| Mass spectral characterization of molecules larger than 2 kDa has recently become commonplace with the advent of low energy ionization techniques such as electrospray ionization. The complexity of these large molecule spectra requires the high resolving power, sensitivity, and mass accuracy of the Fourier transform mass spectrometer for characterization of even medium size polymers, proteins, oligosaccharides, and oligonucleotides.; The Fourier transform mass spectrometer is capable of unprecedented resolving power for separations allowing isolation of single isotopic peaks of 29 kDa proteins. With tandem mass spectrometry, this provides a unique method for determining the number of {dollar}sp{lcub}13{rcub}{dollar}C atoms in a large protein ion. Tandem mass spectrometry at lower isolation power also provides the ability to isolate a specific ion of interest and dissociate it preferentially, allowing determination of the lineage of fragment ions from these complex macromolecular spectra which significantly enhances the quality of the mass information available. This approach allows determination of a significant amount of sequence specific data on protein samples in excess of 40 kDa, characterization of the branching structure of oligosaccharides isolated from glycoproteins, and sequencing of oligonucleotides up to 50 base pairs in length. New fragmentation techniques such as infrared and ultraviolet photodissociation provide extensive fragmentation in biomolecule spectra. UV photodissociation in particular yields high energy ions which provide complementary data to the infrared and standard collisional activation methods allowing rapid determination of the terminus associated with a given fragment ion. And, finally, electrospray Fourier-transform mass spectrometry is amenable to study of polymeric samples where determination of the molecular weight distribution is critical.; Much of the data generated by the fourier transform mass spectrometer is very complex and requires extensive efforts in data interpretation, which facilitates the desire for computerized data interpretation routines. These routines include automated deconvolution routines which pulls the uncharged mass data out of the multiply charged m/z data generated by electrospray, and computerized database searching algorithms which use mass spectral fragmentation data to search protein and DNA databases for rapid and specific identification of unknown proteins. |
