University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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l-Malic acid

  • IUPAC Name: (2S)-2-hydroxybutanedioic acid
  • Molecular Formula: C4H6O5
  • CAS Registry Number: 97-67-6
  • InChI: InChI=1S/C4H6O5/c5-2(4(8)9)1-3(6)7/h2,5H,1H2,(H,6,7)(H,8,9)/t2-/m0/s1
  • InChI Key: BJEPYKJPYRNKOW-REOHCLBHSA-N

@ ChemSpider@ NIST@ PubChem

Citations 13

"Sheath-flow Fourier Transform Infrared Spectrometry For The Simultaneous Determination Of Citric, Malic And Tartaric Acids In Soft Drinks"
Anal. Chim. Acta 2000 Volume 417, Issue 1 Pages 41-50
María José Ayora-Cañada and Bernhard Lendl

Abstract: A new approach for the determination of organic acids in soft drinks based on pH modulation and Fourier transform infrared spectroscopic detection is presented. The analytical readout was taken from the spectral changes induced by the pH change of the sample. The pH modulation was carried out in a novel sheath-flow cell which was connected to a sequential injection analysis system. The sheath-flow cell comprised three stream lines flowing adjacent to each other in a strongly laminar fashion, The sample (pH similar to 9) was introduced in the central channel whereas reagent (hydrochloric acid) was introduced in the outer channels. As a consequence of the laminar flow profile, hardly any mixing between the stream lines was observed while maintaining the flow, hence allowing the measurement of the sample spectrum at alkaline pH (similar to 9). Upon stopping the flow, diffusion of protons from the outer stream lines into the central line occurred resulting in a complete protonation of the analyte (pH similar to 2). The spectral changes were calculated and the region between 1400 and 1180 cm-1 used to set-up a partial least squares (PLS) calibration model. For the PLS model only standards containing the analytes but no matrix molecules were used. By evaluation of the spectral changes induced by the pH modulation the PLS model could successfully be applied to test samples containing sugars as well as to natural soft drinks.
Soft drink Spectrophotometry Sequential injection Sheath flow Partial least squares Stopped-flow

"Sequential Injection Fourier Transform Infrared Spectroscopy For The Simultaneous Determination Of Organic Acids And Sugars In Soft Drinks Employing Automated Solid Phase Extraction"
Anal. Chim. Acta 2000 Volume 422, Issue 1 Pages 63-69
Hai LeThanh and Bernhard Lendl

Abstract: A fully automated method for the rapid determination of organic acids (citric-, malic- and tartaric acid) and sugars (glucose, fructose, and sucrose) in soft drinks by sequential injection Fourier transform infrared (FTIR) spectroscopy is presented. A convective interaction media (CIM) disc carrying quaternary amino moieties was added as a solid phase extraction column to the flow system. Upon injection of a sample the organic acids were completely retained on the CIM disc whereas sugars passed to the flow cell. The organic acids were subsequently eluted by injection of an alkaline (pH 8.5) 1 M sodium chloride solution and recorded in their fully deprotonated form as a second flow injection peak. In both cases, the FTIR spectra corresponding to the peak maxima were selected for data evaluation. Two partial least squares models, one for sugars and the other for organic acids, were constructed based on the analysis of standards containing all six analytes. The developed method was applied to natural samples yielding results which were in good agreement with those obtained by an external reference method (enzymatic test kits). Deviations in the results were 3.4. and 4.1% for citric and malic acid and ranged from 4.7-5.1% for the sugars. The developed method is characterized by its short analysis time, experimental simplicity and its potential applications in routine analysis and process control.
Soft drink Spectrophotometry Sequential injection Preconcentration Method comparison Solid phase extraction

"Enzymatic Determination Of Free L-(levo)-malic Acid In Must And Wine By Stopped-flow Flow Injection Analysis"
Anal. Chim. Acta 1991 Volume 247, Issue 1 Pages 61-66
C. Garcia De María, T. Manzano Muñoz and A. Alonso Mateos, L. García De María

