Measurement of urinary metadrenaline and normetadrenaline by liquid chromatography tandem mass spectrometry for the diagnosis of phaeochromocytoma

摘要

Background: Measurement of metadrenalines has been recommended in the investigation of phaeochromocytoma. Urinarynassays remain the most common; however, drug interference is still one of the main challenges for analytical systems. Wenhave developed a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the quantification of totalnurinary normetadrenaline and total urinary metadrenaline, which does not require extraction procedures prior to analysis.nMethod: Total urinary normetadrenaline and total urinary metadrenaline were individually quantified by electrospray ionizationnin the multiple-reaction monitoring mode. Deuterated internal standards were used and an acid hydrolysis step was used tonconvert conjugated metabolites into free metadrenalines. Chromatographic separation was achieved using a PhenomenexnLuna 3m PFP column followed by analysis on an API 3200 LC–MS/MS.nResults: Linearity was exhibited across the calibration range for both normetadrenaline (r ¼ 1, P, 0.0001) and metadrenalinen(r ¼ 1, P, 0.0001) with the limit of quantification of 0.05 and 0.02 mmol/L, respectively. Intra-assay imprecision for bothnnormetadrenaline and metadrenaline was less than 5.5% with % coefficient of variations of less than 4%. Inter-assaynimprecision was less than 13%. Neither noradrenaline or adrenaline interfere with the assay as determined by the spiking ofnsamples with high concentrations of noradrenaline or adrenaline (P . 0.05). Acceptable analytical performance was seen withncomparison to a high-performance liquid chromatography method and on External Quality Assessment returns.nConclusions: An analytically simple and sensitive method has been developed and evaluated for the analysis of total urinarynnormetadrenaline and total urinary metadrenaline which is now in routine use.