Automated mass spectrometric analysis of urinary free catecholamines using on-line solid phase extraction

Analysis of catecholamines (epinephrine, norepinephrine and dopamine) in plasma and urine is used for diagnosis and treatment of catecholamine-producing tumors Current analytical techniques for catecholamine quantification are laborious, time-consuming and technically demanding Our aim was to develop an automated on-line solid phase extraction method coupled to high performance liquid chromatography-tandem mass spectrometry (XLC-MS/MS) for the quantification of free catecholamines in urine Five microlitie urine equivalent was pre-purified by automated on-line solid phase extraction, using phenylbotonic acid complexation. Reversed phase (pentafluorophenylpropyl column) chromatography was applied Mass spectrometric detection was operated in multiple reaction monitoring mode using a quadrupole tandem mass spectrometer with positive electrospray ionization Urinary reference intervals wet e set in 24-h urine collections of 120 healthy subjects XLC-MS/MS was compared with liquid chromatography with electrochemical detection (HPLC-ECD). Total run-time was 14 min. Intra- and inter-assay analytical variations were 0.99) Quantification limits were 1 47 nmol/L, 15 8 nmol/L and 11 7 nmol/L for epinephrine. norepinephrine and dopamine, respectively XLC-MS/MS correlated well with HPLC-ECD (correlation coefficient >0 98) Reference intervals were 1-10 mu mol/mol, 10-50 mu mol/mol and 60-225 mu mol/mol creatinine for epinephrine, norepinephrine and dopamine, respectively Advantages of the XLC-MS/MS catecholamme method include its high analytical performance by selective PBA affinity and high specificity and sensitivity by unique MS/MS fragmentation (C) 2010 Elsevier B V. All rights reserved