Europium complexes with six types of tris fi-diketones in the absence and presence of 1,10-phenanthroline were accurately analyzed qualitatively and quantitatively using both infusion electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectrometry (FL), which is usually used as the analytical method. Detection limits for compounds extracted with acetonitrile were 1-100ppb corresponding to those by FL.