Monohydroxy compounds, identification

G) Identification of Monohydroxy Compounds. The evolution of hydrogen chloride, when acetyl chloride or phosphorus trichloride is added to a compound, indicates the possible presence of a hydroxy group. For identification purposes a derivative should be prepared. 3, 5-Dinitrobenzoic acid forms crystalline derivatives with hydroxy compounds. The melting points of the esters are utilized for identification. 

Another barnacle species, Elminius modestus, was found to produce mono and trihydroxy fatty acids [146]. Analysis of the extract of whole animal homogenates by TLC provided two hatching factor active bands. The more polar band was tentatively identified as a trihydroxy fatty acid (THFA) band. The less polar band had an / r value similar to a 5-HETE standard. The compounds from this latter band were eluted from the TLC plate, methylated, and trimethylsilylated. GC-MS analysis detected several HEPE s and small amounts of monohydroxy derivatives of Ci8 1, C18 2, and C22 fatty acids. Hydrogenation and subsequent GC-MS analysis allowed identification of the major compound as 8-HEPE (ca. 70%). Five to ten percent of 9-, 11-, and 15-HEPE and minor amounts of 5-, 6-, 12-, and 13-HEPE were also detected. No stereochemical features of these oxylipins were determined. 

All lutl alleles are recessive mutations (Fig. 3 A) that accumulate an additional carotenoid with an HPLC retention time and UV/visible absorption spectrum characteristic of a monohydroxy / , e-carotenoid (an a-carotene derived xanthophyll). The identification of the accumulating compound as zeinoxanthin ()3,e-caroten-3-ol) was confirmed by mass spectrometry (Pogson et al., 1996). The only difference between lutein and zeinoxanthin is the presence of an hydroxyl group on carbon 3 of the -ring in lutein. The decrease in lutein and its partial replacement by its immediate precursor, zeinoxanthin, defines lutl as a mutation... 

It is emphasized that, owing to the inherent selectivity of (LE)SS, sample cleanup procedures can often be minimized. An important example is the analysis in a crude river sediment extract of ul-tralow traces of dibenzo[d ,/]pyrene, the most carcinogenic PAH known to man. Another interesting application is the identification and quantification of PAH metabolites in samples for biological monitoring. Although SS is not appropriate for highly polar compounds it can be applied to monohydroxy PAHs. 

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See also in sourсe #XX -- [ ]

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