Abstract: Flow injection/stopped-flow procedures are described for the determination of free L-(-)-malic acid based on the catalytic activity of malate dehydrogenase. Malic acid concentrations higher than 7.5 times 10^-7 M can be determined with a sampling frequency of 80 h-1. The proposed procedures were applied to the determination of the L-(-)-malic acid content in samples of different types of wine and must undergoing malolactic fermentation.
Must Wine Spectrophotometry Stopped-flow Catalysis

"Enzymic Determination Of L(+) Lactic And L(-) Malic Acids In Wines By Flow Injection Spectrophotometry"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 187-191
José L. F. C. Limaa, Teresa I. M. S. Lopesb and António O. S. S. Rangelb,*

Abstract: A flow injection system for the enzymatic determination of L(+) lactic acid and L(-) malic acid in wines with spectrophotometric detection is described. The samples are dialyzed inline, and the enzymes in solution (malate dehydrogenase and lactate dehydrogenase) are injected as a train of plugs in the acceptor stream of the dialysis unit, yielding two peaks corresponding to the NADH formed for each determination This methodology enables the determination of both acids with a single detector with a sampling rate of 20 h-1 (0.4-3 g L-1). The results are comparable to those obtained by the reference procedure, the repeatability is better than 5% (rsd), with low enzyme consumption (1.3 µL of suspension per sample).
Wine Spectrophotometry Enzyme Method comparison

"Amperometric Determination Of L-malic Acid In A Flow Injection Analysis Manifold Using Packed-bed Enzyme Reactors"
Analyst 1996 Volume 121, Issue 4 Pages 435-439
Mamas I. Prodromidis, Stella M. Tzouwara-Karayanni, Miltiades I. Karayannis, Pankaj Vadgama and Andrew Maines

Abstract: The sample (130 µL) was injected into a carrier stream (0.19 ml/min) of 0.05 M glycylglycine buffer of pH 9.5 (buffer A) containing 1.75 mM hexacyanoferrate(III) and merged with a reagent stream (0.14 ml/min) of 9.5 mM NAD+ in buffer A. The mixture was passed through a packed-bed reactor (3 cm x 2 mm i.d.) containing malate dehydrogenase and diaphorase co-immobilized on isothiocyanate-modified controlled-pore glass (preparation described). The hexacyanoferrate(II) produced was monitored amperometrically at a graphite electrode held at +0.3 V vs. Ag/AgCl. The calibration graph was linear for 20-400 µM malate, the detection limit was 1 µM and the RSD (n = 5) at the 100 µM malate level was 1.2%. The throughput was 30 samples/h. The method was applied to fruits and vegetables. Recoveries of malate were 95-108%. The results obtained agreed with those obtained by an enzymatic test-kit method.
Fruit Vegetable Amperometry Controlled pore glass

"A Rapid Automated Method For Wine Analysis Based Upon Sequential Injection (SI)-FTIR Spectrometry"
Fresenius J. Anal. Chem. 1998 Volume 362, Issue 1 Pages 130-136
R. Schindler, R. Vonach, B. Lendl, R. Kellner

Abstract: A new process control methodology for the simultaneous determination of sugars, alcohols, and organic acids in wine based on multivariate evaluation of mid-IR transmission spectra of wine samples is presented. In addition to EtOH several lower level wine components (glucose, fructose, glycerol, citric- , tartaric-, malic-, lactic-, and acetic acid) were determined To establish a multivariate calibration model a set of 72 calibration solutions was prepared and measured, using a novel, fully automated sequential injection (SI) system with Fourier transform IR (FTIR) detection. The resulting spectra were evaluated using a partial least square (PLS) model. The developed PLS model was then applied to the anal. of real wine samples containing 79-91 g L-1 EtOH, 5.9-8.1 g L-1 glycerol, 0.4-6.9 g L-1 glucose, 1.5-7.5 g L-1 fructose, 0.3-1.6 g L-1 citric acid, 1.0-1.7 g L-1 tartaric acid, 0.02-3.2 g L-1 malic acid, 0.4-2.8 g L-1 lactic acid, and 0.15-0.60 g L-1 acetic acid, yielding results which were in good agreement with those obtained by an external reference method (HPLC-IR). The short analysis time (<3 min) together with high reproducibility makes the newly developed method applicable to process control and screening purposes (av. of the standard deviations calculated from four repetitive measurements of 6 different real samples: EtOH: 0.55 g L-1, glycerol: 0.037 g L-1, glucose: 0.056 g L-1, fructose: 0.036 g L-1, citric acid: 0.020 g L-1, tartaric acid: 0.010 g L-1, malic acid: 0.052 g L-1, lactic acid: 0.012 g L-1, and acetic acid: 0.026 g L-1).
Wine Spectrophotometry Sequential injection Method comparison Simultaneous analysis Multivariate calibration Partial least squares

