Quantitative Organic Analysis Research Articles

Fast and accurate quantitative organic acid analysis with LC-QTOF/MS facilitates screening of patients for inborn errors of metabolism

Since organic acid analysis in urine with gaschromatography-mass spectrometry (GC-MS) is a time-consuming technique, we developed a new liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) method to replace the classical analysis for diagnosis of inborn errors of metabolism (IEM). Sample preparation is simple and experimental time short. Targeted mass extraction and automatic calculation of z-scores generated profiles characteristic for the IEMs in our panel consisting of 71 biomarkers for defects in amino acids, neurotransmitters, fatty acids, purine, and pyrimidine metabolism as well as other disorders. In addition, four medication-related metabolites were included in the panel. The method was validated to meet Dutch NEN-EN-ISO 15189 standards. Cross validation of 24 organic acids from 28 urine samples of the ERNDIM scheme showed superiority of the UPLC-QTOF/MS method over the GC-MS method. We applied our method to 99 patient urine samples with 32 different IEMs, and 88 control samples. All IEMs were unambiguously established/diagnosed using this new QTOF method by evaluation of the panel of 71 biomarkers. In conclusion, we present a LC-QTOF/MS method for fast and accurate quantitative organic acid analysis which facilitates screening of patients for IEMs. Extension of the panel of metabolites is easy which makes this application a promising technique in metabolic diagnostics/laboratories.

Sensory and chemical interactions of food pairings (basmati rice, bacon and extra virgin olive oil) with banana

The aim of this study aimed to investigate food pairings as an important sensory phenomenon in order to determine how different components in the selected food pairings affect and interact with other components. Three novel food pairings (banana and bacon, banana and olive oil, and banana and rice) were selected. A conjoint approach utilising qualitative (organic volatile analysis and descriptive sensory analysis) and quantitative (comparable semi quantitative organic volatile analysis and affective sensory tests) methods of analysis n an attempt to elucidate the success or failure of selected food pairings. Free choice profiling (descriptive sensory analysis) data was analysed using Generalised Procrustes analysis. The correlation between volatile analysis and descriptive sensory analysis results were analysed using ANOVA partial least squared regression. Hedonic results were analysed using a Friedman rank sum test, while preference results were analysed using a Wilcoxon signed rank test. The food pairings of banana and bacon and banana and rice were found to be liked significantly more than banana and olive oil. The results of this study suggest that synergistic and/or antagonistic interactions between the volatile compounds in the foods influenced the hedonic ratings of these food pairings.

Re-Examining the Research School: August Wilhelm Hofmann and the Re-Creation of a Liebigian Research School in London

This paper has a number of inter-related goals concerning research school methodology, nineteenth-century chemistry, and the means by which knowledge is transferred from one location to another. I begin with a short discussion of Jack Morrell’s research school concept, and how this has been extended by more recent work. I then discuss Justus Liebig’s school in Giessen, highlighting those aspects of that research school that remain controversial and showing how more recent historical work on training and research in both theoretical and laboratory contexts can usefully be applied to Liebig’s Giessen laboratory. Next, I use the key characteristics of Liebig’s research school that emerge from that analysis as a new standard against which to examine what August Wilhelm Hofmann was expected to re-create when he was brought to London in 1845 to be the fi rst director of the newly founded Royal College of Chemistry (hereafter RCC). Finally, I suggest how the new insights gained from this study may be used to supplement Morrell’s original research school approach in ways that produce a clearer understanding of how successful training and research organizations are created and propagated. Morrell’s celebrated comparison of the schools of Justus Liebig and Thomas Thomson brought the research school concept into prominence as a unit of historical analysis early in the 1970s. His work struck a chord with prevailing themes within the discipline of history of science, and provided a tool with which historians were able to integrate social, cultural, and technical aspects of their fi eld of study. The rapidly professionalizing discipline of nineteenth-century chemistry provided rich material for Morrell’s approach. New substances, especially organic chemicals, were being isolated in increasingly large numbers from natural sources and the study of chemical transformations produced yet more artifi cial compounds. Chemists, most notably Liebig and his associates, attempted to understand the identity of these substances by applying the techniques of quantitative organic analysis to determine their elemental composition. In the period before 1860, the number of well-characterized substances in the chemical literature rose to about 3000, doubling approximately every twenty years. This growing body of knowledge urgently required rationalization in order to remain manageable and the ability to analyse the composition of organic substances accurately and speedily was crucial to that process. This was Liebig’s chosen research goal, achieved by introducing a new method for analysis and increasing the number of people able to apply it, with the result that the Giessen

