Separation and purification of lecithins by high pressure liquid chromatography

Ten different synthetic lecithins have been analyzed by reverse-phase high pressure liquid chromatography. An empirical lecithin “carbon number” that depends on the total number of carbons and double bonds in the fatty acyl chains in a useful index in predicting retention volumes of lecithins on a nonpolar octadecyl fatty acid column. Commercial egg lecithin is separated into its components by this technique.     

The purification of fatty acid methyl esters by high pressure liquid chromatography

Procedures are described for the rapid purification of gram quantities of methyl oleate, methyl linoleate, methyl α- and γ-linolenates and methyl ricinoleate from appropriate natural oils by high pressure liquid chromatography (HPLC).     

Isolation and purification of carbazole contained in anthracene slag by extraction combined with medium pressure liquid chromatography

Ultrasonic-assisted extraction (UAE) combined with medium pressure liquid chromatography (MPLC) was designed for carbazole separation from anthracene slag (AS). The effects of liquid/solid ratio, temperature, and extraction times on carbazole separation were investigated. When using CCl₄ and ethyl acetate as extraction solvents and combining with MPLC, carbazole recovery and purity are 75.1% and 95.4%, respectively. The mechanism for carbazole separation were presumed by examining intermolecular interactions such as N-H…π, π-π, and C-Cl…π interactions. These results demonstrate that UAE/MPLC has a considerable potential as a green and promising strategy for separating and purifying carbazole and other chemicals from AS.     

Purification of phospholipids by preparative high pressure liquid chromatography

A method is described for the purification of a number of phospholipids by preparative high performance liquid chromatography (HPLC). Purification of digalactosyl-diglyceride from spinach and egg phosphatidylcholine, 1,2-dioleoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine from its reaction mixture have been resolved. The lipid separation is performed on a polygosil column and the individual compounds are monitored directly by refractive index detection. Chloroform/methanol mixtures are used as eluent systems, providing a wide polarity range to separate the classes of lipids. The developed equipment can be used for columns between 10 and 50 cm long and 4 and 50 mm inner diameter. The flow rate could be varied between 1 and 100 ml/min and applied pressures between 10 and 450 bars.     

阻燃剂磷酸双酚A四苯酯（BAPP）的液相色谱分析

用高效液相色谱法（HPLC）分离阻燃剂磷酸双酚A四苯酯,液-质谱联用定性分析,面积归一化法定量。采用Spheri SorbC18／SiO2（粒径5μm,规格250mm×4．6mm）为色谱柱,以乙腈／四氢呋喃／0．04％磷酸水溶液（三者体积比为35：30：35）为流动相,流速0．8mL／min,乙腈的吸收波长为210nm,四氢呋喃吸收波长为280nm,样品BAPP分别在270nm、254nm波长下有两个吸收峰,通过对乙腈、四氢呋喃、BAPP紫外光谱的分析,选择测定波长254nm。该分析方法可以作为BAPP纯度的分析方法来表征所合成的产品质量,虽然双酚A组分相对偏差较大,基本能够满足控制分析方法的需要。     

Jojoba oil analysis by high pressure liquid chromatography and gas chromatography/mass spectrometry

Two analytical procedures for determining com-positions of jojoba liquid wax esters are described and compared. One, the more tedious, involves separation of wax ester homologs by high pressure liquid chro-matography followed by determination of the acid and alcohol moieties from each homolog. The second allows rapid determination of wax ester composition by gas Chromatographic separation of hydrogenated jojoba wax esters according to chain length, followed immediately by ancillary mass spectrometric identifi-cation of the acid and alcohol moieties. Double bonds in the alkyl chains in jojoba liquid waxes were almost exclusively (98%) ω-9, when examined by gas chro-matography/mass spectrometry (GC/MS) and ozonolysis/GC/MS. Presented in part at the 2nd International Conference on Jojoba and Its Uses, Ensenada, Mexico, February, 1976.     

