Determination of amino acids and amines in mammalian decomposition fluid by direct injection liquid chromatography-electrospray ionisation-tandem mass spectrometry

Abstract

PAPER Lewis et al. Determination of amino acids and amines in mammalian decomposition fl uid by direct injection liquid chromatography-electrospray ionisation-tandem mass spectrometry Determination of amino acids and amines in mammalian decomposition fluid by direct injection liquid chromatography-electrospray ionisation-tandem mass spectrometry †

Analysis of free amino acids in natural waters by liquid chromatography–tandem mass spectrometry

“…Calibration curves showed good linearity (R 2 >0.990) up to maximum concentrations that ranged between 5 to 20 ng µL -1 for all analytes. Instrumental detection limits, estimated at signal-to-noise (S/N) ratios of 3, ranged from 1 to 190 pg on column (0.2 -38 pg µL -1 ), which is consistent with our previous study [25]. The variabilities of retention time and MRM ratio were calculated from repeat injections (n=10) of a solution containing 1 ng µL -1 of each amino acid.…”

“…We have previously developed a method for the analysis of amino acids and amines in mammalian decomposition fluids by LC-MS/MS [25]. In this method, direct injection of samples was used.…”

“…Unless otherwise stated, all liquid chromatography and tandem mass spectrometry conditions adopted in this work were the same as we have previously reported in Swann et al [25].…”

“…Infusion experiments were conducted to determine the MRM transitions of the amino acids not analysed previously [25], i.e., alanine, aspartic acid, cysteine, glycine, glutamine and the deuterated surrogates, alanine-d3, leucine-d3, glutamic-d3 acid, glycine-d2 and phenyl-d5alanine-d3, so that they could be incorporated into the present analytical method. The parent ion to product ion transition data for the remaining amino acids were as obtained previously [25]. A significant improvement on the previous method was the introduction of deuterated standards as surrogate standards to account for matrix effects and recovery, and also for quantification.…”

“…The same research group later also introduced a method using tandem mass spectrometry for the analysis of free amino acids in ultrapure water [ 2 1 ] . S i n c e t h e n , amino acids have been analysed by LC-MS in a range of applications involving a variety of matrices, including foods [22,23] and biological samples [24,25]. However, there are no reports to date on the application of LC-MS for the analysis of amino acids in natural waters, particularly waters containing natural organic matter.…”