High-performance liquid chromatography of ergot alkaloids

Determination of dihydroergocryptine in human plasma and urine samples using on-line sample extraction?column-switching reversed-phase liquid chromatography?mass spectrometry

“…Despite being extremely sensitive, in particular when coupled to mass selective detection (MSD), gas chromatography [26] does not prove to be the method of choice due to both the analyte's low volatility and thermal sensitivity. Therefore, prior derivatization, e.g., by means of bis(trimethylsilyl) acetamide (BSA) in the reaction port of the gas chromatograph or N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) is required, as described for determination of lysergic acid diethylamide (LSD) [27].…”

“…Therefore, prior derivatization, e.g., by means of bis(trimethylsilyl) acetamide (BSA) in the reaction port of the gas chromatograph or N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) is required, as described for determination of lysergic acid diethylamide (LSD) [27]. In addition, also planar chromatographic techniques [26] do not meet the basic requirements of both separation efficiency and accuracy.…”

“…The fact that ergot alkaloids possess different amine functions requires the use of buffered mobile phase systems and performed by either isocratic elution [6,8,14,[24][25][26][28][29][30] or in the gradient mode [1,[7][8][9]13,15,16,25] on C 18 and C 8 columns. In some applications acetonitrile-10 mM ammonium carbonate mixtures [1,9,13,24,25,28] were used but except Ref.…”

“…[8]. In investigations employing both bare silica gel and reversed-phase materials, such as, e.g., C 18 , C 8 and C 2 supports, chloroform-methanol, chloroform-ethanol and chloroform-n-hexane-methanol mobile phases were used on bare silica gel, whereas acetonitrile-ammonium carbonate eluents are preferably applied on reversed-phase sorbents [26]. An extensive study addressing the influence of pH within the range of 2-13 on separation selectivity of dihydroergotoxine metabolites is given in Ref.…”

“…However, liquid chromatographic procedures, coupled to mass spectroscopic detection (MSD), provide some crucial advantages, in particular with concern to specificity. Indeed, high performance liquid chromatographic methods [1,[6][7][8][9]13,[15][16][17][24][25][26][27][28][29][30] prevail in analytical investigations of ergot alkaloids targeted either to get more precise insight into the metabolic pattern or to obtain thorough information of their concentrations in a biological environment, such as, e.g., serum or plasma, urine, tissue, etc. Among them three methods apply the selective "on-line" LC-MS hyphenation [13,15,17] allowing direct and unequivocal structural assignment of the compounds of interest even in those cases where co-elution of two or more species occurs provided ionization energy is not quantitatively consumed by the interfering ones.…”