Combined Capillary Gas Chromatography Research Articles

Chemical Composition of the Leaf Oil ofAlpinia chinensisRosc, from Vietnam

ABSTRACT The essential oil of the leaves of Alpinia chinensis Rose. of Vietnamese origin has been analyzed by a combination of capillary gas chromatography and GC/MS. More than 40 components have been identified, of which β-bisabolene (47.9%) was found to be the major one.

The Essential Oil Composition of VietnameseAlpinia breviligulataGagnep. Flowers

ABSTRACT Alpinia breviligulata Gagnep. is a wild plant blooming in August, whose flowers have a characteristic odor. The chemical composition of the flower oil of this plant has been analyzed by a combination of capillary gas chromatography and GC/MS. More than 35 components have been identified, of which α-pinene (12.7%), β-pinene (20.2%) and β-caryophyllene (14.0%) were found to be the main compounds. The components which provide the characteristic aroma are verbenone, bornyl acetate, hedycarvol, (E)-nerolidol, guaiol and β-eudesmol.

The Constituents of the Rhizome Oil ofZingiber zerumbet(L.) Sm. from Vietnam

ABSTRACT The essential oil of Zingiber zerumbet (L.) Sm. from Vietnam, obtained by steam distillation of the rhizomes, has been analyzed by a combination of capillary gas chromatography and GC/MS. More than 30 components have been identified, of which zerumbone is the major constituent (72.3%).

Quantitative analysis of crude plasma extracts by ion trap tandem mass spectrometry

The ion trap mass spectrometer is a tandem-in-time instrument that has promise as an extremely sensitive device for practical tandem mass spectrometry assays. An approach for the quantitative analysis of unknown drug levels in crude extracts, using combined capillary gas chromatography and the ion trap mass spectrometer in the tandem mode, is described. One-gram plasma samples were spiked with an anti-inflammatory drug at levels of 1–100 ng, and with 50 ng of a chemical analog internal standard. Crude extracts of the plasma samples are analyzed by using scan functions that utilize combined radiofrequency (rf) and dc voltages. The need for combined rf- and dc-voltage sequences for analysis of such extracts is demonstrated by comparison to attempted analyses using only rf voltages. Limitations of the method are: (1) the need for accurate calibration of ionization times to obtain linear calibration lines, and (2) the lack of automatic gain control for scans using combined rf and dc voltages to control and optimize parent ion populations and to allow a simpler analysis of “unknowns.”

Highly sensitive method for the determination of 1-methyl-1,2,3,4-tetrahydro-β-carboline using combined capillary gas chromatography and negative-ion chemical ionization mass spectrometry

A sensitive method was developed for the determination of deuterated and non-deuterated 1-methyl-1,2,3,4-tetrahydro-β-carboline by combined capillary gas cheomatography and negative-ion chemical ionization mass spectrometry. 1-Methyl-1,2,3,4-tetrahydro-β-carboline was converted into a trifluoroacetyl derivative after pretreatment with fluorescamine and extraction with ethyl acetate. The derivative was separated by capillary gas chromatography and determined by selected-ion monitoring. In the determination, [3,3,4,4- 2H 4]-1-methyl-1,2,3,4-tetrahydro-β-carboline was used as an internal standard. The method developed in this work was used for the determination of deuterated and non-deuterated 1-methyl-1,2,3,4-tetrahydro-β-carboline in human urine samples collected before and after administration of [3,3- 2H 2]- l-tryptophan.

