OV-17 Column Research Articles

Gas chromatographic and mass spectrometric analysis of permethylated estrogen glucuronides

Five different estrogen monoglucuronides have been separated at least partially by gas chromatography of the permethyl derivatives on OV-17 columns either isothermally or with temperature programming. The permethyl derivatives are formed quantitatively with a greater than tenfold excess of the methylsulfinylmethide carbanion and methyl iodide. On the other hand, quantitative derivatization (>98%) of the aglycones, estradiol and estriol, is effected only with a thirtyfold or greater excess of the carbanion. Mono-, di-, and trimethyl derivatives are found and all have characteristic mass spectra. The mass spectra of the permethylated glucuronides are also clearly different. All spectra contain molecular ions and fragment ions due to the permethylated glucuronic acid moiety, the aglycones, and M-CH 3OH. This data is being applied to the analysis of intact estrogen glucuronides in body fluids.

Stress metabolite production in potato tubers infected by Phytophthora infestans, Fusarium avenaceum and Phoma exigua

The stress metabolites rishitin, phytuberin, desacetylphytuberin and solavetivone were found in eight different cultivars of potato tuber inoculated with Phytophthora infestans, Fusarium avenaceum and Phoma exigua var. foveata. Concentrations of up to 83 μg rishitin, 409 μg phytuberin, 545 μg desacetylphytuberin and 333 μg solavetivone/g dry weight of infected tissue were found, although not all compounds were detectable in each interaction. Extracts from infected tissue were treated with diazomethane prior to mini-column chromatography which removed interfering apolar compounds including fatty acid methyl esters. Eluates were subjected to analytical gas chromatography on a 10% OV210 column which enabled simultaneous measurement of all four compounds due to a greatly improved resolution compared to the published gas chromatographic procedure for potato stress metabolites. Anhydro-β-rotunol and lubimin, if present in the extracts, could also be quantitatively measured.

Separation of permethylated isomeric glucuronides by gas chromatography and analysis of the mass spectra

Glucuronic acid conjugates of several foreign compounds (1- and 2-naphthols, 2-, 3-, and 4-hydroxybiphenyls, m- and p-hydroxyphenylphenylhydantoins) were produced in the isolated perfused rat liver and identified in the bile as the permethyl derivatives. Permethylated glucuronide isomers were easily separated by gas chromatography on SE-30 and OV-17 columns. The mass spectra of permethylated glucuronide isomers were very similar. Gas chromatography proved to be most useful for the separation and identification of isomeric glucuronides.

An improved technique for the gas-liquid chromatographic separation of the N-trifluoroacetyl n-butyl derivatives of amino acids

A complete separation of the twenty protein amino acids and two internal standards in 35 min has been made possible by analyzing their N-trifluoroacetyl n-butyl (TAB) derivatives simultaneously on an ethylene glycol adipate (EGA) column and on an OV-17 column using the same temperature programme. The detector signal from the EGA column is recorded up to the point just after the elution of TAB-aspartic acid; thereafter, the signal from the effluent of the OV-17 column is recorded. The TAB derivative of norleucine is poorly resolved from TAB-leucine and TAB-proline. Therefore, α-aminocaprylic acid has been used as the internal standard instead of norleucine. TAB-α-aminocaprylic acid appears as a separate peak between TAB-serine and TAB-cysteine.

Gas chromatographic-mass spectral characteristics of aporphine and tetrahydroprotoberberine alkaloids

The gas chromatographic (GC) and mass spectrometric (MS) properties of the silyl derivatives of aporphine and tetrahydroprotoberberine alkaloids are described. Selected representatives of these chemical classes of pharmacologically active bases were chromatographed on polar (OV-17) and nonpolar (OV-1) columns as their trimethylsilyl derivatives. The aporphines were eluted before the tetrahydroprotoberberines on both the polar and nonpolar columns. Simultaneous resolution of mixtures of aporphines and tetrahydroprotoberberines was readily achieved on the OV-1 column. An SE-30 column, used for combined GC-MS analysis, gave a similar resolution of these alkaloids. The mass spectra observed for the silylated 1,2,9,10-substituted aporphines were similar to those of underivatized aporphines, while the mass spectra of the silylated 1,2,10,11-substituted aporphines differed markedly from the spectra of the underivatized alkaloids. Although the mass spectra of the silylated derivatives of the 2,3,9,10- and 2,3,10,11-substituted tetrahydroprotoberberines were identical, these isomeric derivatives were separated by gas chromatography.

