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Column packings widely used for high-performance liquid chromatography (HPLC) mostly are based on porous silica microspheres with certain pore sizes and pore size distributions. Such materials have the most desirable compromise of properties that provide for effective and reproducible separations over a wide range of operating conditions. To provide desired separation characteristics, several manufacturers specially synthesize the silica particles for these packings. While such column packing materials have general utility for a wide range of needs, special silica-based particles have been synthesized with different physical conformations for special separation goals. This presentation describes some atypical types of silica-based particles with unique separation properties that enlarge the capabilities of HPLC methods.

The advantages to the use of both mass spectrometry (MS) and Fourier transform infrared spectrometry (FT-IR) in combination for the structural characterization of the tryptic digest of a model globular protein is demonstrated. HPLC has been interfaced to both spectroscopic techniques and has provided a high degree of structural detail for the target protein. beta-Lactoglobulins A and B were digested with trypsin and chromatographed with narrow-bore, reversed-phase HPLC. As determined by LC-FT-IR spectrometry, the conformation of each form of intact beta-lactoglobulin was randomized upon elution. The particle beam and the electrospray LC-MS interfaces enabled the acquisition of spectra for nanogram injection quantities. The primary structures were determined from the accurate molecular mass determinations of the digest fragments. Infrared spectra confirmed the presence of some amino acid functionalities.