Pharmacokinetics of Lidocaine and Bupivacaine Following Subarachnoid Administration in Surgical Patients

The pharmacokinetics of lidocaine and bupivacaine following subarachnoid administration were studied in 12 surgical patients using a stable isotope method. After subarachnoid administration of the agent to be evaluated, a deuterium-labelled analogue was administered intravenously. Blood samples were collected for 24 h. Plasma concentrations of the unlabelled and the deuterium-labelled local anesthetics were determined using a combination of capillary gas chromatography and mass fragmentography. Bi-exponential functions were fitted to the plasma concentration-time data of the deuterium-labelled local anesthetics. The progression of the absorption was evaluated using deconvolution. Mono- and bi-exponential functions were then fitted to the fraction absorbed versus time data. The distribution and elimination half-lives of the deuterium-labelled analogues were 25 +/- 13 min (mean +/- SD) and 121 +/- 31 min for lidocaine and 19 +/- 10 min and 131 +/- 33 min for bupivacaine. The volumes of the central compartment and steady-state volumes of distribution were: lidocaine 57 +/- 10 l and 105 +/- 25 l, bupivacaine 25 +/- 6 l and 63 +/- 22 l. Total plasma clearance values averaged 0.97 +/- 0.21 l/min for lidocaine and 0.56 +/- 0.14 l/min for bupivacaine. The absorption of lidocaine could be described by a single first order absorption process, characterized by a half-life of 71 +/- 17 min in five out of six patients. The absorption of bupivacaine could be described adequately assuming two parallel first order absorption processes in all six patients. The half-lives, characterizing the fast and slow absorption processes of bupivacaine, were 50 +/- 27 min and 408 +/- 275 min, respectively. The fractions of the dose, absorbed in the fast and slow processes, were 0.35 +/- 0.17 and 0.61 +/- 0.16, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of the total amount sulfur in petroleum fractions by capillary gas chromatography in combination with cold trapping and a total sulfur analyzer

The distribution of sulfur compounds among fractions of a petroleum liquid has been quantitatively determined by capillary gas chromatographic techniques, including on-column injection, cold-trapping of effluent, and measurement of effective recovery. In this study the amount of sulfur was determined in the gasoline (0–450°F), light cycle oil (450–650°F), and heavy cycle oil (650–11OO°F) fractions of a refinery stream liquid. Knowledge of the amount of sulfur in the various fractions of this material can be valuable in determining how to process this material in the refinery. The petroleum liquid was separated by an on-column injection into a fused-silica capillary column, and the sulfur in each of the three cold-trapped fractions was measured by a hydrogen sulfide total sulfur analyzer. A detection limit of 50 ppm was achieved with quantitative recoveries of almost 100%. The sulfur distributions determined for a series of these petroleum liquids were 0.01–0.02 wt.-% in the 0–450°F fraction, 0.13–0.23 wt.-% in the 450–650°F fraction, and 0.50–1.20 wt.-% in the 650–1100°F fraction. The reproducibility for duplicate samples was 3%, and the reproducibility for the same sample with multiple cold-trap separations was also within 3%. This method obviates the complicated calibration step, which is necessary when sulfur-specific detectors, such as the flame-photometric detector and the Hall electrolytic conductivity detector are used.

Identification of oestrogen metabolites in human urine by capillary gas chromatography and mass spectrometry.

Oestrogen metabolites from the urine of males and pregnant and non-pregnant females were enriched by a procedure involving column chromatography on adsorber resins, gels and ion exchangers, enzymatic solvolysis and extraction, thereby separating the oestrogens from most of the interfering material. After derivatization of the oestrogens as their trimethylsilyl ethers profiles were measured with a fused silica column and a flame ionization detector by gas chromatography. Using a combination of capillary gas chromatography and mass spectrometry approximately 50 oestrogen metabolites were detected in the human urine of males and females, of which 19 were unknown urine compounds. Not all could be identified definitely owing to the lack of reference material. Mass spectra of trimethylsilylated oestrogens with functional groups at position 11 (11-dehydroestradiol, 11-dehydroestrone and 11 beta-hydroxyestrone) were discussed in their common and discernible fragmentations.