High-Performance and Gas-Liquid Chromatography of Methyl Parathion Formulations

Abstract Methyl parathion formulations (a synthetic sample, a technical material, and 6 emulsifiable concentrates) were analyzed by high-performance liquid chromatography (HPLC), gas-liquid chromatography (GLC), and infrared (IR) spectroscopy. The HPLC method used in ultraviolet detector and a Permaphase ODS column with a methanol-water mobile phase. The GLC method used an SE-30/OV-210 column and flame ionization detection. The IR spectrum was recorded at 8.16 μm. A synthetic sample formulated to contain 45.5% methyl parathion (analytical grade) was analyzed 8 times by each method. HPLC yielded an average value of 45.4%, GLC 45.9%, and IR 45.7%. Analyses of variance of this repeatability study showed that the differences between the GLC mean and both the theoretical value and the HPLC mean were small, but significant. Technical methyl parathion and 6 emulsifiable concentrates were analyzed in duplicate by each method. Variance calculations for each set of duplicates by each method indicate a high probability of difference in the methods. High results from the IR analysis are probably due to impurities in the technical material because analysis of the synthetic sample was satisfactory. The HPLC and GLC methods appear to be precise and will be studied collaboratively.

Rapid screening and confirmation of amphetamine, methamphetamine, methadone, and methadone metabolite in urine by gas/thin layer chromatography.

A method suitable for large scale screening and confirmation of urine speciments for amphetamine, methamphetamine, methadone, and its primary metabolite (2-ethylidene-1,5-dimethyl-3,3-diphenlypyrrolidine) is described. The drugs are extracted from alkaline urine into an organic solvent. The amphetamine drugs are then back-extracted into a small volume of acid and identified by gas chromatography both as free bases on a 10% Apiezon L-10% KOH column and as their trifluoracetamide derivatives on a 3% OV-17 column. The organic layer, which still contains methadone and its primary metabolite, is analyzed by split-sample thin-layer chromatography using two solvent systems: ethyl acetate: methylene cloride: concentrated ammonium hydroxide (90:10:0.7) and methanol: chloroform: concentrated ammonium hydroxide (74:25:0.8). These solvent systems separate methadone from its primary metabolite without interference from other drugs or urinary substances.

Gas-Liquid Chromatographic Analysis and Chemical Confirmation of Azodrin (Monocrotophos) Residues in Strawberries

A gas-liquid chromatographic (GLC) method is described for the analysis and confirmation of azodrin (monocrotophos, 3-(dimethoxyphosphinyl)-N-methyl-cis-crotonamide) residues in strawberrires. The strawberries are extracted with acetone, and the filtrate is partioned with a mixture of methylene chloride and petroleum ether followed by further extraction with methylene chloride. The organic phases are combined, dried with anhydrous sodium sulfate, and concentrated to a small volume for GLC analysis on a 3% OV-210 column with flame photometric detection. Identity of the compound is confirmed by chromatography on the same column after trifluoroacetylation of an aliquot of the strawberry extract. The detection limit is about 2 ppb. The types of strawberry samples analyzed were fresh, frozen, pureed, and jam.

Chemical Composition of Technical Chlordane

Abstract Technical chlordane, a multicomponent organochlorine insecticide, was separated into 26 peaks by temperature-programmed gas chromatography, using a 3% OV-17 column. Peaks were identified by using combined gas chromatography-mass spectrometry (GLC-MS) and, where individual standards were available, by comparing retention times on various columns. Technical chlordane constituents were also investigated by GLC-MS, using a Dexsil 300 column; 19–20 peaks were observed. Quantitation studies indicated differences in the per cent contributions of the constituents, particularly for heptachlor and trans-chlordane, in 2 different technical chlordane reference standards. For the same reference standard higher results were obtained by using 63Ni electron capture detection than by using flame ionization detection. By using a combination of 4 GLC columns to overcome peak overlap, we determined that the 11 known constitutents of technical chlordane constituted approximately 40%.

