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PubMed1963

CLASSIFICATION OF MICROORGANISMS BY ANALYSIS OF CHEMICAL COMPOSITION. I. FEASIBILITY OF UTILIZING GAS CHROMATOGRAPHY.

Abel, K. (Melpar, Inc., Falls Church, Va.), H. deSchmertzing, and J. I. Peterson. Classification of microorganisms by analysis of chemical composition. I. Feasibility of utilizing gas chromatography. J. Bacteriol. 85:1039-1044. 1963.-The feasibility of utilizing gas chromatography as a sensitive and rapid method for the analysis of lipids as a natural basis for the classification of microorganisms by chemical composition was investigated. The lipids were extracted and transesterified to component carboxylic acid methyl esters in a single step, after which the methyl esters were resolved by gas chromatography to provide distinctive chromatographic elution patterns. Similarities in the lipid carboxylic acid distribution were noted among selected species of the family Enterobacteriaceae, and significant differences were noted among selected families of the class Schizomycetes.

Bacillus anthracis↗
PubMed1981

Purification of tonin by chromatography using soybean trypsin inhibitor coupled CH-sepharose 4B.

Tonin was purified from rat submaxillary gland homogenates by affinity chromatography on soybean trypsin inhibitor coupled CH-Sepharose 4B and two additional steps of conventional chromatography. The use of affinity chromatography by soybean trypsin inhibitor coupled CH-Sepharose 4B permits a new approach in the purification of tonin, since it can completely separate in one step troublesome contamination of the enzymes which showed tosyl-L-arginine methyl ester hydrochloride esterase activity. Tonin is purified 11-fold to a homogeneous state on polyacrylamide gel electrophoresis at a yield of 21%.

Adsorption↗
PubMed2003

Liquid chromatography-tandem mass spectrometry--application in the clinical laboratory.

This review provides a concise survey of liquid chromatography-tandem mass spectrometry (LC-TMS) as an emerging technology in clinical chemistry. The combination of two mass spectrometers with an interposed collision cell characterizes LC-TMS as an analytical technology on its own and not just as a more specific detector for HPLC compared with conventional techniques. In LC-TMS, liquid chromatography is rather used for sample preparation but not for complete resolution of compounds of interest. The instrument technology of LC-TMS is complex and comparatively expensive; however, in routine use, methods are far more rugged compared to conventional chromatographic techniques and enable high-throughput analyses with very limited manual handling steps. Moreover, compared to both gas chromatography-mass spectrometry (GC-MS) and conventional HPLC techniques, LC-TMS is substantially more versatile with respect to the spectrum of analyzable compounds. For these reasons it is likely that LC-TMS will gain far more widespread use in the clinical laboratory than HPLC and GC-MS ever did. In this article, the key features of LC-TMS are described, method development is explained, typical fields of application are discussed, and personal experiences are related.

Chemistry, Clinical↗
PubMed1990

Mass spectroscopy and chromatography of the trichloromethyl radical adduct of phenyl tert-butyl nitrone.

Positive structural identification of the PBN-trichloromethyl spin adduct in vitro was accomplished with the use of high pressure liquid chromatography and/or gas chromatography coupled with mass spectrometry. Both thin layer and liquid chromatography were used to separate a complex mixture of compounds from rat liver extracts treated with CCl4 in vitro and in vivo. Deuterated PBN's (PBN-d9; tert-butyl deuteration, or PBN-d14; both phenyl and tert-butyl deuteration) were also used to aid in the mass spectral analysis of spin adducts from liver extracts of CCl4 exposed rat livers, since the tert-butyl group fragment ion. C4D9+ (m/z = 66) is always present for PBN and PBN spin adducts. In addition, the masses of the ion peaks increase by the amount of deuteration, i.e. an increase of 9 for PBN-d9 or PBN-d14 in comparison to normally synthesized PBN.

