Isopropanol Protein Precipitation for the Analysis of Plasma Free Metanephrines by Liquid Chromatography–Tandem Mass Spectrometry

Abstract

Isopropanol protein precipitation is a novel and effective off-line sample preparation method for metanephrines that offers a less expensive alternative to on-line solid-phase extraction for low-volume testing and requires a sample volume of only 200 microL. The mass spectrometric analysis time is equivalent to that of solid-phase techniques.