Mass screening and confirmation of barbiturates in urine by RIA/gas chromatography.

A rapid, sensitive and specific procedure is described for the mass screening and confirmation of barbiturates in urine specimens. The method is sensitive to 0.5 mug/ml levels of the commonly used barbiturates. The urine samples are screened by radioimmuno-assay. Specimens screened positive are confirmed by gas-liquid chromatography using a flame ionization detector. The barbiturates are analyzed as free acids on a 10% UC W-98 column and as their dimethyl derivatives on a 3% OV-17 column. This dual approach eliminates false positives caused by interfering substances which may be present in the urine, thus resulting in a method specific for the barbiturates.

A simple and sensitive gas chromatographic method for the determination of clonazepam in human plasma

A simple gas chromatographic method for the determination of clonazepam in human plasma has been developed. After solvent extraction, the compound is measured by an electron capture detector on an OV-17 column. The electron-capture response is linear for 5–120 ng/ml of plasma. There is no interference from other commonly used anti-epileptic drugs or endogenous substrates. Preliminary data from routine monitoring of epileptic patients shows a 10-fold variation in their clonazepam plasma levels.

Gas Chromatography of p-Hydroxybenzoate Esters in Soy Sauce

Trifluoroacetyl (TFA) derivatives of ethyl (PHBA-Et), n-propyl (PHBA-Pr), iso-propyl (PHBA-isoPr), n-butyl (PHBA-Bu) and iso-butyl p-hydroxybenzoate (PHBA-isoBu) in soy sauce were determined by gas-liquid chromatography equipped with hydrogen-flame ionization detector on 2% OV-1 column at 135°C.Determination was made successfully using benzophenone as the internal standard.These esters were separated by steam distillation from samples and extracted with ether.The recovery rates of PHBA-Et, PHBA-Pr, PHBA-isoPr, PHBA-Bu and PHBA-isoBu added to soy sauce were 61.3%, 79.0%, 91.2%, 92.3% and 94.9%, respectively.This method was applied to ten kinds of commercially available soy sauce, and PHBA-isoPr, PHBA-isoBu and PHBA-Bu were found in seven samples and only PHBA-Bu in three samples.

Substances Interfering with the Gas-Liquid Chromatographic Determination of T-2 Mycotoxin

Two substances interfering with the gas-liquid chromatographic (GLC) detection of T-2 mycotoxin were identified as 1-glyceryl-monooleate and 1-glycerylmonolinoleate. These monoglycerides are natural products formed by species of Fusarium growing on cereal grains and are also additives contained in liquid vegetable and animal fats added to the feed mixture. The monoglycerides can be removed from the analytical sample by resolution by thin layer chromatography prior to separation by GLC. Trimethylsilyl ether derivatives of the monoglycerides and T-2 toxin have almost identical retention times on 3% OV-1 columns, whereas the trifluoroacetyl and pentafluoropropionyl derivatives give baseline separation on the same column. The monoglycerides can be misidentified as the T-2 toxin in analyses involbing GLC.

GLC Determination of Hexadiphane in Pharmaceutical Preparations

AbstractA specific, rapid, and sensitive GLC method for purity control of hexadiphane and its determination in pharmaceutical preparations is described. The method utilizes an extraction of the free base, followed by GLC on a 0.5% OV-17 column at isothermal temperature for 6 min and then the temperature was programmed. Results from this method and from a titrimetric method were compared, and no significant differences were found.

