[Determination of oligopeptide by IR matrix-assisted laser desorption ionization mass spectrometry]

Luteinizing releasing hormone analog (LRH-A), renin substrate tetradecapeptide and angiotensin I were analyzed with infrared-matrix assisted laser desorption ionization/Fourier transform ion cyclotron resonance mass spectrometry (IR-MALDI/FTICR MS). 2,5-Dihydroxybenzoic (DHB) and succinic acid (SA) were used as matrices. The m/z of oligopeptides were determined with an error less than 4 x 10(-6). A series of characteristic fragment ions of peptides were obtained by increasing the laser power density appropriately. Their elemental compositions and the first order structures were confirmed. A sensitive, rapid and accurate method was established for the determination of oligopeptide.