Plasma Catecholamines: Laboratory Aspects

Abstract

In this review the methods used for analysis of plasma catecholamines in clinical chemical laboratories are discussed. The physiology of catecholamines as well as their measuring indications are discussed, together with concise evaluation of the methods most commonly used, namely indirect radioenzymatic assays or direct determinations by high-performance liquid chromatography combined with either electrochemical or fluorometric detection. The main advantage of radioenzymatic assay is its sensitivity and thus the need for only a small sample. Liquid chromatographic methods in general are less tedious, relatively rapid, and cheap, and omit the use of radionuclides. Both of these methods, however, are subject to a number of analytical errors, which can only be avoided by proper development of methods and skilled use of these methods. Little routine work is done using either radioimmunoassay or gas-chromatography.

Analysis of 9-fluorenylmethyloxycarbonyl derivatives of catecholamines by high performance liquid chromatography, liquid chromatography/mass spectrometry and tandem mass spectrometry

“…HPLC, LC/APCI-MS and ES/CID tandem mass spectrometry of the FMOC derivatives of DA, NE, EPI and DHBA have not been previously documented. Oxidation 30,31 of the catechol ring to form a quinone catecholamine structure at pH 8-9 does not occur in the FMOC derivatization procedure used in this study. This may be due to the presence of acetonitrile in the reaction mixture.…”

Hormonal responses and cardiac filling pressures in head-up or head-down position and pneumoperitoneum in patients undergoing operative laparoscopy

“…Adrenaline and noradrenaline concentrations in plasma were analysed by high performance liquid chromatography with coulometric detection, as described in detail elsewhere. 17 The detection limits of adrenaline and noradrenaline were 0.1 nmol litre 91 and 0.075 nmol litre 91 , respectively. Intraand inter-assay coefficients of variations (cv) for adrenaline were 11% and 11% at 0.26 nmol litre 91 and for noradrenaline, 7.8% and 15.2% at 1.42 nmol litre 91 , respectively.…”

Measurement of catecholamines and their metabolites

“…However, the methods are somewhat complex and tedious, requiring minute attention to detail, and are not suited to routine clinical chemistry departments. Even though catecholamines possess natural £uorescence, many other compounds and drugs present in plasma have absorption and emission maxima at the same wavelengths 113 and consequently £uorimetric methods require highly speci¢c isolation techniques. While conversion of the catecholamines to £uorescent derivatives with trihydroxyindole or ethylenediamine can enhance sensitivity, speci¢city is still limited due to drugs and dietary interferences.…”

“…The stability of catecholamines and their metabolites in plasma has attracted signi¢cantly more attention than the study of their stability in urine collections. Excellent reviews of the problems associated with sample handling and preparation for liquid chromatographic assays for plasma catecholamines have been reported by Goldstein, 165 Nyyssonen and Parvianen, 113 Hjemdahl 121 and Bouloux et al 59 There are a number of variables that must be considered when collecting blood samples for plasma catecholamine determination. These include: the time of day, as noradrenaline exhibits a diurnal pattern; sampling site, as arterial catecholamine concentrations are lower than venous concentrations; environmental stress; in£uence of posture, as plasma catecholamines concentrations can increase 2-3-fold from a supine to an upright position; and the in£uence of smoking and ca¡eine intake on subsequent levels.…”