EFFECT OF ACETONITRILE CONCENTRATION ON ACYLCARNITINES MEASUREMENT BY TANDEM MASS SPECTROMETRY

background: the several steps for acylcarnitine analysis by tandem mass spectrometry such as extraction, derivatisation, injection and others, can be influenced by some technical factors improving or impairing the levels of detection. objective: the present study evaluated the effect of different concentrations of the acetonitrile used during blood acylcarnitines measurement on the sensitivity obtained during the analysis. methodology: prior to acylcarnitine analysis by tandem mass spectrometry, samples were re-dissolved in different acetonitrile in water dilutions [50, 60, 70, 80, 90, and 100% (v/v)] and each single blood specimen was processed five times for each dilution. results: it was observed that by increasing the concentration of acetonitrile the intensity of acylcarnitine peaks significantly increased. however at the highest concentrations of acetonitrile, this reacted with the polystyrene material of the microtitre plates, and resulted in peaks appearing in acylcarnitine profiles, specifically at m/z 302. conclusion: a mixture of 70% v/v acetonitrile/water is recommended to use as optimum solvent to dissolve the extracts prior to blood acylcarnitine analysis by tandem mass spectrometry.