Liquid chromatographic determination of the species composition of membrane lipids and their derivatives

This review gives quantitative results of the separation of individual classes of polar glycerolipids of natural and synthetic origin into their individual species. Universal quantitative criteria calculated from the fatty-acid composition of the species obtained or of their mixtures are proposed for determining the degree of reliability of these results. The fractionation of the initial acyl-containing glycerolipids, their N- and O-derivatives with high hydrophobicity, the products of the enzymatic hydrolysis of the native lipids (diacylglycerols, phosphatidic acids) and also the lipophilic O-derivatives of these products is considered. For all these compounds, the results of their separation by the methods of TLC and HPLC both in the form of the adsorption chromatography of the coordination complexes with silver and also in the form of reversed-phase chromatography are discussed. Institute of Plant Physiology of the USSR Academy of Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 453–477, July–August, 1989.     

The chemical composition of the essential oil of the larch

Summary The essential oils of various species of larch have been separated by gas-liquid chromatography under conditions of linear temperature programming.Of the 45 compounds present in each of the essential oils, 32 components have been identified, 16 of which have not previously been found in larch essential oil.The chemical compositions of the oxygen-containing and sesquiterpene hydrocarbons of four species and one variety of larch have been studied. It has been shown that there is no quantitative difference between the compositions of the individual species of larch and only their quantitative compositions differ.Voronezh Institute of Wood Technology. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 456–462, July–August, 1976.     

Identification of natural dyes used in works of art by pyrolysis–gas chromatography/mass spectrometry combined with in situ trimethylsilylation

Samples of four natural dyes from different organic families—natural madder (anthraquinonoid), curcuma (curcuminoid), saffron (carotenoid) and indigo (indigotic)—were analysed using a new procedure based on pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS), which includes the on-line derivatisation of the natural dyes using hexamethyldisilazane (HMDS). In addition, a previous procedure involving the addition of a 10% H₂SO₄ aqueous solution to the dye and further separation with ethyl acetate has been tested. This procedure enhances the sensitivity of the method by extracting the colouring compounds from the rest of the compounds present in the natural dye. Two possible derivatising reagents—HMDS and tetramethylammonium hydroxide (TMAH)—were compared in order to assess their effectiveness in the proposed method. Characteristic peaks from trimethylsilyl derivatives of alizarin, quinizarin, xanthopurpurin and purpurin were obtained for madder; peaks from safranal, isophorone and trimethylsilyl derivative of crocetin for saffron; peaks from 4-(4-hydroxy-3-methoxy)phenyl-3-buten-2-one and 4-(4-hydroxy-3-methoxy)phenyl-2-butanone, which are primary pyrolysis products of curcuma, and peaks from indole, 2-methylindole and 2,3-dihydroindol-2-one, which are primary pyrolysis products of indigo, among others, were obtained. The reported procedure leads to the unambiguous identification of the four studied dyes from solid samples formed by individual dyes.Electronic Supplementary Material Supplementary material is available for this article at     

Gas chromatography with open tubular columns of cyclododecane derivatives

It was demonstrated that gas chromatography with open tubular columns can be used for the separate determination of certain cyclododecane derivatives that are used as the perfume compounds in the perfume industry, their derivatives, and their intermediate products. The retention indices of some cyclododecane derivatives on stationary phases with different polarities were determined. Possibilities of the separation of isomeric products with similar properties were revealed.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 4, 2005, pp. 394–397.Original Russian Text Copyright © 2005 by B. Rudenko, G. Rudenko.     