Analysis of dolichol in human tissues by high pressure liquid chromatography

Dolichol from human liver was shown by reverse-phase high pressure liquid chromatography to consist of a series of homologues ranging in length from 17 to 23 isoprene units. The two major components, corresponding to 19 and 20 isoprene units, respectively, were isolated and identified by mass spectrometry. Dolichyl palmitate, synthesized from liver dolichol, showed an identical series of peaks with longer retention times. Attemps to chromatograph dolichyl phosphate under similar conditions were unsuccessful. Dolichol from uterine tissue and several other human tissues showed a shift toward shorter chain length, with a predominance of homologues containing 18 and 19 isoprene units.     

Separation ofCis andTrans isomers by reverse phase high pressure liquid chromatography

A reverse phase high pressure liquid chromatography procedure was devised for the analytical or preparative separation of geometric isomers of dodecenyl acetates, tetradecenyl acetates, hexadecenyl acetates, tridecadienyl acetates, and methyl oleate and elaidate. Use of μ Bondapak C-18 permitted the separation of these isomers. ARS, USDA.     

Separation of oxidized and unoxidized molecular species of phosphatidylcholine by high pressure liquid chromatography

Soy phosphatidylcholine (PC) has been separated into its major molecular species by reversephase high pressure liquid chromatography (HPLC). An aqueous methanol gradient was used that allowed detection of the various species by their absorbance at 206 nm. Oxidized species were detected by their absorbance at 234 nm and were resolved from the unoxidized species. This technique has been used to separate and purify unoxidized dilinoleyl phosphatidylcholine (di 18∶2 PC) from other species of soy PC and to monitor the autoxidation of an aqueous suspension of the purified di 18∶2 PC. Two oxidized products were formed from di 18∶2 PC. Further analysis showed that they were PC, but one of the products contained an oxidized and an unoxidized fatty acid; in the other product, both fatty acids were oxidized. Present in part at FASEB 63rd Annual Meeting, Dallas, Texas, April 1979.     

Analysis of trichlorocarbanilide and triclosan in soaps by reverse phase high pressure liquid chromatography

A method has been developed for the rapid and direct analysis of bacteriostats (3,4,4′-trichlorocarbanilide and 2,4,4′-trichIoro-2′ -hydroxydiphenyl ether) in soaps with the aid of reverse phase high pressure liquid chromatography (HPLC) The bacteriostats were conveniently analyzed by UV absorption detection at 280 nm. A typical analysis of bacteriostats by this method requires 15 min for sample preparation and 15 min for the HPLC run. As the system needs no equilibration time (isocratic elution), it is immediately and reproducibility.     

Direct estimation of dolichyl phosphate in rat liver by high pressure liquid chromatography

A method involving reverse-phase high pressure liquid chromatography has been developed for determining the concentration of dolichyl phosphate (Dol-P) in tissues. Individual Dol-P homologs are resolved and amounts as small as 50 ng can be detected. Rat liver was found to contain 2.4 μg Dol-P/g wet weight, or ca. 4% of total liver dolichol. In contrast, rat liver microsomes contained 64 ng Dol-P/mg protein, which is about 40% of total microsomal dolichol. This enrichment in Dol-P is consistent with the role of microsomes as the major site of Dol-P-mediated, glycoprotein biosynthesis in liver     

Quantitative determination of polyethylene glycols in nonionic surfactants by high pressure liquid chromatography

A method employing high pressure liquid chromatography has been developed for the quantitative determination of polyethylene glycols in ethoxylated fatty alcohols and alkylphenols. This technique overcomes many of the limitations encountered in previously-reported methods. The polyethylene glycols are separated from the ethoxylated product and other sample components using a 65/35 acetonitrile/water mobile phase and a Bondapak C₁₈/Corasil reversephase column system. The response factor of the differential refractometer detector is determined using Carbowax standards of appropriate molecular weights. The molecular weight of the polyethylene glycols in each sample is approximated using thin layer chromatography prior to the high pressure liquid chromatography calibration and analysis. The precision of this method for the determination of polyethylene glycols is ± 4% relative or better, and the recovery of added polyethylene glycols is quantitative. Application of this method to a wide variety of commercial ethoxylated fatty alcohols and alkylphenols is presented. Presented at the Meeting of the American Oil Chemists’ Society, April 1976, New Orleans.     

