Quantitative electrospray LC-MS and LC-MS/MS in biomedicine

The use of electrospray LC-MS and LC-MS/MS for the quantitative determinati on of two low molecular weight (<500 Da) organic compounds in human plasma (Lovastatin) and cell supernatants (Arachidonic acid) and medium molecular weight (>2000 Da) endogenous peptides (Endothelins) in supernatants of huma n umbilical vein endothelial cell cultures is reported. These methods make use either of deuterium labelled or structurally similar molecules as inter nal standards for quantitation and one or more pre-purification steps previ ous the LC-MS analysis. Linear calibration curves and detection limits arou nd 50 pg ml(-1) were obtained in all three cases. (C) 1998 Elsevier Science B.V. All rights reserved.