用于体液的生物质谱直接分析的多维在线SPE技术

仪器资料 · 发表于 2018-7-7 07:56:19

用于体液的生物质谱直接分析的多维在线SPE技术
Multidimensional On-Line SPE for
Undisturbed LC-MS-MS Analysis of Basic
Drugs in Biofluids

Abstract
In bioanalytical LC-MS-MS matrix effects influencing the ionization process are a major concern
with respect to the quality of the results obtained. In general such matrix effects are directly
related to an insufficient sample clean-up of the biofluids. In order to establish a MS-adequate
clean-up procedure for basic analytes present in biofluids (e.g. urine, plasma) which is based
on solid-phase extraction (SPE) principles a combination of tailor-made SPE column packings
and automated column-switching was developed. This novel, multidimensional (MD) SPE
platform relies on the combination of a SPE column packed with a restricted access material
(RAM) allowing size-exclusion and reversed phase chromatography (SEC-RPC) and a second
SPE column packed with a mixed-mode phase (MMP) allowing ion exchange and reversed
phase chromatography (IEX-RPC). For the evaluation of this MD-SPE platform 8 tricyclic
antidepressants and two metabolites were chosen as model analytes. In order to monitor matrix
effects, i.e. ion suppression, postcolumn infusion experiments were performed and compared
with a two-dimensional SPE column mode (SEC-RPC). The MD-SPE platform is highly efficient
for removal of low and high molecular weight sample components which suppress ionization to
varying extend. In addition electrospray ionization of the model analytes is not affected by
inter- or intra-individual variations in the composition of the matrix investigated. It is also
independent of the species the biofluids originate from. It was demonstrated that the MD-SPE
platform has a generic potential with respect to on-line SPE of basic drugs having a pKa > 6.5
and a moderate to low polarity and being present in different biofluids.