Micro extraction to quantitate spermidine and spermine in human urine and blood by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

Spermidine and its derivative, spermine, are basic compounds with unique roles in physiological function. This study used matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) to monitor these analytes in human urine and blood. The MALDI-TOF MS is also suitable when a high-throughput analytical method is required. Unlike liquid chromatography (LC)–MS, MALDI-TOF MS does not require a mobile phase in sample separation and generates very little organic waste. Micro liquid–liquid extraction was also performed to minimize the use of organic solvents in this study. After alkalization step, biosamples were prepared by adding a small volume (20 μL) of organic solvent to concentrate, and purify the spermidine and spermine contained in the urine and blood samples. A suitable extraction protocol was developed after optimizing various conditions associated with extraction efficiency. The proposed method was then successfully used to monitor these compounds in human urine (mean value < 1 μg/mL) and blood (mean value > 1 μg/mL).