Analysis of seed oils containing cyclopentenyl fatty acids by combined chromatographic procedures

The fatty acids of seed oils of the Flacourtiaceae, Hydnocarpus anthelmintica, Caloncoba echinata and Taraktogenus kurzii, have been examined by a combination of capillary gas chromatography, silver ion high performance liquid chromatography and gas chromatography-mass spectrometry. In addition to the common range of cyclopentenyl fatty acids found in such oils, 13-cyclopent-2-enyltridec-4-enoic acid was a major component of H. anthelmintica and was identified by mass spectrometry as its picolinyl ester and dimethyldisulphide adduct. It has not previously been found in nature. In the other seed oils, the isolated double bond in the corresponding fatty acid was in position 6, as expected. Similarly, cis-4-hexadecenoic acid and C16 and C18 cyclopentyl fatty acids were identified for the first time in H. anthelmintica. Iso- and anteiso-methylbranched fatty acids were present in trace amounts.

Identification of methoxylated phenols as candidate tracers for atmospheric wood smoke pollution

More than 70 organic compounds have been identified in unfractionated methylene chloride extracts of soot from residential wood stoves by a combination of capillary gas chromatography coupled with low-resolution mass spectrometry (GC/MS), GC coupled with high-resolution mass spectrometry, and chemical ionization mass spectrometry with deuteriated methanol as the reagent gas. Thirty of the species are derivatives of guaiacol (2-methoxyphenol) and syringol (2,6-dimethoxyphenol), which result from the pyrolysis of wood lignin. Soots from hardwood and pine show similar proportions of the syingol derivatives, but pine soot has much higher proportions of the guaiacol derivatives. Samples collected onto filters backed up by polyurethane foam (PUF) plus in the cooled smoke plume showed that some of the methoxylated phenols were primarily in the vapor phase, while the majority were associated with the particulates. These species are expected to be unique to wood smoke in urban atmospheres and are therefore suggested as tracers for atmospheric wood smoke pollution.

Pharmacokinetics of lidocaine and bupivacaine following subarachnoid administration in surgical patients: simultaneous investigation of absorption and disposition kinetics using stable isotopes.

The pharmacokinetics of lidocaine and bupivacaine following subarachnoid administration were studied in 12 surgical patients using a stable isotope method. After subarachnoid administration of the agent to be evaluated, a deuterium-labelled analogue was administered intravenously. Blood samples were collected for 24 h. Plasma concentrations of the unlabelled and the deuterium-labelled local anesthetics were determined using a combination of capillary gas chromatography and mass fragmentography. Bi-exponential functions were fitted to the plasma concentration-time data of the deuterium-labelled local anesthetics. The progression of the absorption was evaluated using deconvolution. Mono- and bi-exponential functions were then fitted to the fraction absorbed versus time data. The distribution and elimination half-lives of the deuterium-labelled analogues were 25 +/- 13 min (mean +/- SD) and 121 +/- 31 min for lidocaine and 19 +/- 10 min and 131 +/- 33 min for bupivacaine. The volumes of the central compartment and steady-state volumes of distribution were: lidocaine 57 +/- 10 l and 105 +/- 25 l, bupivacaine 25 +/- 6 l and 63 +/- 22 l. Total plasma clearance values averaged 0.97 +/- 0.21 l/min for lidocaine and 0.56 +/- 0.14 l/min for bupivacaine. The absorption of lidocaine could be described by a single first order absorption process, characterized by a half-life of 71 +/- 17 min in five out of six patients. The absorption of bupivacaine could be described adequately assuming two parallel first order absorption processes in all six patients. The half-lives, characterizing the fast and slow absorption processes of bupivacaine, were 50 +/- 27 min and 408 +/- 275 min, respectively. The fractions of the dose, absorbed in the fast and slow processes, were 0.35 +/- 0.17 and 0.61 +/- 0.16, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

On the composition of Achillea abrotanoides (Vis.) Vis. essential oil

AbstractThe essential oil obtained by steam distillation from the dried leaves of Achillea abrotanoides (Vis.) Vis. was analysed by a combination of capillary gas chromatography (CGC), capillary gas chromatography ‐ mass spectrometry (CGC‐MS) and capillary gas chromatography ‐ Fourier transform/infrared spectroscopy (CGC‐FT/ IR). 1,8‐Cineole and camphor accounted for about 32.7% of the oil which contained about fifty compounds most of them present only in traces; 24 components (92.3% of the oil) were characterized.