New application of high pressure reversed-phase liquid chromatography in lipids

High pressure reverse-phase liquid chromatography has been used to separate saturated fatty acids, their methyl esters, polyunsaturated fatty acids, and triglycerides. Rapid separation of fatty acids differing in chain length and number of double bonds has been accomplished. Analysis time was less than 10 min in most cases. The high pressure reverse chromatography resulted in better separations of polyenoic acids than can be accomplished by conventional argentation silicic acid column chromatography. The analyses were carried out on a chemically bonded reverse phase packing, VYDAC reverse phase.     

Sorbic acid containing triglycerides in aphids and their fractionation by high pressure liquid chromatography

The sorbic acid containing triglycerides found in various aphid species have been fractionated by high pressure liquid chromatography. Mass spectral analysis afforded identification of three isolates as 2-trans, trans-sorbo-1, 3 dimyristin; 2-trans, trans-sorbo-1,3 myristopalmitin; and 2-trans, trans-sorbo-1,3 dipalmitin. No evidence of asymmetry was found by circular dichroism. The composition and proportions of these triglycerides was found to be species variable.     

Determination of oligosaccharides in soybeans by high pressure liquid chromatography using an internal standard

A method was developed for the quantitative analysis of oligosaccharides in soybeans by high pressure liquid chromatography (HPLC). The sugars were extracted from the soy flour using an ethanol-water solution. Separation of the oligosaccharides was effected by injecting a sample extract onto an HPLC equipped with a μBONDAPAK/carbohydrate® column. Three quantitative techniques were investigated for determining the separate sugars: (a) repetitive injection (i.e., alternately injecting equal volumes of standards and samples); (b) extract analyzed before and after spiking with raffinose (one of the unknowns); (c) the addition of a pure inexpensive internal standard, β-cyclodextrin, which was separated completely from the other oligosaccharides. These methods were successfully applied to the quantitative analyses of two varieties of soybeans and other soybean products such as soy milk and soy protein concentrate.     

Bile acids LVII. Analysis of bile acids by high pressure liquid chromatography and mass spectrometry

Several high pressure liquid chromatographic methods for the separation of conjugated and free bile acids are presented. A mixture of synthetic conjugated bile acids has been separated by reverse-phase systems consisting of either a Waters Associates’ “fatty-acid analysis” or a μBondapak/C₁₈ column eluted with a mixture of 2-propanol/potassium phosphate buffer (pH 2.5 or 7.0). The major conjugated bile acids present in the gallbladder bile of obese subjects have been analyzed each in less than 30 min and quantitated with a U.V. detector set at 193 nm. Some of the 5α- and 5β-isomers of conjugated bile salts could be resolved in straight-phase systems on Corasil II or μPorasil columns. Mass spectra of the conjugated bile acids obtained by electron impact were characteristic of the type of amino acid attached to the side chain, and the number of hydroxyl substituents on the nucleus. Most of the isomers could readily be differentiated by the relative intensities of the fragment ions.     

吡氟草胺的高效液相色谱分析

确立了吡氟草胺原药的高效液相定量分析方法。采用(C18)250×4.6mm(5μm)柱,流动相为甲醇/水(H3PO4pH=3)85∶15(V/V),波长为280nm,线性相关系数为0.9998,回收率为99.47%~100.8%。该方法准确、简便、快速。     

高效液相色谱法测定卷柏中的穗花杉双黄酮

用反相高效液相色谱法测定卷柏提取物中的穗花杉双黄酮。结果表明：穗花杉双黄酮在质量浓度为41.2mg／L～206mg／L时，峰面积Y与其质量浓度X的线性关系良好，回归方程为Y=547．028X 15．4895(r=0.9999)，最低检测限为2．0μg/L；穗花杉双黄酮的平均回收率为99．42％(n=3)，相对标准偏差RSD为0．79％；连续进样、日内进样和日间进样所得检测结果的RSD分别为0．12％、0．11％和0．11％。     

高效液相色谱分析乙酰甲胺磷原药

采用反相高效液相色谱法测定乙酰甲胺磷原药中的有效成分,以甲醇∶水=15∶85(体积比)作为流动相,在波长为215 nm条件下检测乙酰甲胺磷原药有效成分含量,本方法的线性相关系数为0.9999,标准偏差为0.21,变异系数为0.22%,平均回收率为99.75%。