Animals↗
PubMed2003

Quantification of aroma compounds in Parmigiano Reggiano cheese by a dynamic headspace gas chromatography-mass spectrometry technique and calculation of odor activity value.

Potentially important aroma compounds in Parmigiano Reggiano cheese were quantified. Free fatty acids were isolated with ion-exchange chromatography and quantified by gas chromatography. Neutral aroma compounds were quantified with a purge-trap/gas chromatography-mass spectrometry with selective mass ion technique. Odor activity values were calculated based on sensory thresholds reported in literature. The calculated odor activity values suggest that 3-methylbutanal, 2-methylpropanal, 2-methylbutanal, dimethyl trisulfide, diacetyl, methional, phenylacetaldehyde, ethyl butanoate, ethyl hexanoate, ethyl octanoate, acetic, butanoic, hexanoic, and octanoic acids are the most important aroma contributors to Parmigiano Reggiano cheese.

Aldehydes↗
PubMed1998

[Advances in chromatography and related techniques in China--status report in 1996-1997].

An overview of the use of chromatography and related techniques in China is given in 1996-1997. This review includes five parts, the statistical results of the scientific papers published in 15 domestic and a few foreign periodicals which are closely related to chromatography and presented on 1997 Beijing Conference and Exhibition on Instrumental Analysis and the 11th National Symposium of Chromatography, about chromatographic theory, GC, LC and CE. One hundred thirty seven references are cited.

Animals↗
PubMed1978

[The use of high-performance liquid chromatography in biochemical and medical analyses (author's transl)].

The HPLC (high-performance liquid chromatography) is applicable for all biochemical analyses, because of the wide variety of separation principles (adsorption-, partition-, ion-exchange- and steric exclusion-chromatography). Of exceptional importance is the reversed phase technique, a special case of partition chromatography. The sensitivity of detectors depends upon the structure of the respective substance, but is ordinarily lower -- apart from fluorescence detection -- than GLC-detectors. The development of new systems is going on. The HPLC is used in the quantitative determination of plasma levels of drugs and their metabolites. This is of special importance during the development of new drugs and for monitoring therapy. The measurement of concentrations of certain biogenic substances helps in diagnosis. An important field of application of HPLC is the use in sample clean-up for other analytical methods. In this application HPLC surpasses all other chromatographic techniques by fastness, reproducibility and suitability for automation.

Adsorption↗
PubMed1984

Multidimensional column liquid chromatography with electrochemical detection for the analysis of terbutaline in human plasma.

Because of low drug concentrations and complex nature of the sample, analytical methods with sensitive and selective detection are necessary for pharmacokinetic studies of terbutaline. Up to now, for non-radiolabelled drugs, usually only methods based on gas chromatography plus mass spectrometry have met these requirements. As an alternative, we have developed an automated method based on liquid chromatography. The necessary sensitivity and selectivity were obtained by using electrochemical detection and a microprocessor-controlled column switching system. The accuracy of the method was compared with a method based on gas chromatography plus mass spectrometry. The overall precision expressed as per cent of the mean was +/- 3.5% and +/- 2.2% at 5 and 50 pmol/mL, respectively. The total absolute recovery for terbutaline and internal standard at these concentration levels were in the range 85-106%.

Autoanalysis↗
PubMed1983

Glycosylated hemoglobin measured by affinity chromatography: micro-sample collection and room-temperature storage.

Under proper conditions, whole blood can be stored at room temperature for as long as 21 days before measurement of glycosylated hemoglobin by affinity chromatography. Whole blood (anticoagulated with EDTA or heparin) was placed in capillary tubes, which were then sealed at both ends and stored at room temperature. Just before assay, whole blood was rinsed from the tubes and diluted 10-fold with water. Samples of each patient's blood were assayed as whole-blood hemolysates by affinity chromatography after zero, seven, 14, and 21 days of storage. Values for glycosylated hemoglobin did not change over 21 days of storage and values for each storage day correlated well (r = 0.97, p less than .0001) with hemoglobin A1C measured in fresh erythrocyte hemolysates by "high-performance" liquid ion-exchange chromatography.

