Tartaric acid, detection

Although no direct tartaric acid detection enzymatic assay is available commercially, tartaric acid can be accessed as a secondary substrate of D-malate dehydrogenase. 

Multiple Chiral Centers. The number of stereoisomers increases rapidly with an increase in the number of chiral centers in a molecule. A molecule possessing two chiral atoms should have four optical isomers, that is, four structures consisting of two pairs of enantiomers. However, if a compound has two chiral centers but both centers have the same four substituents attached, the total number of isomers is three rather than four. One isomer of such a compound is not chiral because it is identical with its mirror image it has an internal mirror plane. This is an example of a diaster-eomer. The achiral structure is denoted as a meso compound. Diastereomers have different physical and chemical properties from the optically active enantiomers. Recognition of a plane of symmetry is usually the easiest way to detect a meso compound. The stereoisomers of tartaric acid are examples of compounds with multiple chiral centers (see Fig. 1.14), and one of its isomers is a meso compound. 

Even before heating all the acids rapidly appeared as blue zones on a yellow-blue background. After heating tartaric acid QiRf 2—5) and maUc acid hRf 5 — 10) retained their color while lactic acid hRf 30 — 35), succinic acid hRf 35—40), pimelic acid hRf 50), maleic acid hRf 55), suberic acid hRf 55 — 60), benzoic acid hRf 80 — 85), stearic acid hRf 85 — 90) and arachidic acid hRf 85—90) appeared as pale yellow zones on a blue-yellow background (Fig. 1). The detection limits lay at 1 to 2 pg substance per chromatogram zone. 

Simultaneous determination of both cations and anions in acid rain has been achieved using a portable conductimetric ion-exclusion cation-exchange chromatographic analyzer.14 This system utilized the poly(meth-ylmethacrylate)-based weak acid cation exchange resin TSK-Gel OA-PAK-A, (Tosoh , Tokyo, Japan) with an eluent of tartaric acid-methanol-water. All of the desired species, 3 anions and 5 cations, were separated in less than 30 minutes detection limits were on the order of 10 ppb. Simultaneous determination of nitrate, phosphate, and ammonium ions in wastewater has been reported utilizing isocratic IEC followed by sequential flow injection analysis.9 The ammonium cations were detected by colorimetry, while the anions were measured by conductivity. These determinations could be done with a single injection and the run time was under 9 minutes. 

The results obtained appeared quite promising, but the real sensation was the detection of pyruvate, the salt of 2-oxopropanoic acid (pyruvic acid), which is one of the most important substances in contemporary metabolism. Pyruvic acid was first obtained in 1835 by Berzelius from dry distillation of tartaric acid. The labile pyruvate was detected in a reaction mixture containing pure FeS, 1-nonanethiol and formic acid, using simulated hydrothermal conditions (523 K, 200 MPa). The pyruvate yield, 0.7%, was certainly not overwhelming, but still remarkable under the extreme conditions used, and its formation supports Wachtershauser s theory. Cody concludes from these results that life first evolved in a metabolic system prior to the development of replication processes. 

Surface modification of skeletal nickel with tartaric acid produced catalysts capable of enantiose-lective hydrogenation [85-89], The modification was carried out after the formation of the skeletal nickel catalyst and involved adsorption of tartaric acid on the surface of the nickel. Reaction conditions strongly influenced the enantioselectivity of the catalyst. Both Ni° and Ni2+ have been detected on the modified surface [89]. This technique has already been expanded to other modified skeletal catalysts for example, modification with oxazaborolidine compounds for reduction of ketones to chiral alcohols [90],... 

Figure 4.7 Anion exchange separation of carboxylic acids in red wine. Column, Shodex C811, 100 cm x 7.6 mm i.d. eluent, 3 mM perchloric acid flow rate, 0.9 ml min-1 temperature, 60 °C detection, reaction detection using chloro-phenol red at 430 nm. Peaks 1, citric acid 2, tartaric acid 3, malic acid 4, succinic acid 5, lactic acid 6, formic acid and 1, acetic acid.

The measurement of stability constants of complexes of yttrium, lanthanide, and actinide ions with oxalate, citrate, edta, and 1,2-diaminocyclohexanetetra-acetate ligands has revealed that there is a slight increase in the stability of complexes of the /-electron elements, relative to the others. A series of citric acid (H cit) complexes of the lanthanides have been investigated by ion-exchange methods and the species [Ln(H2cit)]", [Ln(H2cit)2] , [Ln-(Hcit)], and [Ln(Hcit))2] were detected. Simple and mixed complexes of dl- and jeso-tartaric acid have been obtained with La " and Nd ions, and the stability constants of lactate, pyruvate, and x-alaninate complexes of Eu and Am " in water have been determined. 

