Identification of acids

Rationalize the properties of the oxides and oxoacids of the nonmetals in terms of the oxidation number of the nonmetal and the identification of acid anhydrides. 

In an acid-base reaction, a proton (H ) is transferred from one chemicai species to another. A species that donates a proton is an acid, and a species that accepts a proton is a base. This identification of acids and bases is the Bronsted-Lowry definition of acid-base reactions. From this perspective, every acid-base reaction has two reactants, an acid and a base. Every acid-base reaction aiso forms two products ... 

Hu, J., Reyes-Cruz, G., Chen, W., Jacobson, K. A., and Spiegel, A. M. (2002) Identification of acidic residues in the extracellular loops of the seven-transmembrane domain of the human Ca2+ receptor critical for response to Ca2+ and a positive allosteric modulator. J. Biol. Chem. 277,46622-46631. 

Kopping JT, Patten TE (2008) Identification of acidic phosphorus-containing ligands involved in the surface chemistry of CdSe nanoparticles prepared in tri-n-octylphosphine oxide solvents. J Am Chem Soc 130 5689-5698... 

T. Yamaguchi, T. Jin, T. Ishida, and K. Tnabe, Structural identification of acid sites of suUur-promoted solid super acid and construction of its structure on siUca support,Mate/ Chem. Phys. 17, 3-19 (1987). 

Esters, simple, identification of acidic components, 393, 1063, 1064 identification of alcohol component, 393, 1063, 1064 ... 

Identification of Acids. If plasticizers are saponified by means of alcoholic patassium hydroxide, the potassium salts of most of the carboxylic acids precipitate... 

It seems that the negative charges can also be on a peptide chain. Fujimaki describes the bitter masking action of peptides rich in glutamyl residues (29 ) and the isolation and identification of acidic oligopeptides from a flavour-intensifying fraction from fish protein hydrolysate (30). 

Noguchi, M., Arai, S., Yamashita, M., Kato, H., and Fujimaki, M. 1975. Isolation and identification of acidic oligopeptides occurring in a flavor potentiating fraction from a fish protein hydrolysate. J. Agric. Food Chem. 23, 49-53. 

Lanthanides substitution in proteins also provide structural and functional aspects of proteins. The techniques which provide such useful information are NMR and luminescence techniques. NMR helps assignment of peaks and also provides conformational analysis (i.e.) in identification of acid residues in the vicinity of the binding site. A useful situation arises when the lanthanum binding site is in proximity to the active site. Luminescence spectroscopy gives the number of water molecules bound and also the interionic distance in cases where two binding sites are present. 

Czajkowski, C., Karlin, A., 1995. Structure of the nicotinic receptor acetylcholine-binding site. Identification of acidic residues in the 8 subunit within 0.9 nm of the a subunit-binding site disulfide. J. Biol. Chem. 270, 3160-3164. 

Fig. 5.5 Progressive identification of acids and anhydrides in roasted coffee volatiles...

Gautschi F. (1958) Identification of acids from coffee. Nouveaux Laboratories de Recherche, Firmenich Cie, Geneve, 28-9. 

Mattow, 1., Jungblut, P.R., Muller, E.C., and Kaufmann, S.H. 2001, Identification of acidic, low molecular mass proteins of Mycobacterium tuberculosis strain H37Rv by matrix-assisted laser desorption/ionization and electrospray ionization mass spectrometry. Proteomics 1 494-507. 

Carr medium includes a pH indicator to facilitate identification of acid-producing bacteria. Bromocresol green is an acid indicator that, when incorporated into the media, detects presence of acid (yellow) and neutral-alkaline conditions (blue-green). The modified Carr medium omits the the bromocresol green indicator (incorporating instead CaCOg at 20 g/L) and increases the yeast extract level to 3% (wt/vol). 

Table 187. Identification of acid- and water-aolvbU DNP-amino acida, . by TLC on silica gel G in the system n-propanol-34% ammonium hydroxide (70 + 30). Ascending technique, solvent migration 10 cm, 0.6—Ipig spotted...

A Method for the Identification of Acid Metabolites of Tetrahydrocannabinol (THC) by Mass Fragmentography... 

Identification of Acid Mucopolysaccharides by Gas Chromatographic Analysis of Component Sugars After Chemical Depolymerization Anal. Biochem. 56(2) 465-479 (1973) CA 80 34827s... 

Generally, for the identification of acids and alcohols obtained on hydrolysis the same reactions are used as described on pp. 148 and 247. The simplest case of identification is an ester in which the alcohol can be steam-distilled. After alkaline hydrolysis the alcohol is steam-distilled and identified in the distillate as 3,5-dinitrobenzoate (see p. 150). The acid in the alkaline residue after steam distillation is identified by one of the following procedures (1) the acid is precipitated by acidification (insoluble acids, for example, aromatic), (2) it is precipitated from neutralized solution with S-l-naphthylmethyl-thiuronium chloride (see p. 251), or (3) the acid is distilled off from the acid medium by steam distillation, the distillate is neutralized and evaporated to dryness, and the sodium salt is converted either to the /7-bromophenacyl ester (p. 253) or /7-bromoanilide. 

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