Reye syndrome after acute enteritis during the neonatal period

Purpose:The prevalence of Reye syndrome has decreased since late 1980's. But we report that recently there were concentrative attacks of Reye syndrome after acute enteritis during the neonatal period. Methods:Clinical symptoms and laboratory results(quantitative organic acid analysis, routine chemistry, arterial blood gas analysis, serum ammonia) of seven patients admitted at the Samsung Medical Center, Sanggye Paik Hospital, Wonju Christian Hospital and Chuncheon Sacred Heart Hospital, referred from Jan. 2005 to Apr. 2005, were analysed retrospectively. The major clinical symptoms were derived from the patients' clinical records sended with urine samples and quantification of organic acids were done with gas chromatography and mass spectrometry. Results:The mean age of seven cases is 18 days and the major preceding symptoms were gastrointestinal symptoms(vomiting, diarrhea, refusal to feeding). The major clinical symptoms were clouded conciousness, repiratory difficulty, vomiting, seizures, and diarrhea. One patient died; that patient's serum ammonia was twenty times higher than normal. Conclusion:The seven patients were neonates. Reye syndrome has been known to be closely related with upper respiratory infections as a preceding disease and to internal use of aspirin, but in our study, the major preceding disease of the seven cases was gastrointestinal infection and none of these used aspirin.

Organic acidemias in Korea - Eight years experience of organic acid analysis -

Purpose:We have done this retrospective study to know the relative incidence and clinical manifestations of organic acidopathies in Korea during 8 years(from Jul. 1997 to May 2005). This results of organic acid analysis of 1,787 patients were compared with the results of organic acid analysis that were published three years ago. Methods:The results of quantitative organic acid analysis of samples of 1788 patients, referred from Jul. 1997 to May 2005, were analyzed retrospectively according to four age group(-2 mon, 3 mon-2 years, 3-12 years) and major clinical manifestations. Quantification of 83 organic acids was done with gas chromatography and mass spectometry. Results:We diagnosed 470 patients with 27 diseases of organic acid metabolism during this study period. Diseases found more than 10 cases are cytosolic 3-ketothiolase deficiency, mitochondrial respiratory chain disorders, PDHC deficiency, mitochondrial 3-ketothiolase deficiency, glutaric aciduria type II, biotinidase deficiency, methylmalonic aciduria and propionic aciduria. Other diseases were diagnosed in less than 10 cases. Conclusion:Though the incidence of individual organic acidemia is low, the overall incidence of organic acidemia as a whole seems to be relatively high in Korea. Compared with the results of organic acid analysis that were reported three years ago, we couldn't find a new disease and the difference of the relative incidences of high incident diseases. We were apprehensive of the errors that was owing to the short study period(3 years), but the relative incidences of our study(8 years) were similar to the results of organic acid analysis that were reported three years ago.

Metabolomic approaches to mitochondrial disease: correlation of urine organic acids