In another work, Parra and coworkers proposed a method based on chemically modified voltammetric electrodes for the identification of adulterations made in wine samples, by addition of a number of forbidden adulterants frequently used in the wine industry to improve the organoleptic characteristics of wines, like, for example, tartaric acid, tannic acid, sucrose, and acetaldehyde (Parra et ah, 2006b). The patterns identified via PCA allowed an efficient detection of the wine samples that had been artificially modified. In the same study, PLS regression was applied for a quantitative prediction of the substances added. Model performances were evaluated by means of a cross-validation procedure. 

Regarding the detection of tartaric acid in citric acid see Merck s Reagentien-Verzeichnis (1903), p. 170 A. I. Cohn, Tests and Reagents (1903), pp. 40, 51, 242. 

Tartrate Ammonium tartrate [CAS 3164-29-2] (NH4)2C4kLOb. white solid, moderately soluble, formed by reaction of NH4OH and tartaric acid, and then evaporating. Used in the textile industry ammonium hydrogen tartrate, ammonium bitartrate, ammonium acid tartrate NH4HC4H4CX , white solid, slightly soluble, formation sometimes used in detection of ammonium or tartrate. 

Fig. 2 Separation on two cation-exchange columns connected in series of the dry wine standard using 0.065% H3P04 at a flow rate of 0.7 ml/min and detected by RI. 1—citric acid, 0.5 g/L 2—tartaric acid,...

The detection threshold for MSG was as low as 0.012 g/lOOml or 6.25 x 10 M. It was higher than that of quinine sulfate or tartaric acid, lower than that of sucrose and almost the same as that of sodium chloride in the molar concentration. Some umami substances have lower thresholds than that of MSG. 

Kappes et al. evaluated the potentiometric detection of acetylcholine and other neurotransmitters through capillary electrophoresis [209]. Experiments were performed on an in-house capillary electrophoresis instrument that made use of detection at a platinum wire, dip-coated in 3.4% potassium tetrakis (4-chlorophenyl) borate/64.4% o-nitrohenyl octyl ether/32.2% PVC in THF. The results were compared to those obtained using capillary electrophoresis with amperometric detection at a graphite electrode. Samples prepared in the capillary electrophoresis buffer were electrokinetically injected (7 s at 5 kV) into an untreated fused silica capillary (88 cm x 25 pm i.d.) and separated with 20mM tartaric acid adjusted to pH 3 with MgO as the running buffer. The system used an applied potential of 30 kV, and detection versus the capillary electrophoresis ground electrode. 

Arsenates and silicates with ammonium molybdate yield the ammonium salts of arsenomolybdic, H3[AsMo12O40] or H3[As(Mo3O10)4], and silico-molybdic, H4[SiMo12O40] or H4[Si(Mo3O10)4], acids respectively these complex acids and their salts react similarly with benzidine. However, phosphates may be detected in the presence of arsenates and silicates by preventing the formation of the corresponding molybdo-acids by the use of a tartaric acid-ammonium molybdate reagent which does not react with arsenic and silicic acids but does react with phosphoric acid when the reaction is carried out on filter paper. 

Fig. 3. HPLC chromatograms of cell liquid in Mackaya cordata root. Column NOVA-pack C g (5p.), 8 mm x 10 cm eluent 0.1 iV tartaric acid (containing 0.125% sodium dodecyl sulfate)— acetonitrile, 45 55 at 2.0 ml/min detection UV, 285 nm. (a) Alkaloid (colored) cell, (b) Colorless cell. Peaks a, protopine b, allocryptopine c, sanguinarine d, chelerythrine.

The palladium(II)-catalyzed [3,3] sigmatropic rearrangement of the (4.S ,5.S )-diacetate, derived from tartaric acid (entry ll)21 produced only the conjugated (2/ ,7R)-diacetate the other possible conjugated (25,35)-diacetoxy-4,6-diene derivative was not detected. 

If an excess of hydrogen peroxide be added to a solution containing a chromate, made slightly acid with sulphuric acid, and the mixture then shaken up with a few c.c. of ether, a blue ethereal layer is formed above the aqueous solution. The colour is due to the formation of perehromie acid (see p. 73), and the reaction aSords a usefiil test for identifying chromates in presence of sulphuric acid. If the ether used is free from alcohol, 1 part of potassium chromate in 40,000 parts of water can be detected. Another sensitive test for chromates and di-ehromates is to add a trace of a-naphthylamine to the solution and acidify with tartaric acid, when an intense blue colour results. ... 

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