fatty amides by chain length in the presence of fatty nitriles was developed. The separation used spherical silica with hexane/chloroform/glacial acetic acid (7:2:1, v/v/v) as the mobile phase. The HPLC method can be used to detect trace amounts of fatty amide in the presence of fatty nitrile with a recovery of 99%. Thin layer chromatography was used as a solvent scanning technique. The relationship between k values and R_f values was investigated.     

The determination of vitamin d in margarine by high performance liquid chromatography

Margarine manufactured in South Africa contains vitamin D added at a level of 1-3 international units per gram. Because of the high ratio of lipid to vitamin D, it is difficult to determine the vitamin content for control purposes. A high performance liquid Chro-matographic method for the determination of vitamin D in mar-garine is proposed. The unsaponifiable fraction of a margarine sample is chromatographed twice on an adsorption system. The vitamin D fraction collected from this column is finally injected onto a reverse phase system where vitamins D₂ and D₃ are separated and quantitated with an ultraviolet detector. Vitamin D₂ is used as an internal standard for vitamin D₃ or vice-versa, depending on the form of the vitamin added to margarine. The recovery of 100 ng/g vitamin D₃ added to a margarine mix was 100.1% (coefficient of variation 13.2% for 12 replicates) as calculated from the ratio of peak areas. The detection limit is 1 ng vitamin D. Results for 3 samples of margarine and one sample of butter are given.     

The determination of tissue ethanolamine levels by reverse-phase high-performance liquid chromatography

A rapid and sensitive procedure for the determination of ethanolamine levels in mammalian tissues is reported. Ethanolamine was extracted from the tissue with a chloroform/methanol mixture, followed by phase separation. The aqueous phase was subjected to charcoal chromatography and the lluant was derivatized with phenylisothiocyanate. The amount of phenylthiocarbamyl (PTC) ethanolamine in the tissue extract was determined by reverse-phase high-performance liquid chromatography. Quantitation of PTC ethanolamine was linear between 0.1–10 nmol. The pool sizes of ethanolamine in hamster heart, liver and kidney were found to be 1.07, 0.92 and 1.11 μmol/g wet weight, respectively. The sensitivity of the method would allow the determination of ethanolamine in very small tissue samples.     

离子色谱法测定化妆品中的海藻糖

建立了一种高效阴离子交换-脉冲安培检测(HPAE-PAD)测定化妆品中海藻糖的方法。采用不同的样品前处理方法,用METROSEP CARB 1分离柱(150 mm×4.0 mm)进行分离,以200.0 mmol·L-1的NaOH溶液为流动相进行洗脱,7 min内可完成对样品的分析。结果表明,海藻糖的检出限为0.02 mg·L-1,峰面积的相对标准偏差为0.17%,保留时间的相对标准偏差为0.28%;化妆品中常见的甘油和丙二醇不会对其测定产生干扰,平均回收率为95.2%～99.2%。     

气相色谱法快速测定乙二醇循环气中微量乙醛

采用直接进样填充柱气相色谱法快速测定乙二醇循环气中微量乙醛,对方法的准确度和精密度进行了探讨。方法简便,准确度高,精密度好,回收率83．3％～110．7％,相对标准偏差小于8．9％。     

The determination of hard segments in polyurethane elastomers by high performance liquid chromatography

Summary Reverse phase HPLC methods are elaborated for the characterisation of polyursthane elastomers. The quantitation of urethane groups after aminolysis, as well as the determination of basic hard segments and qualitative hard segments size distribution after hydrolysis in dimethylsulfoxid (DMSO) are described. The methods are ilustrated with diphenylmethane-p,p-bis(4-octanoiloxybutylcarbamate) (U1) as model compound and three different polyurethane formulations.