DNPH 2,4-Dinitrophenylhydrazine

In addition, the DNPH (2,4-dinitrophenylhydrazine) [38] and NADH (dihydronicotinamide adenine dinucleotide) [36] studies with purified Iso-4 provided the evidence that the 70 Da moiety was a pyruvate derivative (C3H2O2). In the DNPH study, treatment of Iso-4 with acid and 2,4-dinitrophenylhydrazine produced the 2,4-dinitrophenylhydrazone of the pyruvic acid liberated from Iso-4. In the NADH study, the amount of NAD+... 

CTA = chromotropic acid DNPH = 2,4-dinitrophenylhydrazine EDTA = ethylene diaminetetraacetic acid FIA = flow injection analysis GC = gas chromatography ... 

Obs LODs refer to each single aldehyde, not the derivative DNPH, 2,4-dinitrophenylhydrazine DNSH, 5-dimethylaminonaphthalene- 1-sulfohydrazide HBA, 4-hydrazinobenzoic acid MBTH, 5... 

Aldehydes, ketones Apply sample solution and moisten with 2 N 2,4-dinitrophenylhydrazine in acetic acid After reacting, dry and chromatograph the 2,4-DNPH derivatives [14]... 

The O-ECAT reagent is a superior alternative to the use of 2,4-dinitrophenylhydrazine (DNPH Chapter 1, Section 1.1) in the study of protein oxidation. DNPH modification produces detectable complexes, but it does not provide information as to what amino acids are involved. O-ECAT modifies carbonyl end products of protein oxidation and in addition, it can provide exact information as to the amino acids that were oxidized. Mass spec analysis of modified proteins performed after proteolysis gives the exact amino acid sequences including the sites of O-ECAT reagent modification. The same antibody that is specific for the metal chelate portion of the standard ECAT reagent also can be used to capture and detect the O-ECAT... 

Carbonyl compounds for instance can be trapped by absorption in a reagent solution containing 2, 4-dinitrophenylhydrazine and hydrogen chloride. Details of this method are extensively described elsewhere (8). The principle of the method is that the carbonyl compounds, in case of rendering plant emission the aldehydes, react with the 2,4-dinitrophenylhydrazine and form 2,4-dinitrophenylhydrazones (2,4-DNPH s) according to the scheme. 

Figure 4.7 — Absorption spectra of 2,4-dinitrophenylhydrazine (2,4-DNPH), 4-nitrophenylhydrazine (4-NPH) and 2-nitrophenylhydrazine (2-NPH) in solution (solid line) and retained on C bonded silica of 60-100 nm particle size (broken line). TTie dotted line corresponds to the blank spectrum in the second type of experiment (cell packed with C,j bonded silica in distilled water). (Reproduced from [97] with permission of Elsevier Science Publishers).

In addition to the spectroscopic methods, there are a number of derivatization methods, in which a derivative of the carbonyl compound that can be easily separated and measured is formed. The most common of these is the use of 2,4-dinitrophenylhydrazine (DNPH), which reacts to form the hydrazone ... 

The dinitrophenylhydrazine (DNPH) assay detects a-keto acids in the urine [1, 4]. 

Figure D2.4.2 Development of the quinoidal ion from the reaction of 2,4-dinitrophenylhydrazine (DNPH) with an aldehyde or ketone. Adapted from Meyer and Rebrovic (1995) with permission from AOCS Press.

Digestibility, protein quality analysis in vitro, 131, 134, 136-139 in vivo, 127-128, 136-139 Dilatometry, to measure fat, 571 -572 Dimethyl sulfoxide (DMSO), plant cell wall, isolation, 706, 708 2,4-Dinitrophenylhydrazine (DNPH), determination of carbonyl compounds, 553-554, 558 (fig.) Diphenol oxidases inhibitors, 392... 

DNPH. see 2,4-Dinitrophenylhydrazine DOPA, conversion of, 395 Dough, washing, starch isolation, 675-676 DPH. see 1,6-Diphenyl-1,3,5-hexatriene Drip loss in solid foods, 319, 321-322. see also Water retention Droplet concentration in emulsions, 516, 594-596... 

Liquid absorption is a common technique for enriching compounds in reactive liquids like solutions of dinitrophenylhydrazine (DNPH) (for aldehydes), acetyl acetone (for formaldehyde) or aqueous carbonate solutions (for organic acids), both procedures which combine trapping and derivatization of the target compound. Another possibility is the use of dissolved alkali or acids to trap certain substances by the formation of salts in the solution. 

Aqueous samples buffered with citrate and pH adjusted to 3. Acidified sample derivatized with 2,4-dinitrophenylhydrazine (DNPH) derivative analyzed by GC-NPD or reverse phase HPLC with UV detection at 360 nm. 

Trace acetone in water may be determined by a fast HPLC method (Takami et al., 1985) aqueous sample passed through a cartridge packed with a moderately sulfonated cation-exchange resin charged with 2,4-dinitrophenylhydrazine (DNPH) DNPH derivative eluted with acetonitrile and analyzed by HPLC with a 3-mm ODS column. 

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