In order to examine correlations which might be useful in ascertaining or confirming the diagnosis of mitochondrial disease, a retrospective analysis of urine organic acids was performed. Among 3646 analyses from randomly selected samples referred to our laboratory, there were 258 specimens from 67 patients with various known disorders of mitochondrial oxidative function, most of whom were known to have chronic and persistent elevations of blood lactic acid, and 176 samples from 21 patients with diagnosed organic acidemia. Urine lactate was not a useful discriminator; only 7.6% of results from infants with mitochondrial disease fell the 95th percentile for patients without mitochondrial disease. Most of the Krebs cycle intermediates were also not useful in discriminating patients with mitochondrial disorders. Interestingly, there was strikingly poor correlation among most of those analytes in all patient groups, but fumarate and malate were uniquely well correlated (r 2=0.840). Fumarate and malate were also the most useful in distinguishing patients with mitochondrial disease and organic acidemia from the pool of unselected or undiagnosed patients, although the utility was somewhat limited. Using a cutoff value of approximately 90 mmol/mol creatinine for fumarate or malate at age <1 year, or a cutoff of approximately 25 for older patients, 25ndash;30% of mitochondrial disease patients can be distinguished with a 5% false positive rate. Further refinements to this approach may better characterize the metabolomic profile and may improve the diagnostic utility of quantitative organic acid analysis in mitochondrial disease.

The Role of Isotope Dilution Mass Spectrometry in the Development of Tandem Mass Spectrometry for Quantitative Organic Analysis

The Role of Isotope Dilution Mass Spectrometry in the Development of Tandem Mass Spectrometry for Quantitative Organic Analysis

The Role of Isotope Dilution Mass Spectrometry in the Development of Tandem Mass Spectrometry for Quantitative Organic Analysis

The Role of Isotope Dilution Mass Spectrometry in the Development of Tandem Mass Spectrometry for Quantitative Organic Analysis

A quantitative organic analysis using carbon magnetic resonance: A study in enamine isomer distribution and relative stabilities

A quantitative organic analysis using carbon magnetic resonance: A study in enamine isomer distribution and relative stabilities

Physiology and pathophysiology of organic acids in cerebrospinal fluid.

Concentrations of organic acids in cerebrospinal fluid (CSF) appear to be directly dependent upon their rate of production in the brain. There is evidence that the net release of short-chain monocarboxylic acids from the brain is a major route for removing these products of cerebral metabolism. Concentrations of organic acids in blood and CSF are largely independent of each other. Quantitative reference values for the concentrations of organic acids in CSF and plasma as well as ratios of individual organic acids between CSF and plasma were determined in 35 pairs of samples from paediatric patients. Over 25 organic acids were quantifiable in all or in the majority of CSF and/or plasma specimens (limit of detection 1 mumol/L). There were substantial differences in the CSF/plasma ratios between subgroups of organic acids. Metabolites related to fatty-acid oxidation were present in CSF in substantially less amounts than in plasma. Organic acids related to carbohydrate and energy metabolism and to amino acid degradation were present in CSF in the same amounts as or slightly smaller amounts than in plasma. Finally, some organic acids were found in substantially higher amounts in CSF than in plasma, e.g. glycolate, glycerate, 2,4-dihydroxybutyrate, citrate and isocitrate. Studies of organic acids in CSF and plasma samples are presented from patients with 'cerebral' lactic acidosis, disorders of propionate and methylmalonate metabolism, glutaryl-CoA dehydrogenase deficiency and L-2-hydroxy-glutaric aciduria. It became apparent that derangements of organic acids in the CSF may occur independently of the systemic metabolism. Quantitative organic acid analysis in CSF will yield new information on the pathophysiology in the central nervous system (CNS) of these disorders and may prove necessary for successful monitoring of treatment of organoacidopathies, which present mainly with neurological disease. For example, in glutaryl-CoA dehydrogenase deficiency the urinary excretion of glutarate appears to be an inadequate parameter for monitoring the effect of dietary therapy, without plasma and CSF determinations. In L-2-hydroxyglutaric aciduria the elevation of L-2-hydroxyglutarate was found to be greater in CSF than in plasma. In addition, some other organic acids, glycolate, glycerate, 2,4-dihydroxybutyrate, citrate and isocitrate, were also elevated in the CSF of the patients out of proportion to normal levels in plasma and urine. High concentrations of an unknown compound, which was tentatively identified as 2,4-dihydroxyglutarate, were found in the CSF of patients with L-2-hydroxyglutaric aciduria.(ABSTRACT TRUNCATED AT 400 WORDS)

Action of activated coke as a catalyst: oxydehydrogenation of ethylbenzene to styrene

