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Investigation of commercial sorbents for the analysis of opioid peptides in human plasma by on‐line SPE‐CE
Author(s) -
Benavente Fernando,
MedinaCasanellas Silvia,
Barbosa José,
SanzNebot Victoria
Publication year - 2010
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200900669
Subject(s) - chromatography , chemistry , solid phase extraction , sample preparation , analyte , detection limit , capillary electrophoresis , extraction (chemistry) , protein precipitation , matrix (chemical analysis)
In this study, we investigated the performance of several commercial sorbents (Sep‐pack ® C18, t C18, C8 and t C2, Oasis ® HLB, Isolute ® ENV+, Strata ™ ‐X and Oasis ® MCX) for the determination of opioid peptides by solid‐phase extraction coupled on‐line to capillary electrophoresis (SPE‐CE). First, standard solutions were analyzed in order to achieve the lowest LOD and the best electrophoretic separations using UV detection. The best results were obtained using C18, C8 and t C2 sorbents, which were examined for the analysis of spiked human plasma samples. A double‐step sample clean‐up pretreatment, which consisted of precipitation with acetonitrile and filtration, was needed to prevent saturation of the on‐line SPE microcartridge. The filtration step was critical to obtain optimum analyte recovery and to clean up the sample matrix. A range of centrifugal filters and filtration conditions were tested and the recoveries of the sample pretreatment were evaluated by CE‐ESI‐MS. The LODs attained through SPE‐CE‐UV were approximately ten‐fold better with C18 than with C8 and t C2. The 0.1 μg/mL LODs achieved by C18‐SPE‐CE‐UV were further improved until we could detect 1 ng/mL concentrations of opioid peptides in plasma samples by C18‐SPE‐CE‐ESI‐MS, due to the outstanding selectivity of the MS detection.