Liquid chromatography with triple-quadrupole and quadrupole-time-of-flight mass spectrometry for the determination of micro-constituents ? a comparison

Abstract

The potential of liquid chromatography with triple-quadrupole mass spectrometry (LC-QqQ MS) was compared to that of quadrupole time-of-flight mass spectrometry (LC-Q-ToF MS) for the determination of microconstituents. Three applications were studied: (1) the ng/l quantification of five human drugs in surface water and waste-water effluents; (2) the quantification and confirmation of three corticosteroids in bovine urine at concentrations of 1-100 microg/l, and; (3) the confirmation of nicotine in rat plasma. In all cases, the criteria of the EU Commission Decision 2002/657/EC were followed (for confirmation analysis two MS/MS ions were monitored, and the ratio of their abundances were calculated and compared with those of standards). With both techniques fully satisfactory results were obtained in almost all instances. That is, unequivocal confirmation according to the most stringent EU criteria, those for "illegal compounds", was possible.One main advantage of LC-Q-ToF MS is that for identification and confirmation purposes, full MS/MS spectra are available after a single injection: no second injection, as required with QqQ MS, is needed. As well as the increased efficiency, the enhanced selectivity due to the impressive mass selectivity of LC-Q-ToF MS must be emphasized, which allows accurate masses of fragment ions to be calculated. Method characteristics such as linear dynamic range and repeatability were found to be essentially the same for both techniques, but LC-QqQ MS has the advantage that its detection limits are somewhat lower.

It is time for a paradigm shift in drug discovery bioanalysis: from SRM to HRMS

“…[11] Thus, currently, in most pharmaceutical companies, one group of scientists (the BA group) performs quantitative analysis using triple quadrupole mass spectrometers while a second group of scientists (the metabolite ID group) performs qualitative analysis using MS and/or HRMS systems. The new HRMS systems that are now available may allow a paradigm shift to a new way of operating in the drug discovery BA arena.…”

Aspectos analíticos e regulatórios na determinação de resíduos de macrolídeos em alimentos de origem animal por cromatografia líquida associada à espectrometria de massas

“…Estes espectrômetros de massas têm sido utilizados em métodos de rotina para triagem de multirresíduos de macrolídeos. 19,[86][87][88][89] Em um estudo para a determinação de seis macrolídeos em ovos, leite integral e mel, usando-se a técnica UHPLC-QToF obtiveram-se limites de detecção entre 0,1 e 1 mg kg -1 , adequados para atender os requisitos regulatórios em análises de rotina, e identificou a desmicosina (tilosina B) em mel, baseando-se na medição de massa precisa e usando o recurso de composição elementar. 19 A tilosina A sofre hidrólise e perde uma molécula de micarose, formando a tilosina B a pH 4, que é muito próximo ao pH médio típico do mel (entre 3,4 -6,1).…”

Quantification of Glucuronide Metabolites in Biological Matrices by LC-MS/MS

“…Therefore, a combination of organic solvents can be used, like for example, ethyl acetate/diethyl ether (1:1, vol/vol), in order to extract both, aglycone and glucuronide. Alternatively, a solid phase extraction can be used (Weinmann, Vogt et al 2000;Stolker, Niesing et al 2004). After the protein removal, a pH readjustment may be necessary in order to gain an acceptable recovery, especially for basic aglycones, which tend to be protonated at acidic pHs of -glucuronidase incubations.…”