EDITORIAL
The Handsome 600-Pound Gorilla Who is the handsome 600-pound gorilla beating up on analytical problems these days? I suspect I'd get several volunteers for such a statement, but I'm picking mass spectrometry as this month's gorilla for another edition of my discussions of analytical chemistry frontiers. Molecular MS has for decades been an important analytical tool for molecular formula, mass, and structure identification. Researchers have successfully deciphered the fragmentation chemistry of the electron impact ionization source, and GC has been wed with digital data storage systems and moderate-cost time-of-flight and quadrupole mass analyzers. Ultrahigh resolution and tandem instruments also played a substantial role in mass spectral research and applications. There is a certain parallel between the introduction of 13C and multidimensional techniques into proton NMR spectroscopy and recent developments in MS. Important discoveries have taken place, and the pace of change has quickened. Although classical mass spectral approaches remain a solid foundation of analytical applications, there is a vastly broadened horizon of challenges and opportunities. Mass spectrometric experiments are under development to probe the three-dimensional structures or folding of biopolymers. The drivers of change are several. Matrix-assisted laser desorption, fast atom bombardment, and electrospray ion sources have opened more routine ways to volatilization and ionization, including multiple ionization, of large mass structures. Tandem or multiple mass analysis can be done with high resolution and mass accuracy on foursector combinations or at moderate cost with quadrupole devices. Probably most important are the sophisticated new techniques of inducing gas-phase dissociation chemistry with controllable energy deposition and reactive target
gases as well as the opportunity to use time as a variable in ion-molecule reactions with cyclotron resonance and quadrupole ion storage devices. The elucidation of large mass structures requires more delicate and chemically versatile ways to pry such structures apart. The applications t h a t can be envisioned through these new advances are most obvious and exciting in the biomolecular area. Coupled with new separations capabilities and principles emerging in capillary electrophoresis, CZEIMS may assume a future importance rivaling that of GCIMS. Drinking the full content of this new cup will require research aimed a t understanding t h e newly accessible dissociation chemistry of very diverse large mass structures of biological origin. This will be a substantial task, and choices of its focus will be important to the field; the dividends may include greatly enhanced roles for the analytical community in analysis and research in molecular biology. The opportunities and challenges are not confined to biological applications. Surface-induced dissociation is emerging as another route to controllable energy deposition in ions; it may also yield new wrinkles in functional group analysis of molecular surfaces. I look forward to incorporation of the recent innovations into simplified low-cost instruments useful for routine monitoring1 sensing applications in the human and natural environment. It is good to see MS assuming a more central role as a vigorous player in measurement science frontiers. I t should commensurately assume a larger place in our undergraduate- and graduatelevel curicula as well as in continuing education. The opportunities for young scholars in this field seem quite bright.
ANALYTICAL CHEMISTRY, VOL. 65, NO. 7, APRIL 1, 1993
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