Elucidation of the Lipid Composition of Hemp (Cannabis sativa L.) Products by Means of Gas Chromatography and Ultra-High Performance Liquid Chromatography Coupled to Mass Spectrometry Detection

The growing demand in natural matrices that represent a source of dietary and nutraceutical molecules has led to an increasing interest in Cannabis sativa, considered to be a multipurpose, sustainable crop. Particularly, the considerable content in essential fatty acids (FAs) makes its derived-products useful food ingredients in the formulation of dietary supplements. In this research, the FA and triacylglycerol (TAG) composition of hempseed oils and flours were investigated using gas chromatography coupled to mass spectrometry and flame ionization detection as well as liquid chromatography coupled to mass spectrometry (LC-MS), respectively. Furthermore, a recently introduced linear retention index (LRI) approach in LC was successfully employed as a useful tool for the reliable identification of TAG species. A total of 30 FAs and 62 glycerolipids were positively identified in the investigated samples. Relative quantitative analyses confirmed linoleic acid as the most abundant component (50–55%). A favorable omega6/omega3 ratio was also measured in hemp-derived products, with the α-linolenic acid around 12–14%. Whereas, γ-linolenic acid was found to be higher than 1.70%. These results confirm the great value of Cannabis sativa as a source of valuable lipids, and the further improvement of the LRI system paves the way for the automatization of the identification process in LC.     

THM PyGC–MS of wood fragment and vegetable fibre forensic samples

Wood fragments and vegetable fibres were investigated using thermally assisted hydrolysis and methylation with pyrolysis gas chromatography–mass spectrometry (THM PyGC–MS). Multiple ion chromatography was used to decrease the interference from cellulosic peaks, and to obtain greater resolution between the lignin peaks. Forty-four wood samples were analysed using THM PyGC–MS. The wood fragments were able to be differentiated into angiosperms (hardwoods) and gymnosperms (softwoods) using principle component analysis (PCA), hierarchical cluster analysis (HCA), and the ratio of syringyl to guaiacyl lignin fragments (S/G ratio). PCA and HCA also differentiated several Monterey pine samples from the rest of the gymnosperms, primarily by the presence of β-pinene, an extractive compound. Other gymnosperm species and the individual angiosperm species were unable to be differentiated. A pilot study investigating the use of THM PyGC–MS for the analysis of vegetable fibres in forensic science found that the fibre types tended to group into two clusters, with one containing cotton, hemp and linen; and the other consisting of hessian, sisal, jute and coir. The seagrass sample was able to be differentiated from both groups. These groups were well separated using PCA, HCA and by the ratio of cinnamyl phenolic derivatives to guaiacyl lignin derivatives (C/G ratio). Some grouping of each fibre type was evident within each cluster, however the separation between the clusters was insufficient to differentiate them using these statistical techniques. THM PyGC–MS of vegetable fibres showed some potential for future use in forensic science.     

Separation of linear gramicidins using carbon dioxide-containing mobile phases

Packed-column supercritical-fluid chromatography (pSFC) is presented as a novel method for separating and analyzing gramicidin samples. By use of methanol-modified carbon dioxide as a mobile phase the pentadecapeptides gramicidin A (gA), gramicidin B (gB), and gramicidin C (gC) are readily separated and eluted from a PRP-1 poly(styrene–divinylbenzene) column. Although optimum separation conditions are typically achieved near a column temperature of 40°C, a column pressure of 11 MPa, and 30% methanol modifier, pressure and modifier gradients around these values are also found to improve the overall separation time. Measurements indicate that the mobile phase solubility of gramicidin under these conditions is 5.0±0.4 g mL^–1. Collection of individual peaks during chromatography achieved analytical-scale isolation of 2 g refined gC from 20 g injected gramicidin D. Further, supercritical-fluid extraction of 200 g gramicidin D from a Chromosorb 102 support packed into the vessel produced 57 g gA in 90% purity. The results establish that carbon dioxide-based mobile phases can be successfully used for the separation of individual gramicidin species.     

Analysis of products from hydrogenation of 2-butyne-1,4-diol

Conclusions A qualitative and quantitative method has been developed for analysis of a mixture of butane-1,4-diol, cis-2-butene-1,4-diol, trans-2-butene-1,4-diol, and 2-butyne-1,4-diol in the form of their diacetates by gas chromatography.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 942–944, April, 1970.     

