High-performance liquid chromatography/thermospray mass spectrometry of some prostaglandins of the F series
作者:J. Abián、E. Gelpí
DOI:10.1002/jms.1190300412
日期:1995.4
Thermospray (TSP) mass spectra and chromatographic characteristics of the prostanoids PGF2α, 6-keto-PGF1α, 2,3-dinor-6-keto-PGF1α, and their methyl esters and methoximes are reported. The spectra of these compounds are dominated by ions of the type [M + H +xNH3 - nH2O]+ in the positive-ion mode and [M - H + xAcOH – nH2O]− in the negative-ion mode (n ranges from 0–4 and x is 0 or 1). The relative abundances of these ions depend on the particular structure, source and interface temperatures and eluent composition. In addition, these compounds show losses of 44 mass units, mainly due to the loss of the C-10–C-11 moiety, as demonstrated by deuterium labelling of PGF2α. Methoximated derivatives of 6-keto-PGF1α also show low-abundance ions due to fragmentation in the position α to the methoxime group. The liquid-phase equilibria of tautomers of 2,3-dinor-6-keto-PGF1α or products thereof which direct its particular chromatographic behavior, can be effectively blocked by methoximation of the keto group thus improving its detectability. Detection limits of 20 ng on-column may be obtained for this derivative. Adsorption and hydrolysis in the interface are the principal factors responsible for this relatively high detection limit.
报告了前列腺素PGF2α、6-酮-PGF1α、2,3-二去氢-6-酮-PGF1α及其甲基酯和甲氧ime的热喷雾(TSP)质谱和色谱特性。这些化合物的质谱在正离子模式下以[ M + H + xNH3 - nH2O]+离子为主,在负离子模式下以[M - H + xAcOH - nH2O]−离子为主(n的范围为0-4,x为0或1)。这些离子的相对丰度取决于特定的结构、来源、界面温度和洗脱液成分。此外,这些化合物表现出44个质量单位的损失,主要是由于C-10-C-11部分的损失,这一点通过对PGF2α的氘标记得到了证实。6-酮-PGF1α的甲氧化衍生物也表现出低丰度的离子,主要是由于在甲氧ime基团的α位发生碎片化。2,3-二去氢-6-酮-PGF1α的互变异构体或其产物的液相平衡会影响其特定的色谱行为,而甲氧化酮基团的处理可以有效阻止这一现象,从而提高其可检测性。对于该衍生物,可以获得20 ng的柱上检测限。界面中的吸附和水解是导致这一相对高检测限的主要因素。