Phosphatidylethanolamine molecular species of fatty acid auxotroph of Escherichia coli grown with elaidate

Monoacetyldiglycerides derived from the phosphatidylethanolamine molecular species of the fatty acid auxotroph of Escherichia coli grown with elaidate at 37 °C were fractionated on thin-layer plates of silica impregnated with silver nitrate and were identified by gas chromatography-mass spectrometry with an OV-17 column and gas chromatography with a Silar-10C column. Phosphatidylethanolamine was made up of the following molecular species: 1–16 : 0-2-16 : 0 (1.2%), 1–14 : 0-2-trans-16 : 1 (1%), 1–16 : 0-2-trans-16 : 1 (3.5%), 1–16 : 0-2-trans-18 : 1 (26.4%), 1–16 : 0-2-cis-16 : 1 (3.8%), 1-trans-18 : 1-2-trans-16 : 1 (13.2%), 1-trans-18 : 1-2-trans-18 : 1 (44.9%), 1-trans-18 : 1-2-cis-16 : 1 (4.5%) and trans-18 : 1-cis-18 : 1 (1.5%).

Quantitative gas chromatographic determination of nitrilotriacetic acid in the presence of other carboxylic acids

Nitrilotriacetic acid was separated (as its tri- n-butyl ester) from twenty-four other fatty, phenolic and polycarboxylic acids, using prepacked commercial OV-210 columns. Quantitative analysis down to 0.010 mg nitrilotriacetic acid per liter was demonstrated. The molar responses and retention times of the acids, relative to phthalic acid, were determined.

Quantitative determination of cocaine and its metabolites benzoylecgonine and ecgonine by gas—liquid chromatography

A sensitive and reliable method was developed to determine quantitatively cocaine and its metabolites benzoylecgonine and ecgonine. The method involved the formation of fluoro derivatives which were separated on 3% and 5% OV-1 columns and detected in picomole qunatities using an electron capture detector. Ecgonine and benzoylecgonine were derivatized with a mixture of hexafluoroisopropanol- heptafluorobutyric anhydride (1:2). Cocaine was first reduced by LiAlH 4 and them acylated by pentafluoropropionic anhydride. Benzoylecgonine, but not ecgonine, could also be determined by reduction and subsequent acylation. This provided the basis for the determination of cocaine, benzoylecgonine and ecgonine from the same sample. Cocaine could be determined in urine and plasma by this method.

Determination of Hexachlorobenzene and Mirex in Fatty Products

A procedure is described for the isolation and cleanup of hexachlorobenzene (HCB) and mirex in fats and oils for gas-liquid chromatographic (GLC) analysis. The fat or oil is distributed on unactivated Florisil, and the HCB and mirex are eluted with acetonitrile. The pesticides are then partitioned into petroleum ether. Elution through activated Florisil with methylene chloride-hexane (20+80) is used for the final cleanup. HCB and mirex are then measured by GLC, using the appropriate electron capture conditions with a 15% OV-210 column for HCB and a 3% OV-101 column for mirex. The method demonstrates recoveries greater than 90% for HCB and mirex and allows screening at or below the 0.1 ppm level in fats with a 3 mg fat injection.

9] Gas-liquid chromatography of antibiotics

This chapter discusses the gas-liquid chromatography (GLC) methods for chromatography of intact antibiotic molecules—mainly by derivatization. The chapter discusses some of the difficulties associated with quantitative derivatization and chromatography and describes precautionary measures for the successful GLC determination of antibiotics. Spectinomycin is chromatographed intact as the tetrakistrimethylsilyl derivative using an SE-52 column. Kanamyein is chromatographed intact as the silyl ether-silyl amine derivative using an OV-1 column. Neomycin is ehromatographed intact as the silyl ether-silyl amine derivative using an 0V-1 column. The procedure for the GLC analysis of paromomycin is analogous to that of neomycin powder. It follows the procedure as neomycin powder, using paromomycin in place of neomycin. Griseofulvin is chromatographed intact without derivatization using an OV-1 column. Cycloheximide is derivatized as the monotrimethylsilyl ether by treatment with isopropanol after silylation.

Rapid mass screening and confirmation of urinary amphetamine and methamphetamine by gas chromatography.

A rapid and simple procedure is described for the mass screening and confirmation of amphetamine and methamphetamine in urine using gas chromatography with flame ionization detector. The amphetamine drugs are screened as free drugs on a 10% Apiezon L-10% KOH column and confirmed as their trifluoroacetamide derivatives on a 3% OV-17 column. This dual approach eliminates false positives and interfering substances that may be present in the urine and is, therefore, specific for amphetamine and methamphetamine.