Determination of tetracyclines in plasma by high-performance liquid chromatography

A new method for the separation and quantitative determination of certain anti-biotics of the tetracycline series in blood plasma by high-performance liquid chromatography on a column filled with Partisil PXP 5 silica gel is described.I. M. Sechenov First Moscow Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 376–379, May–June, 1981.     

Simultaneous determination of C1−C8 n-alkyl acetates and corresponding mono-, di- and trichloroacetates on glass capillary columns with programmed temperature rise

Summary Gas chromatography of mixtures of aliphaticn-alkyl acetates (CH₃–COOR), chloroacetates (CHCl₂–COOR), dichloroacetates (CHCl₂–COOR) and trichloroacetates (CCl₃–COOR), where the alcohol chain length (R) varied between 1 and 8, has been studied on SE-30, Carbowax 20M and OV-351 glass capillary columns with programmed temperatures from 50°C at 2, 4, 6, 8 and 10°C/min. Compounds in the homologous series are eluted in the direct order from methyl ton-octyl acetate. The isomeric chloro esters are eluted on SE-30 according to their boiling points in the order: mono-, di- and trichloro isomer, whereas on polar columns di- and trichloro esters are eluted in the reverse order. The complete separation of all 32 individual components from the mixture could not be reached by any single column, the best separation occurred on SE-30. The mixture can, however, be separated by using columns with polar and non-polar stationary phases. The relative retention times for the compounds are given and the retention order discussed.     

Mannich reaction in a number of six-membered heterocyclic γ,-ketones. X. Stereochemistry of the reduction and phenylation of 2, 2-dimethyl-5-dimethylaminomethyl-4-oxotetrahydropyran

2, 2-Dimethyl-5-dimethylaminomethyl-4-oxotetrahydropyran was subjected to reduction with lithium aluminum hydride, sodium borohydride, aluminum isopropoxide, and lithium in liquid ammonia, to catalytic hydrogenation over Raney nickel, and phenylation with phenyllithium. The quantitative ratios in the resulting mixtures of stereoisomeric 2, 2-dimethyl-5-dimethylaminomethyl-4-hydroxytetrahydropyrans and their dependence on the character of the reducing agents were established by means of gas — liquid chromatography and PMR spectroscopy. The individual geometrical isomers of the amino alcohols were isolated, and their three-dimensional structures were studied by means of their PMR and IR spectra.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 611–616, May, 1976.     

Chemical investigation ofHippopha? rhamnoides. II. Main components of the neutral reaction of the saponification products of an extract of the leaves of the sea buckthorn

The qualitative and quantitative compositions of the neutral fraction of the products of the saponification of a diethyl ether extract of a sea buckthorn leaves have been investigated. Fourteen triterpene compounds and eight aliphatic alcohols have been identified from the results of GLC, CMS, and PMR and also from their melting points.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Institute of Catalysis, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 514–519, July–August, 1985.     

Analysis of Biogenic Amines Using Immunoassays,HPLC, and a Newly Developed IC-MS/MS Technique in Fish Products—A Comparative Study

In this study, comparative analyses were carried out with ion chromatography mass-spectrometry (IC-MS/MS) which has no derivatization step, high-performance liquid chromatography (HPLC) technique, as well as two quantitative and two semi-quantitative immunoassays. The results demonstrated that HPLC and quantitative immunoassay methods were well-correlated with IC-MS/MS in determining histamine in various types of fish products. The best correlation was observed with the HistaSure ELISA Fast Track kit (R² = 0.9903). More than half of the values (68%) obtained by two methods were also statistically similar. The results of semi-quantitative test kits also supported histamine values estimated by quantitative methods, with some exceptions. The best results were found for HistaSure Lateral Flow in supporting the quantitative techniques. Therefore, these methods are found suitable for monitoring histamine in fish products in terms of food safety. Good correlations were also observed HPLC and IC-MS/MS in determining cadaverine, putrescine, and tyramine with the highest value observed for tyramine as R² = 0.9785. However, no correlation was observed for other biogenic amines, and the majority of the results were significantly different from each other for these amines (p < 0.05). The differences may be caused by the drawbacks reported previously for HPLC. However, further studies are required to confirm the possible effects. This study provides a comparative evaluation of several methods in terms of their suitability in determining biogenic amines in fish products for both monitoring and regulatory purposes.     

