In this study, SPE-CE-ESI-MS is explored for the preconcentration and separation of dilute solutions of six opioid peptides. First, a CE-ESI-MS methodology was developed and validated. LODs of around 1 microg/mL were obtained for all the studied peptides. For SPE-CE-ESI-MS experiments, a home-made SPE microcartridge containing a C18 sorbent was constructed near the inlet of the separation capillary. After optimizing the on-line preconcentration methodology, LODs between 10 and 0.1 ng/mL were achieved. Repeatability, reproducibility, durability of the microcartridges and linearity of the SPE-CE-ESI-MS methodology were also investigated and compared to the values obtained by CE-ESI-MS. Finally, human plasma samples fortified with opioid peptides were analyzed by SPE-CE-ESI-MS in order to show the potential of the methodology for the analysis of biological fluids.
In this study, the suitability of SPE coupled on-line to CE-electrospray-MS (SPE-CE-ESI-MS) was evaluated for the analysis of neuropeptides in human plasma. First, CE-ESI-MS was investigated and a sample pretreatment based on precipitation with ACN was used for cleanup of plasma samples. The main quality parameters were determined and were consistent with those previously obtained for the analysis of standard mixtures, e.g., the LODs were of around 1 microg/mL. SPE-CE-ESI-MS employing microcartridges containing a C18 stationary phase was explored in order to decrease the LODs. A double-step sample cleanup pretreatment consisting of precipitation with ACN and ultrafiltration through 3000 Da MW cut-off membranes was needed to prevent the microcartridge saturation. Repeatability, reproducibility, linearity, and LODs of the SPE-CE-ESI-MS method and the durability of the microcartridges were studied. The LODs were markedly improved, ranging between 10 and 0.1 ng/mL depending on the peptide.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.