Oxidative dehydrogenation of ethylbenzene to styrene has been carried out in an isothermal integral reactor on several samples of alumina having different superficial acidities. Variations in the acidity were achieved by doping of the alumina with sodium and were measured by temperature-programmed desorption (TPD) of ammonia. An active catalytic coke was formed on the alumina during reaction. In order to determine the degree of condensation, crystallinity, and characteristics of the functional groups responsible for the catalytic activity of the active coke, analyses were conducted by oxidation at programmed temperature (TPO), X-ray transmission, and electronic paramagnetic resonance (EPR). Changes in the C/H/O ratio of the coke, estimated by quantitative organic analysis, produce changes in the catalytic activity and in the styrene yield. The evidence of the presence of oxygenated species in the coke and the participation of this oxygen in oxidative dehydrogenation suggested a redox-type reaction mechanism.

Quantification using desorption techniques: A report on the workshop sponsored by the committee for quantitative organic analysis at the 32nd Annual Conference of the American Society for Mass Spectrometry, San Antonio, Texas, May 29, 1984

Quantification using desorption techniques: A report on the workshop sponsored by the committee for quantitative organic analysis at the 32nd Annual Conference of the American Society for Mass Spectrometry, San Antonio, Texas, May 29, 1984

Intercomparison of 11 mass spectrometers applied for quantitative organic analysis in Denmark

Eleven mass spectrometers all connected with a gas chromatograph were used for quantitative determination by the isotopic dilution technique. The purpose of the investigation was to compare the virtual performances of the instruments rather than the routines of the individual laboratories. Therefore, calibration compounds and samples were distributed to the participants. A satisfactory linearity but poor reproducibility was found.

High-resolution carbon-13 solid-state nuclear magnetic resonance spectroscopy

The status of high-resolution carbon-13 solid-state nuclear magnetic resonance (NMR) spectroscopy with respect to quantitative organic analysis is discussed. As the techniques for obtaining NMR spectra from solids are somewhat different from those used in liquid-state NMR, the experimental concepts are outlined first. Spectra that illustrate a few of the topics that have been studied in the author's laboratory are then presented. Finally, the problem of quantitativeness (or indeed non-quantitativeness) of such carbon-13 solidstate NMR spectra is examined.

Report on the workshop sponsored by the committee for quantitative organic analysis at the 27th annual conference of the American society for mass spectrometry, Seattle, Washington, June 1979. Quantitative gas chromatography mass spectrometry—techniques and problems

Report on the workshop sponsored by the committee for quantitative organic analysis at the 27th annual conference of the American society for mass spectrometry, Seattle, Washington, June 1979. Quantitative gas chromatography mass spectrometry—techniques and problems

Quantitative Organic Analysis by Electron Probe: Urea

It is now just 10 years since the first published description of a method for elemental analysis of biological fluids by electron probe (1). During this decade microdroplet analysis techniques have been highly perfected and are in routine use in many laboratories for the study of droplets in the 10 to 100 picoliter (pi) range. Despite this rapid development, droplet analysis remains almost entirely elemental since techniques for molecular characterization by electron probe have not been established. In renal physiology, where microdroplet analysis has been most accepted, single specimens are routinely studied for Na, K, Ca, Mg, Cl, P, and S; but urea, which plays a fundamental role in the mechanism of urine concentration, cannot be directly measured except by wet photometric techniques requiring several nanoliters of fluid and many quantitative handling steps (2, 3). In this report, a new method for droplet analysis is presented which permits electron probe measurement of both urea and elemental concentrations in single 50 pi droplets.

Periodate cleavage of glycols: A quantitative organic analysis experiment

This reaction is much used by organic chemists and uses the familiar standard solutions of iodine and sodium arsenite, common buffers, and stable organic glycols, such as ethylene glycol and pinacol.

Qualitative and quantitative organic analysis: Elementary and functional groups

Qualitative and quantitative organic analysis: Elementary and functional groups

Qualitative and quantitative organic analysis

Qualitative and quantitative organic analysis

Qualitative and quantitative organic analysis. Elementary and functional groups

Qualitative and quantitative organic analysis. Elementary and functional groups