Blood Specimen Collection↗
PubMed1995

Purification of monoclonal antibodies to Le(y) and Le(d) carbohydrate antigens by ion-exchange and thiophilic-adsorption chromatography.

The paper deals with convenient and fast methods for purification of monoclonal antibodies (MAbs) to carbohydrate antigens Le(y) and Le(d) from the cell culture and ascite fluid by ion-exchange chromatography on S-Sepharose and salt-promoted chromatography on a "thiophilic" adsorbent. One-step procedure on S-Sepharose of MAbs to Le(y) (IgG and IgM) provides significant purification (over 90% of contaminants were removed), while a purification factor for IgM to Le(d) is much lower. Highly purified IgM to Le(d) could be obtained by a two-step purification procedure including "thiophilic-adsorption" chromatography and gel-filtration (90-98% of contaminants from the cell culture and ascite fluid were removed). The preparations of IgG and IgM retain their initial antibody activity.

Adsorption↗
PubMed1995

Isolation of ERp72 from guinea pig term placentae using heparin Sepharose affinity chromatography.

The mammalian placenta synthesises many varied antigens, including proteins, such as hormones, enzymes and protease inhibitors. In this report, we isolated and purified the two protein isomerase-related protein precursor ERp72 isoforms from aqueous extracts of guinea pig placenta, by four (4) chromatographic procedures; i) affinity chromatography on immobilised heparin, ii) gel filtration (Ultrogel AcA-54), iii) anion exchange chromatography (Mono-Q), and, iv) negative immunoaffinity chromatography. From 20 term placentae, the final yield of ERp72 isoforms was 2.4mg (Mr 71.5 kDa) and 1.5mg (Mr 75.8 kDa). Identity was confirmed by NH2-terminal amino acid sequencing which demonstrated 85% homology to human ERp72. By indirect immunofluorecence. ER p72 expression was demonstrated in tunicamycin stressed pre-implantation embryos and unfertilised oocytes. These findings demonstrate the potential for immunological monitoring of ERp72 expression, by cultured oocytes and embryos, during manipulation by assisted reproductive technologies.

Amino Acid Sequence↗
PubMed1980

The glucose transport activity of human erythrocyte membranes. Reconstitution in phospholipid liposomes and fractionation by molecular sieve and ion exchange chromatography.

Human erythrocyte membranes, at a protein concentration of 1-2 g/l, were solubilized with 0.12 M cholate in the presence of 0.06 M phospholipid (egg yolk phospholipids or phosphatidylcholine). More than 40% of the protein was solubilized. Cholate was removed by molecular sieve chromatography, whereby liposomes formed. These liposomes exchanged D-glucose faster than L-glucose. The recovery of glucose transport activity in the reconstituted system was estimated to be higher than 16%. The liposomes were heterogenous in size, as shown by molecular sieve chromatography on Sepharose 4B, and small liposomes predominated. In liposomes formed with phosphatidylcholine, the distribution of glucose transport activity did not parallel the distribution of protein or phospholipid, and the activity was found mainly in the smallest liposomes. The proteins were incorporated mainly in the liposomes that eluted at the lowest ionic strength upon ion exchange chromatography. The glucose transport activity separated into three main peaks upon ion exchange chromatography of egg yolk phospholipid liposomes. The activity eluted at low ionic strength. The liposomes contained proteins mainly from the 3- and 4.5-regions (nomenclature according to Steck, T.L. (1974) J. Cell Biol. 62, 1-19). The activity peaks were highest in the first part of the chromatogram. The protein distribution did not coincide with the variation in activity over each peak. Therefore, it cannot be excluded that a minor component not seen in the electrophoretic analyses might be responsible for the glucose transport activity.