Lipid profiling of cyanobacteria Synechococcus sp. PCC 7002 using two‐dimensional liquid chromatography with quadrupole time‐of‐flight mass spectrometry

Glycerolipid is a main component of membranes in oxygenic photosynthetic organisms. Up to now, the majority of publication in this area has focused on the physiological functions of glycerolipids and lipoprotein complexes in photosynthesis, but the study on the separation and identification of glycerolipids in thylakoid membrane in cyanobacteria is relatively rare. Here we report a new method to separate and identify five photosynthetic glycerolipid classes, including monoglucosyl diacylglycerol, monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and phosphatidylglycerol, in cyanobacteria Synechococcus sp. PCC 7002 by two‐dimensional (normal‐ and reversed‐phase) liquid chromatography online coupled to quadrupole time‐of‐flight mass spectrometry. Over twice as many lipid species were detected by our method compared to the previously reported methods. Ten new odd‐chain fatty acid glycerolipids were discovered for the first time. Moreover, complete separation of isomers of monogalactosyl diacylglycerol and monoglucosyl diacylglycerol was achieved. According to the tandem mass spectrometry results, we found that the head group of monoglucosyl diacylglycerols was not as stable as that of monogalactosyl diacylglycerols, which might explain why the organism chose monogalactosyl diacylglycerols and digalactosyl diacylglycerols instead of monoglucosyl diacylglycerols as the main content of the photosynthetic membranes in the history of evolution. This work will benefit further research on the physiological function of glycerolipids.     

Effect of temperature on the selectivity of the extraction of lanthanides with dibutylphosphoric acid from thiocyanate solution

Extraction coefficients and separation factors of all lanthanides were determined in the system: dibutylphosphoric acid /HDBP/ - 3M NH₄NCS, in the temperature range of 15–50 °C. The values for the separation factors for such pairs as: Gd–Tb and Er–Tm, are higher than 4, those for the pair of Tb–Dy are higher than 3, and those for the La–Ce, Pm–Sm, Dy–Ho, Ho–Er and Tm–Yb pairs are higher than 2. The influence of temperature on the separation factors of light /La–Gd/ and heavy /Gd–Lu/ lanthanides is discussed and compared with that observed for the extraction from the nitric acid solutions. The results are also discussed in the light of the double-double effect and outer-, vs. inner-sphere complexation in the lanthanide series.     

Mass-spectrometric characteristics of the molecular species of cotton-plant phosphatidylcholine

Summary The quantitative identification of the molecular species of phosphatidylcholine in the form of their monoacetyldiglycerides has been performed by a mass-spectrometric method.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 305–307, May–June, 1978.     

Die quantitative Bestimmung der Sulfons?uren von Phenol, Naphthalin und Anthrachinon durch Chromatographie an S?ulen aus Cellulosepulver

Zusammenfassung Die quantitative Analyse von Sulfonsäuren des Phenols, des Naphthalins und des Anthrachinons durch Säulenchromatographie an Cellulosepulver wird beschrieben. Die einzelnen Säuren werden mit Gemischen aus n-Propanol-Chloroform-Wasser eluiert und alkalimetrisch bestimmt. Von den Phenolsäuren kann man das o- und p-Isomere sowie die Schwefelsäure bestimmen. Von den Naphthalinsulfonsäuren wird der Gehalt an Monound Disulfonsäuren sowie an Schwefelsäure bestimmt. Von den Derivaten des Anthrachinons lassen sich die 1-Sulfon-, sowie 1,5- und 1,8-Disulfonsäuren trennen. Von den nichtkatalytisch sulfonierten Produkten läßt sich der Gehalt an Mono-, an Disulfonsäuren und an Schwefelsäure bestimmen, sowie das Verhältnis zwischen 1- und 2-Anthrachinonsulfonsäuren. Eine Analyse dauert ungefähr 1–3 Std.

