New methods employing capillary liquid chromatography in combination with time-of-flight mass spectrometry (microLC-TOF/MS) were developed for the rapid determination of salcatonin in human urine and plasma. The present approaches utilize (13)C(6)-leucine (19)-labeled salcatonin as internal standard, small matrix volumes and simple sample preparation procedures. They allow TOF/MS to be used as a highly selective detector for providing accurate quantitation of salcatonin. Data acquisition was performed in enhanced mode optimizing the signal for the triply charged species of salcatonin and its internal standard. We demonstrate that the determination of salcatonin is straightforward and reliable and can be performed with excellent linearity (R(2)>0.999), precision and accuracy over the concentration ranges of 2.9-290 pmol/mL in human urine, and 7.3-730 pmol/mL in human plasma.