Biological Transport, Active↗
PubMed2001

A four-column parallel chromatography system for isocratic or gradient LC/MS analyses.

A novel approach to parallel liquid chromatography/ tandem mass spectrometry (LC/MS/MS) analyses for pharmacokinetic assays and for similar quantitative applications is presented. Modest modifications render a conventional LC/MS system capable of analyzing samples in parallel. These modifications involve the simple incorporation of three valves and four LC columns into a conventional system composed of one binary LC pumping system, one autosampler, and one mass spectrometer. An increase in sample throughput is achieved by staggering injections onto the four columns, allowing the mass spectrometer to continuously analyze the chromatographic window of interest Using this approach, the optimized run time is slightly greater than the sum of the widths of the desired peaks. This parallel chromatography unit can operate under both gradient and isocratic LC conditions. To demonstrate the utility of the system, atorvastatin, five of its metabolites, and their deuterated internal standards (IS) were analyzed using gradient elution chromatography conditions. The results from a prestudy assay evaluation (PSAE) tray of standards and quality control (QC) samples from extracted spiked human plasma are presented. The relative standard deviation and the accuracy of the QC samples did not exceed 8.1% and 9.6%, respectively, which is well within the acceptance criteria of the pharmaceutical industry. For this particular analysis, the parallel chromatography system decreased the overall run time from 4.5 to 1.65 min and, therefore, increased the overall throughput by a factor of 2.7 in comparison to a conventional LC/MS/MS analytical method.

Journal Article↗
PubMed1968

Gas-liquid chromatography of trimethylsilyl derivatives of abscisic Acid and other plant hormones.

This paper describes a new method for qualitative and quantitative assay of abscisic acid and other acidic plant hormones, such as indoleacetic acid and the gibberellins, by the gas-liquid chromatography of their trimethylsilyl derivatives. Interfering substances in plant extracts were largely removed by preliminary column chromatography with carbon-celite and elution of the abscisic acid with 60% acetone, permitting direct determination of abscisic acid by gas-liquid chromatography using a flame ionization detector. (A level of 0.65 mg/kg fr wt was found.) This method enables measurement of amounts of abscisic acid as low as 0.025 mug. In impure samples collected by gas-liquid chromatography the abscisic acid recovered could be measured quantitatively by use of its ultraviolet absorption maximum at 260 mmu.

Journal Article↗
PubMed1987

Formation of delta-Aminolevulinic Acid from Glutamic Acid in Algal Extracts : Separation into an RNA and Three Required Enzyme Components by Serial Affinity Chromatography.

Extracts from plant chloroplasts and algae catalyze the conversion of glutamate to delta-aminolevulinic acid (ALA) in the first committed step of the tetrapyrrole biosynthetic pathway leading to chlorophylls, hemes, and bilins. The conversion requires ATP, Mg(2+), and NADPH as cofactors. Soluble extracts from Chlorella vulgaris have now been resolved into four macromolecular fractions, all of which are required to reconstitute activity. One fraction contains a low molecular weight RNA which can be separated from the protein components in an active high-speed supernatant by treatment with 1 molar NaCl followed by precipitation of the proteins with (NH(4))(2)SO(4) at 70% saturation. The proteins recovered from the (NH(4))(2)SO(4) precipitate are reactivated by addition of a fraction containing tRNAs isolated from Chlorella by phenol-chloroform extraction and DEAE cellulose chromatography. Three required protein fractions were resolved from the RNA-depleted (NH(4))(2)SO(4) precipitate by serial affinity chromatography on Reactive Blue 2-Sepharose and 2',5'-ADP-agarose. Glycerol was found to stabilize the enzyme activity during the separation process. The majority of the glutamate:tRNA ligase activity was associated with the fraction which was retained by Blue-Sepharose and not retained by ADP-agarose, in agreement with the reported properties of the affinity ligands. The active material in the fraction not retained by Blue-Sepharose eluted as a single component on gel filtration chromatography, with an apparent molecular weight of 67,000. The active component in the RNA fraction also eluted as a single component on gel filtration chromatography.

