Glyoxylic acid detection

Glyoxylic acid solution (protein detection) cover 10 g of magnesium powder with water and slowly add 250 mL of a saturated oxalic solution, keeping the mixture cool filter off the magnesium oxalate, acidify the filtrate with acetic acid and make up to a liter with water. 

With a 1 1 molar ratio of ethylene glycol and H2O2, the selectivity to glycolic acid was 86% at 44% conversion of the glycol and 99% conversion of the H202. Small amounts of glyoxylic acid (3%) and formic acid were also detected. 

Similar processes have been observed with other aldehydes, such as glyoxylic acid. However, the carboxymethine-linked oligomers resulting from reaction with glyoxylic acid proceeded to xanthylium salts rather than to larger polymers (Es-Safi et al. 1999b). The postulated pathway involves dehydration and cyclisation of the carboxymethine dimer (Eig. 9B.6(4)) followed by oxidation of the resulting xanthene (Eig. 9B.6(5)) that was also detected in the medium. Formation of xanthylium salts was also shown in the case of furfural and hydroxymethylfurfural (Es-Safi et al. 2000). 

The reaction was performed under the fixed reaction conditions described in the Experimental section, while changing the contact time from 0.3 to 5.0 s. The main products detected were glyoxylic acid, formaldehyde, formic acid, and carbon oxides. The yields of these products are plotted as a function of the conversion of glycolic acid in Figure 1. The slope of lines from the origin indicate the selectivities to each product. 

Figure 1 Example of colorless adducts and colored purple pigments detected in model solution containing (-fepicatechin (Rj= H, R2= OH) or (+)-catechin (Rj- OH, R2= H), malvidin 3-0-glucoside and acetaldehyde (R= CH3), glyoxylic acid (R= COOH), furfural (R-furyl group),...

The mechanism postulated above for xanthylium salts formation was also found to occur more generally. Thus yellow xanthylium salts showing absorption maxima at 440 nm were detected when glyoxylic acid was replaced by furfural and HMF. Using LC/ESI-MS chromatography these confounds were detected at m/z 637 and 667 amu for furfural and HNff respectively. The corresponding... 

White observed a post-irradiation process between glyoxylic acid and hydrogen peroxide in irradiated glycine solutions. Synthetic mixtures of these two compounds reacted similarly, to give equivalent amounts of formic acid, and Hatcher and Holden have shown that reaction (3) is bimolecular no oxalic acid can be detected, and the sodium salt is particu-... 

Glyoxylic Acid. Trace amounts of glyoxylic add have been detected by some workers in normal blood and/or urine (B18, H19, Kl, VI, Z2), whereas others did not find it on normal chromatograms of... 

In the presence of oxygen, the following products (G values in units of 10 mol j in parentheses) were observed after y-radiolysis formaldehyde (1.6), CO2 (1.6), glyoxylic acid (4.2), iminodiacetic acid (2.1), ethylenediaminetri-acetic acid (detected, not quantified). 

The transamination of asparagine in soybean leaf extracts was detected by Streeter (1977). Glyoxylic acid was the most active 2-oxo acid acceptor, followed by pyruvate, oxaloacetate, and 2-oxoglutarate. The breakdown of the product 2-oxosuccinamic acid to oxaloacetate and ammonia was also detected. 

Gold catalyzed oxidations of alcohols and diols possess great potential towards selectivity [10]. As example, chemical kinetics was measured during the catalytic oxidation of ethylene glycol based on the O2 consumptiom Deposited Au on the porous glass shows no catalytic activity while the Au loaded ceria replica shows an initial activity of 53 mmol-gAu min within the first 10 minutes of the reaction. In the latter case, after 60 minutes a conversion of 59% was obtained. As main prodnct glycolic acid was produced at a selectivity of 94%. Oxalic acid and glyoxylic acid were detected as side products. 

In alkaline media, the complex [Ni(edta)] reacts with CO7 to give an adduct which aquates to the nickel(III) transient [Ni(edta)(H20)] with a first-order rate constant of 1.1 x 10 s . [Ni(edta)(H20)], which is a powerful oxidant, decays by formation of a ligand radical and reaction with [Ni(edta)] yielding glyoxylic acid and formaldehyde. Oxidation of edta by [Mn04] leads to the formation of CO2 and l,2-diaminoethane-W,W, A-triacetic acid (edtri), Eq. (22). An intermediate complex absorbing at 418 nm is detected. The triplet excited state, [ Pt2(/i->/ -H2P20j)4] ,... 

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