title: Development of a mass spectrometry method for the determination of a melanoma biomarker, 5-S-cysteinyldopa, in human plasma using solid phase extraction for sample clean-up.
abstract: 5-S-cysteinyldopa is a well-known pigment intermediate and analysis of its plasma concentration is interesting for the early diagnosis, as well as for evaluation of treatment and follow-up of malignant melanoma. A determination method of 5-SCD in human plasma was developed using solid phase extraction (SPE) on disposable cartridges and liquid chromatography electrospray mass spectrometry (LC-ESI-MS-MS). Compound's sensitivity to light and oxidation requires the addition of anti-oxidative agents (AO), to work in acidic media at 4 degrees C and to avoid light exposure of samples since blood collection. Different solid phases involving covalent binding to phenylboronic groups or dual retention mechanisms were evaluated and extraction cartridges containing both hydrophobic and strong cation exchange functionalities were finally selected. The LC separation of 5-SCD from endogenous catecholamines was achieved by gradient elution on a C18 stationary phase. 5-SCD was detected by multiple reaction monitoring (MRM) performed on ES(+) generated ions. Finally, the method was prevalidated in the lower ng/ml range. Good results with respect to accuracy, trueness and precision were obtained.
authors.affiliation: Laboratory of Analytical Pharmaceutical Chemistry, Bioanalytical Chemistry Research Unit, Institute of Pharmacy, University of Liège, Liège, Belgium.
authors.forename: Gaëlle B
authors.initials: GB
authors.lastname: Martin
authors.forename: Patrice
authors.initials: P
authors.lastname: Chiap
authors.forename: Philippe
authors.initials: P
authors.lastname: Paquet
authors.forename: Gerald
authors.initials: G
authors.lastname: Pierard
authors.forename: Pascal
authors.initials: P
authors.lastname: de Tullio
authors.forename: Yves
authors.initials: Y
authors.lastname: Martin
authors.forename: Eric
authors.initials: E
authors.lastname: Rozet
authors.forename: Philippe
authors.initials: P
authors.lastname: Hubert
authors.forename: Jacques
authors.initials: J
authors.lastname: Crommen
authors.forename: Marianne
authors.initials: M
authors.lastname: Fillet
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003548:Cysteinyldopa / Q000097:blood*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008545:Melanoma / Q000097:blood*; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods
chemical_list: D014408:Biomarkers, Tumor; D003548:Cysteinyldopa