"Determination Of 2-oxo- And Hydroxy-acids By High Performance Liquid Chromatography Using Ferric Perchlorate As A Detection Reagent"
Anal. Sci. 1985 Volume 1, Issue 3 Pages 281-284
S. TANABE, T. TOIDA, T. KAWANISHI, T. TOGAWA and T. IMANARI

Abstract: Oxaloacetic, 2-oxoglutaric, lactic, tartaric, citric, malic, 3-hydroxybutyric and oxalic acids were determined on a cation-exchange column (30 cm x 8 mm) of Shimadzu gel SCR-101H (10 µm) with a guard column (5 cm x 4 mm) of TSKgel SCX (6 µm) and a mobile phase (0.4 mL min-1) of 8 mM HClO4. Post-column derivatization of the acids with use of 9 mM Fe(ClO4)3 - 12 mM HClO4 was then carried out before detection at 380 nm. The method was applied to the determination of pyruvic and lactic acids in blood.
Blood HPLC Spectrophotometry Post-column derivatization

"Microbial Sensor For Estimating Organic-acids In Wine"
Anal. Sci. 1995 Volume 11, Issue 6 Pages 941-945
H. UKEDA, N. YAMAMOTO, M. SAWAMURA and H. KUSUNOSE

Abstract: A microbial sensor based on an oxygen electrode and the microorganism Pseudomonas putida was developed in order to determine fixed acids, such as L-malic acid, succinic acid and L-lactic acid, in wine. The carbon source used in cultivating the microorganism affected the selectivity of the sensor to a great extent. When L-lactic acid was used as the carbon source, the microbial sensor gave a selective response for L-lactic acid. determining L-lactic acid was constructed and applied to commercially available wine samples. The obtained result was a flow injection analysis system for determining L-lactic acid was constructed and applied to commercially available wine samples. The obtained result was comparable to that obtained by the F-kit method. On the other hand, the microbial sensor showed a response for L-malic acid, L-lactic acid, succinic acid and ethanol present in wine when meso-tartaric acid was used in the cultivation. The addition of L-lactic acid (0.05 mM) and ethanol (0.01%) into the carrier solution suppressed the response for L-lactic acid and ethanol, and under the conditions the microbial sensor was thus selective for L-malic acid and succinic acid. The sensor responses for wine samples (n = 6) were linearly related to the sum of the L-malic acid and succinic acid concentrations determined by HPLC with a correlation coefficient of 0.969. (12 references)
Wine Electrode Sensor Immobilized cell Method comparison Interferences

"Enzymatic Determination Of L(-)malic And L(+)lactic Acids In Wine By Flow Injection Analysis"
Am. J. Enol. Vitic. 1992 Volume 43, Issue 1 Pages 58-62
Jos&Eacute; L. F. C. Lima and Ant&oacute;nio O. S. S. Rangel

Abstract: The enzymatic determination of L-(-)-malic and L(+)lactic acids in several types of wines by flow injection analysis (FIA) with spectrophotometric detection is described. This flow injection system, which incorporates a dialysis unit for adjusting the composition of the injected solutions to the requirements of the measuring system, enables determinations of these two organic acids without the need for any prior treatment of the wine samples, with a concentration. interval of between 0.02 and 4 g/L, and a sampling rate of approximately 20 determinations per h. The results obtained with this FIA method for various types of Portuguese wines are in good agreement with those of the batch method which uses the same enzymatic technique and are quite precise as they present a coefficient of variation below 2.5%.
Wine Spectrophotometry Dialysis Method comparison Enzyme