Electron capture negative ion chemical ionization analysis of arachidonic acid

A highly sensitive (subpicomole level) and structural specific method for the analysis of arachidonic acid esterified to complex glycerophospholipids has been developed using combined capillary gas chromatography and mass spectrometry. The methodology is based upon the formation of the pentafluorobenzyl ester of arachidonic acid, which is efficiently ionized using electron capture negative ion chemical ionization conditions to yield an abundant carboxylate anion at m/z 301. Quantification is carried out following hydrolysis of the complex glycerophospholipid in the presence of a known amount of (2H8) arachidonic acid. The use of this method is illustrated by the quantification of arachidonic acid within the glycerophospholipid classes isolated from resident peritoneal macrophage cells isolated from HS mice.

Sensitive determination of deuterated and non-deuterated indole-3-acetic acid and 5-hydroxyindole-3-acetic acid by combined capillary gas chromatography—negative-ion chemical ionization mass spectrometry

Sensitive methods for the determination of deuterated and non-deuterated indole-3-acetic acid and 5-hydroxyindole-3-acetic acid by combined capillary gas chromatography—negative-ion chemical ionization mass spectrometry were developed. Indole-3-acetic and 5-hydroxyindole-3-acetic acids were converted into pentafluorobenzyl and trifluoroacetylmethyl derivatives, respectively, after prepurification by high-performance liquid chromatography. These derivatives were separated by gas chromatography and determined by selected ion monitoring. In the determinations, indole-3-acetic-2,2,2′,4′,5′,6′,7′-d 7 acid and 5-hydroxyindole-3-acetic-3,3-d 2 acid were used as internal standards. The methods developed in this work were used for the determination of deuterated and non-deuterated indole-3-acetic acid and 5-hydroxyindole-3-acetic acid in human urine samples collected before and after administration of l-tryptophan-3,3-d 2.

Induction of SOS functions in Escherichia coli and biosynthesis of nitrosamine in rabbits by nitrogen dioxide.

Nitrogen dioxide induced SOS functions in Salmonella typhimurium and Escherichia coli K-12 and was mutagenic in Escherichia coli WP2. When a rabbit was administered aminopyrine intravenously and administered nitrogen dioxide by inhalation, N-nitrosodimethylamine was detected in its blood. Analysis was conducted with 15N-nitrosodimethylamine as an internal standard by a combination of capillary gas chromatography and mass spectrometry. Accompanying administration of cystamine increased the blood concentration of N-nitrosodimethylamine in the rabbit, suggesting inhibition of its metabolism. Concurrent sulfur trioxide inhalation increased N-nitrosodimethylamine formation in the rabbit.

Determination of geometric configuration in minute amounts of highly unsaturated termite trail pheromone by capillary gas chromatography in combination with mass spectrometry and fourier-transform infrared spectroscopy

A new method for determination of the stereochemistry of each double bond in minute amounts of highly unsaturated termite trail pheromone is discussed. Micro-chemical reactions, acetylation and partial hydrogenation of the isolated termite trail pheromone, followed by capillary gas chromatography—mass spectrometry (GC—MS) and gas chromatography—fourier-transform infrared spectroscopy analyses of the products are the main procedures employed. The number of double bonds in each partially hydrogenated peak is determined by GC—MS, and the presence or absence of a trans double bond in the corresponding total absorbance monitoring peak is determined from the infrared absorption around 970 cm−1 The structure of the termite (Reticulitermes speratus, Isoptera) trail pheromone was determined as cis-3, cis-6, trans-8-dodecatrien-1-ol.