Journal Article↗
PubMed2006

High-performance liquid chromatography-ultraviolet-visible spectroscopy-electrospray ionization mass spectrometry method for acrylic and polyester forensic fiber dye analysis.

A critical point of comparison between a fiber collected from a crime scene and a fiber from a known source is the color. Fiber dye analysis using thin-layer chromatography or ultraviolet (UV)-visible (Vis) microspectrophotometry provides useful, although limited, data for comparison. High-performance liquid chromatography-electrospray ionization mass spectrometry (LC/MS) overcomes these limitations by integrating chromatography, ultraviolet-visible spectroscopy, and mass spectrometry into a single instrument. In order to evaluate the applicability of the LC/MS to forensic fiber dye analysis, a multi-stage chromatographic method using acidified water and acidified acetonitrile was developed that separated and identified a mixture of 15 basic and 13 disperse dye standards. The LC/MS also detected and analyzed dyes extracted from individual 0.5 cm acrylic and polyester fibers, demonstrating its applicability to this type of analysis. With regard to the analysis of disperse dyes in polyester fibers, the replacement of pyridine with acetonitrile in the extraction system allowed direct injection of the extracts into the LC/MS. The advantage of the LC/MS over other instrumental methods of textile dye analysis is demonstrated by the analysis and differentiation of three black acrylic fibers: two fibers had similar UV-Vis spectra but were differentiated with chromatography and two had similar UV-Vis spectra and chromatograms but were differentiated using the mass spectrometer.

Journal Article↗
PubMed1997

[Columns and separation mechanism of low pressure ion chromatography].

Ion chromatography which appeared in 1975 has been developed rapidly in recent years. But the working pressure increased with years. In this work, the authors put forward the low pressure ion chromatography (LPIC) and successfully designed several kinds of low pressure ion chromatography with inlet pressure of 1.92 x 10(5)-2.94 x 10(5) Pa. Many cations, such as, alkali metals, NH4+, alkaline earth metals, transition metals, inorganic anions and organic acidic ions can be analyzed rapidly by the technique. The detectable limit of numerous ions reaches 10(-6) g/L. Low working pressure, high performance separation and highly sensitive detection can be realized by LPIC. Among these, the columns play an important part. In this paper, the kinds and species of columns and the analytes are presented. The separation mechanism of low pressure ion chromatography is discussed, which indudes ion exchange equilibrium, complexation equilibrium and ion exclusion reaction. Furthermore, the relation between the exchange capacity of ion exchange media and the concentration of eluent are also discussed. In the meanwhile, the choice of LPIC elution systems and separation conditions are described in this paper too.

English Abstract↗
PubMed1999

Enantiomer-specific high-performance liquid chromatography with fluorescence detection of methamphetamines in abusers' hair and urine.

Enantiomer-specific high-performance liquid chromatography with fluorescence detection using 4-(4,5-diphenyl-1H-imidazol-2-yl)-benzoyl chloride as a fluorescence labeling reagent was applied to determine methamphetamine and its metabolites in abusers' hair and urine. Hair samples were segmentally analyzed based on 1 cm long segments. In four hair samples, only the S(+)-enantiomers of methamphetamine and its N-demethylated metabolite, S(+)-amphetamine were detected. Satisfactory correlation (r = 0.901) between the results of high-performance liquid chromatography-fluorescence and those of gas chromatography-nitrogen phosphorous detection was obtained (n = 19). In an abuser's urine sample, the S(+)- and R(-)-enantiomers of methamphetamine, amphetamine and para-hydroxymethamphetamine were detected. The degree of N-demethylation of S(+)-methamphetamine into the corresponding metabolite of amphetamine was significantly higher than that of the R(-)-enantiomer.

Chromatography, Gas↗