"Continuous-flow Automation Of The Enzymic Determination Of Malic Acid In Wines"
Connaiss. Vigne Vin 1980 Volume 14, Issue 4 Pages 207-217
Aline LONVAUD-FUNEL, B. DONECH, D. BLEUZE

Abstract: Malic acid [6915-15-7] in wine was determined by a continuous enzymatic process that produced NADH. The NADH was used to reduce 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (I) [298-93-1] to the corresponding formazan derivative (II) [57360-69-7]. The transfer of H from NADH to I was accomplished with Meldola Blue. The amt. of II formed was determined by spectrometry at 570 nm.
Wine Spectrophotometry Enzyme

"Simultaneous Enzymic Determination Of L-(.minus.)-malic Acid And L-(+)-lactic Acid In Wine By Flow Injection Analysis"
Food Chem. 1991 Volume 42, Issue 2 Pages 167-182
R. Puchades, M. A. Herrero, A. Maquieira and J. Atienza

Abstract: Online dialyzed samples (80 µL) were injected into the carrier stream [0.05 M carbonate - bicarbonate buffer (pH 9.7) containing 1.5 mM NAD+ and 1 mM EDTA; flow rate 1 mL min-1], which then split into three. One channel (length 64 cm) contained a blank reactor, and the second and third channels (lengths 95 and 185 cm, respectively) contained open tubular glass column reactors (8 cm x 1.2 mm) respectively packed with L-malate dehydrogenase and L-lactate dehydrogenase covalently immobilized on alkylamine glass beads. The flows then converged before reaching the detector flow cell, where the fluorescence intensity of the NADH produced by the enzyme-catalyzed oxidation of L-(-)-malic and L-(+)-lactic acid (I and II, respectively) was measured at 450 nm (excitation at 340 nm). The different dimensions of the three channels provided different residence times, giving three peaks, the first being due to matrix fluorescence. The calibration graphs were rectilinear from 0.1 to 5 mM and from 0.05 to 3 mM for I and II, respectively. Tartaric acid, fructose and SO2 did not interfere. The method was applied to the analysis of 20 commercially available wines. The results agreed with those obtained by HPLC.
Wine Fluorescence Buffer Catalysis EDTA Glass beads Immobilized enzyme Interferences Reactor

"Flow Injection Determination Of Mailc Acid And Dopa Using An Apple Tissue Reactor"
J. Flow Injection Anal. 1995 Volume 12, Issue 1 Pages 91-97
Hideki Horie and Garry A. Rechnitz

Abstract: A reactor containing apple fruit tissue was used for flow injection measurements of both L-malic acid and L-Dopa. Malic acid was determined by the fluorescence of NADPH generated by the action of malate-dehydrogenase in the tissue. Dopa was determined from the red color generated by polyphenol oxidase in the same tissue. The linear measurement ranges were 0.5-20 mM and 5-100 µM for malic acid and Dopa, respectively.

"Electrochemical Biosensors For Assays Of L-Malic And D-Lactic Acids In Wines"
Am. J. Enol. Vitic. 1996 Volume 47, Issue 1 Pages 11-16
M. Gilis, H. Durliat, and M. Comtat

Abstract: The knowledge of L-malic acid concentration is important for the follow-up of grape maturation and of malolactic fermentation; in the same way, D- lactic acid concentration gives information about the growth of lactic piqûre. A simple and inexpensive assay method is proposed with the use of amperometric biosensors developed for this specific application. The results are compared to those obtained with the enzymatic spectrophotometric method (Boehringer kit). The difference between the two measurement results shows that colored substances interfere with the compounds assayed in the case of red wine. To minimize this effect, two methods are proposed: a differential measurement or the addition of charcoal to the sample for the adsorption of colored substances. The short response time allows analysis of 100 samples every day, and the biosensor can work for one month with the same enzymatic solution.
Wine Biotechnology Sensor Sensor Spectroelectrochemistry Electrode Low cost