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Summary A quantitative analysis of sulphonic acids of phenol, naphthalene and anthraquinone by column chromatography on cellulose powder is described. The separation of the acids is achieved by elution of the sample with a propanol-chloroform-water mixture and the obtained individual acids are estimated by alcalimetric titration. By this method the determination of the para- and ortho-isomers of phenol sulphonic and sulphuric acid is possible. The naphthalenesulphonic acids are also separated and the amounts of sulphuric acid, mono- and disulphonic acids are determined. From the derivates of anthraquinone the separation of 1-sulphonic, 1,5- and 1,8-disulphonic acids is suecesfully performed. In the products obtained by non-catalytical sulphonation the mono-, disulphonic and sulphuric acids may be determined, also the ratio of 1- to 2-anthraquinone sulphonic acids. About 1–3 hours are required for a complete analysis.

     

Separation of species of radionuclides from precipitation and fallout samples

The experience with determination of species of radionuclides using the method based on in-line separation of these species by filtration and retention on columns of cation and anion exchange resins and activated charcoal, respectively, is presented. For the combined precipitation and fallout samples from the point of view of their sampling passive and indicatively active arrangements of the method have been proved. During 1984–1986 some real samples from the locality of the Institute have been analyzed, obtained results are briefly discussed and evaluated.     

Current state of the liquid column chromatography of coumarins

An analysis is given of literature information on the liquid column chromatography of coumarins for 1983–1990. Questions of the classification of the methods used, the choice of the optimum detection regime, and the conditions of chromatographic separation are discussed. The relationship between the structures of coumarins and their chromatographic behavior is considered. Conditions for the separation, isolation, and analysis of coumarins in various materials are given.Kemerov State Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 155–172, March–April, 1992.     

Application of Multivariate Calibration Techniques to HPLC Data for Quantitative Analysis of a Binary Mixture of Hydrochlorathiazide and Losartan in Tablets

New multivariate approaches have been applied to high-performance liquid chromatography (HPLC) with multiwavelength photodiode-array (PDA) detection. Multivariate calibration techniques such as partial least squares (PLS), principal component regression (PCR), classical least squares (CLS), and inverse least squares (ILS) was subjected to HPLC data for simultaneous quantitative analysis of synthetic binary mixtures and a commercial tablet formulation containing hydrochlorothiazide (HCT) and losartan potassium (LST). The combined use of HPLC and multivariate calibrations has been denoted HPLC–CLS, HPLC–ILS, HPLC–PCR, and HPLC–PLS. Successful chromatographic separation of the two active compounds and enalapril maleate, used as internal standard (IS), was accomplished by means of a 4.6 mm i.d. × 250 mm, 5 m particle, Waters Symmetry C₁₈ reversed-phase column and a mobile phase consisting of 60:40 acetate buffer (0.2 M, pH 4.8)–acetonitrile (v/v, 60:40). HPLC data based on the ratio of analyte peak areas to IS peak area were obtained by PDA detection at five-wavelengths (250, 255, 260, 265, and 270 nm). The HPLC–CLS, HPLC–ILS, HPLC–PCR, and HPLC–PLS calibration plots for hydrochlorothiazide and losartan potassium were constructed separately by using the peak-area ratios corresponding to the concentrations of each active compound. The HPLC multivariate calibrations obtained were tested for different synthetic mixtures containing HCT and LST in the presence of the IS. These multivariate chromatographic methods were also applied to a commercial pharmaceutical dosage form containing HCT and LST. The results obtained from the multivariate calibrations were compared with those obtained by use of another, classical HPLC method using single-wavelength detection.Revised: 29 September 2004 and 4 January 2005