Determination of geometric configuration in minute amounts of highly unsaturated termite trail pheromone by capillary gas chromatography in combination with mass spectrometry and fourier-transform infrared spectroscopy

A new method for determination of the stereochemistry of each double bond in minute amounts of highly unsaturated termite trail pheromone is discussed. Micro-chemical reactions, acetylation and partial hydrogenation of the isolated termite trail pheromone, followed by capillary gas chromatography—mass spectrometry (GC—MS) and gas chromatography—fourier-transform infrared spectroscopy analyses of the products are the main procedures employed. The number of double bonds in each partially hydrogenated peak is determined by GC—MS, and the presence or absence of a trans double bond in the corresponding total absorbance monitoring peak is determined from the infrared absorption around 970 cm −1 The structure of the termite ( Reticulitermes speratus, Isoptera) trail pheromone was determined as cis-3, cis-6, trans-8-dodecatrien-1-ol.

Sensitive determination of deuterated and non-deuterated tryptophan, tryptamine and serotonin by combined capillary gas chromatography and negative ion chemical ionization mass spectrometry

Sensitive methods for the determination of deuterated and non-deuterated tryptophan, tryptamine and serotonin by combined capillary gas chromatography and negative ion chemical ionization mass spectrometry were developed. [3,3- 2H 2]- l-Tryptophan, which was used as a tracer, was synthesized for studies of their in vivo metabolism. Tryptophan was converted into its trifluoroacetylmethyl derivative after prepurification with an AG 50W-X2 cation-exchange column. Tryptamine and serotonin were extracted with 20% butanol in diethyl ether and derivatized with trifluoroacetic anhydride. These derivatives were separated and determined by selected ion monitoring. In these determinations, [2′,3,3,4′,5′,6′,7′- 2H 7]- d,l-tryptophan, [α,α,β,β- 2H 4]tryptamine and [α,α,β,β- 2H 4]serotonin were used as internal standards.

Sensitive determination of deuterated and non-deuterated phenylalanine and tyrosine in human plasma by combined capillary gas chromatography—negative ion chemical ionization mass spectrometry

A combined capillary gas chromatography—negative ion chemical ionization mass spectrometric method for the determination of deuterated and non-deuterated phenylalanine and tyrosine in plasma was developed. Phenylalanine and tyrosine were converted to pentafluorobenzyl—trifluoroacetyl (PFB—TFA) and PFB—TFA—trimethylsilyl (TMS) derivatives, respectively, after prepurification with a Bio-Rad AG 50W-X2 cation-exchange column. These derivatives showed good gas chromatographic separation properties and provided intense (M  PFB) − ions. These ions were ideal for the specific and sensitive determination of deuterated and non-deuterated phenylalanine and tyrosine by selected ion monitoring assay. [2,2′,3,3,3′,4′,5′,6′- 2H 8] l-Phenylalanine and [2,2′,3,3,3′,5′,6′- 2H 7] l-tyrosine were used as internal standards. This method was used to determine the plasma levels of deuterated and non-deuterated phenylalanine and tyrosine, after oral administration of [2′,3′,4′,5′,6′- 2H 5] l-phenylalanine to a healthy person.

Characterization of Major and Minor Organic Pollutants in Wastewaters from Coal Gasification Processes

Abstract In order to investigate the feasibility of anaerobic biological treatment for wastewaters generated from thermal gasification processes of coal, a characterization program was implemented whose major effort consisted in the elucidation of specific organic constituents contained in the wastewater. Solvent extraction in acid and base conditions followed by glass capillary gas chromatography in combination with several detectors (i.e., FID, NPD, and MS-DS) were employed for the investigation of major and minor “extractable” organic constituents. Direct aqueous injection on a polar glass capillary column (i.e., OV-351) was used for the major “nonsolvent extractable” organic constituents amenable to GC. The identity of 28 organic compounds was confirmed by comparison with pure standards. Phenol, the three cresol isomers, 5,5-dimethyl-hydantoin and 5-methyl,5-ethylhydantoin were identified as major wastewater constituents. Several substituted phenols (e.g., methyl, dimethyl, trimethyl, methylethyl, hyd...