Gas chromatographic determination of isocitric and malic acid in the presence of a large excess of citric acid

Molnár-Perl, I.; Morvai, M.; Pintér-Szakács, M.; Petró‐Turza, M.

doi:10.1016/s0003-2670(00)83849-0

Cited by 10 publications

(4 citation statements)

References 10 publications

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“…The relative standard deviation of the peak area was 4.0% (n = 7) and 2.8% (n = 7) at 1 and 10 µM, respectively. These values seems to be small, compared with that found in the gas chromatographic study, 9) 7.5% in the concentration 1.2 × 10 -3 -9.0 × 10 -3 g isocitrate per 100 g. The 30 times analysis of the isocitrate sample (2 µM) could be accurately carried out in one hour by the present method. And this analysis rate is in contrast to that in the analysis using soluble enzyme 7) in which it takes more than 15 min to analyze a single sample.…”

Section: Resultscontrasting

confidence: 47%

Determination of Isocitrate Using Immobilized Isocitrate Dehydrogenase in a Flow System and its Application to Analyze the Total Isocitrate Content of Beverages

Mori

Okamoto

Fujita

2005

JOURNAL OF HEALTH SCIENCE

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The quantity of isocitrate was determined using an apparatus containing a reactor with immobilized isocitrate dehydrogenase in a flow line. NADH formed by an enzymatic reaction was fluorometrically detected. The optimal concentration of NAD + in the carrier was determined. The maximum peak areas due to NADH were observed at pH 8.0 when the pH of the carrier consisting of Tris buffer ranged from 6.0 to 8.6. Various buffer types were also examined as carrier mediums at pH 8.0. In contrast to 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES), piperazine-1,4-bis(2-ethanesulfonic acid) (PIPES) and triethanolamine buffers which afforded comparable peak areas with that of Tris buffer, phosphate buffer showed a reduced peak area. This peak area decreased with an increase in the pH of the phosphate buffer from 6.5 to 8.5, suggesting the inhibitory effect of phosphate dianions upon the binding of adenosine-5′-monophosphate (AMP) to the binding site of the enzyme. When the carrier composed of Tris buffer (0.1 M, pH 8.0) was used, the calibration curve for isocitrate was linear in the range of 0.1-50 M (r = 1.000). The detection limit (S/N = 3) was 0.07 M. Relative standard deviations of the peak area at 1 and 10 M were 4.0% (n = 7) and 2.8% (n = 7), respectively. Thirty samples of isocitrate (2 M) were analyzed for 1 hr. This method was applied to the analysis of total isocitrate in several beverages. The recovery tests for the isocitrate added to samples indicatied the reliability of the present method.

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Section: Resultscontrasting

confidence: 47%

Determination of Isocitrate Using Immobilized Isocitrate Dehydrogenase in a Flow System and its Application to Analyze the Total Isocitrate Content of Beverages

Mori

Okamoto

Fujita

2005

JOURNAL OF HEALTH SCIENCE

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“…The relative standard deviation of the peak area was 1.5% (n = 7) and 0.36% (n = 7) at 1 µM and 10 µM, respectively. These values seem small compared with that found in the gas chromatographic study, 8) 4.2% in the concentration 4.2 × 10 −3 -3.5 × 10 −2 g malate per 100 g. The 30 analyses of the malate sample (10 µM) could be accurately carried out in 1 hr by this method. This analysis rate is in contrast Values by this method are the averages of quintuplicate determinations.…”

Section: Resultsmentioning

confidence: 56%

“…To evaluate the authenticity of fruit juices, the determination of specific acids, isocitrate and L-malate, which are present in measurable amounts only in genuine juices, was recommended. [8][9][10][11] Thus, this method was applied to determine the content of L-malate in various beverages.…”

Section: Introductionmentioning

confidence: 99%

Determination of L-Malate Using Immobilized Malate Dehydrogenase and Aspartate Aminotransferase in a Flow System and its Application to Analyze the L-Malate Content of Beverages

Mori

Yamashita

Maitani

2007

JOURNAL OF HEALTH SCIENCE

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The quantity of L-malate was determined using apparatus comprised of a reactor with immobilized malate dehydrogenase (MDH) and aspartate aminotransferase (AST) in a flow line. NADH formed by an enzymatic reaction was fluorometrically detected. The optimal concentration of NAD + in the carrier containing 0.1 M glutamate was determined. The maximum peak areas due to NADH were observed at pH 8.0 when the pH of the carrier consisting of Tris buffer ranged from 7.0 to 8.5. Various buffer types were also examined as carrier media at pH 8.0 and Tris buffer showed the maximum peak area. When the carrier composed of Tris buffer (0.1 M, pH 8.0) was used, the calibration curve for malate was linear in the range of 0.05-50 µM (r = 1.000). The detection limit (S/N = 3) was 0.03 µM. Relative standard deviations of the peak area at 1 µM and 10 µM were 1.5% (n = 7) and 0.36% (n = 7), respectively. Thirty samples of malate (10 µM) were analyzed for 1 hr. This method was applied to the analysis of malate in several beverages, and malate content determined by this method agreed with that determined by a commercially available test-kit method.

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“…(i) for reproducible quantitation of high molecular weight compounds (which although highly sensitive to hydrolytic decomposition, need high evaporation temperatures) such as chlorogenic acid (caffeic acid esterified by quinic acid, i.e., 1,3,4…”

Section: Introductionmentioning

confidence: 99%

Simultaneous capillary GC of acids and sugars as their silyl(oxime) derivatives: Quantitation of chlorogenic acid, raffinose, and pectin substances

Tisza

Molnár-Perl

Friedman³

et al. 1996

J. High Resol. Chromatogr.

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SummaryOur GC-MS method for the simultaneous quantitation of sugars and acids as their silyl(oxime) derivatives, from one solution by one injection, has been extended to the reproducible determination of high molecular weight compounds sensitive to decomposition yet requiring a high evaporation temperature (e.g. chlorogenic acid and raffinose) and for the quantitation of the decomposition products of pectin (ie., for the determination of galacturonic acid at low ng levels in the presence of a 10-100 fold excess of glucose eluting just before the acid). The optimized GC procedure has been used for quantitation of the sugar and acid (including chlorogenic acid) composition of potato samples, and for the determination of the increasing amount of the decomposition products of pectin substances in apple pulp after different storage times.

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Gas chromatographic determination of isocitric and malic acid in the presence of a large excess of citric acid

Cited by 10 publications

References 10 publications

Determination of Isocitrate Using Immobilized Isocitrate Dehydrogenase in a Flow System and its Application to Analyze the Total Isocitrate Content of Beverages

Determination of Isocitrate Using Immobilized Isocitrate Dehydrogenase in a Flow System and its Application to Analyze the Total Isocitrate Content of Beverages

Determination of L-Malate Using Immobilized Malate Dehydrogenase and Aspartate Aminotransferase in a Flow System and its Application to Analyze the L-Malate Content of Beverages

Simultaneous capillary GC of acids and sugars as their silyl(oxime) derivatives: Quantitation of chlorogenic acid, raffinose, and pectin substances

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