Nitrogen metabolite identification

Other monovalent elements (F, Cl, Br, and I) are counted as hydrogens, trivalent elements (P) are counted as nitrogen, and tetravalent elements (Si) are included with carbon. For chemically possible formulae, r+ db> — 1.5. Odd-electron ions (M+ ) will have an integer value and even-electron ions will have 0.5 r + db more than expected, so round up to next lowest integer.32,33 By way of example, Kind and Fiehn139 have described an integrated application of accurate mass data to metabolite identification, constrained by isotope abundance information and valence rules, in addition to the KI (Section 9.10.4.3.2). 

The prediction of retention times in a given eluent from log P has been proposed for aromatic hydrocarbons.19 The log A values of phenols21 and nitrogen-containing compounds22 were also related to their logP, and the calculated log P was used for the qualitative analysis of urinary aromatic acids, i.e. for the identification of metabolites in urine from the differences of log P in reversed-phase liquid chromatography.23,24... 

E. W. Taylor, W. Jia, M. Bush, and G. D. Dollinger, Accelerating the drug optimization process Identification, structure elucidation, and quantification of in vivo metabolites using stable isotopes with LC/MS" and the chemiluminescent nitrogen detector, Anal Chem. 74 (2002), 3232-3238. 

Taylor, E.W. Jia, W. Bush, M. Dollinger, G.D. Accelerating the Drug Optimization Process Identification, Structure Elucidation, and Quantification of In Vivo Metabolites using stable isotopes with LC/MSn and the chemiluminescent nitrogen detector, AnaZ. Chem. 74(13), 3232-3238 (2002). 

Under nitrogen-limiting conditions, two Rhodococcus erythropolis strains, able of mineralizing 2,4-DNP as the sole source of carbon, have been isolated. Both strains metabolized 2,4-DNP, present at a final concentration lower than 0.5 mM with liberation of stoichiometric amotmts of nitrite and of low amoimt of 4,4-dinitrohexanoate [71]. The identification of the last compound as the only organic metabolite of... 

Despite the increasing availability of modern classification techniques based on similarities at the gene level, routine laboratory identification of yeasts still relies on microscopic comparison of the isolate s cell shape, how it reproduces (asexually versus sexual), as well as utilization of various carbon and nitrogen compounds, and metabolites produced. 

Fig. 7.2 Chromatogram of acidic metabolites extracted from the urine of a normal child using DEAE-Sephadex and re-extraction with solvents after ethoxime formation and freeze-drying by reconstitution in water, acidification with hydrochloric acid, saturation with sodium chloride, and solvent extraction with diethyl ether (three times) and ethyl acetate (three times), evaporation of the solvents from the combined extracts using dry nitrogen and trimethylsilylation using the minimum quantity of BSTFA. Separated on 10 per cent OV-101 on HP Chromosorb W (80-100 mesh) by temperature programming from 110°C to 285°C at 4°C min with an initial 5 min isothermal delay. Peak identifications are 1, phenol plus lactate 2, glycollate 3, cresol 4, 3-hydroxyisovalerate 5, benzoate 6, phosphate 7, succinate 8, 3-methyladipate 9, 3-hydroxy-3-methyl-glutarate 10, 4-hydroxyphenylacetate 11, homovanillate plus some aconitate 12, hippurate 13, citrate 14, vanilmandelate 15, n-tetracosane (standard) 16, n-hexacosane (standard).

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