Phenanthrimidazoles as fluorescent derivatives in the analysis of fatty acids by high-performance liquid chromatography
Phenanthrimidazoles as fluorescent derivatives in the analysis of fatty acids by high-performance liquid chromatography
复制标题
菲咪唑作为荧光衍生物用于高效液相色谱法分析脂肪酸
DOI：
10.1016/s0021-9673(00)80316-7
复制
发表时间：
1980
影响因子：
4.1
通讯作者：
J. Lloyd
中科院分区：
文献类型：
--
作者：
J. Lloyd
In methyl polyphosphate, prepared in chloroform, fatty acids condense with 9,10-diaminophenanthrene to form 2-substituted phenanthrimidazoles. The reaction proceeds to completion within 3–6 min at 85° to give, in general, yields reproducibly in excess of 95%. Exceptions are linolenic acid, from which the yield is reproducibly 91%, and formic acid, from which no derivative is obtained under these conditions.When the 2-substituent is unconjugated with the nucleus the mean quantum yield of fluorescence from derivatives of seventeen different acids under conditions relevant to the derivatives' chromatography (methanolic solvents) is 0.68 in nitrogen-purged solvents and 0.31 in aerated solvents, both with standard deviations of 0.02. The fluorescence emission exhibits overlapping maxima at 367 and 382 nm, with a width at half maximum peak height of 3120 cm-1. Under nitrogen, but not in the presence of air, quantum yields vary negligibly with the water content of the solvent over the chromatographically useful range. At higher concentrations of water the formation of weakly fluorescent micelles may occur. Above the acetic derivative the molar absorptivities in methanolic solvents are independent of the substituent in the sixteen unconjugated derivatives examined. At 254–255 nm the man value is 90133. Other weaker absorbance maxima are available at various points up to 354 nm. From these results the intrinsic fluorescence sensitivity value of the derivatives is greater than that of the 4-hydroxymethyl-7-methoxycoumarin ester derivatives by a factor of 12.The reaction mixture may be injected directly on to reversed-phase (octadecylsilyl) columns. Of the nineteen acids examined, up to erucic in molecular weight, the derivatives of all except the pairn-butyric and crotonic are separated from one another in aqueous methanol containing 0.01Mammonium carbonate. On gradient elution, equimolar amounts of different acids give essentially constant peak areas, in contrast to the methoxycoumarins.
