Abstract
The method of matrix-assisted laser desorption/ionization mass spectrometry has been used to solve some bioanalytical problems, which are difficult to analyze by general methods. For the selection of a proper laser wavelength and matrices, seven matrices were used with laser wavelength of 266 and 355nm. The results show that with a wavelength of 355nm better results could be obtained with most of the matrices. The molecular weight of cytochrome c, which was separated by gel electrophoresis and electro-blotted onto nitrocellulose membrane, was determined by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The accuracy was better than 0.1%, which is much higher than that of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The three components of protein mixture extracted from crude peanut oil was directly determined by MALDI-MS. The result also demonstrated that these proteins are in a free manner. Since these proteins are in a 2S bond, with the traditional method, SDS-PAGE, it is not possible to decide whether the proteins exist in a combination mode or in a free manner. Water-soluble polymers stained with dyes are used in the technique of two-phase aqueous solution, which is used for separating biomaterials. By using MALDI, the number of the dye molecules that react with the polymer molecules can be determined, which is difficult to determine by other methods.
