CHARACTERIZATION OF OVER-THE-COUNTER COUGH COLD MEDICATIONS BY LIQUID-CHROMATOGRAPHY ELECTROSPRAY MASS-SPECTROMETRY

Electrospray ioniztion (ESI) high-performance liquid chromatography/mass spectrometry (LC/MS) has been utilized for the characterization of the active ingredients in over-the-counter (OTC) cough and cold medications. The use of in-source collision-induced dissociation (CID) on a single quadrupole instrument produced spectra with characteristic fragment ions. The in-source CID potential was rotated through different energies on alternate scans throughout the chromatographic run. The spectra across a given chromatographic peak were summed and averaged to give composite spectra which displayed molecular ions in addition to fragment ions, producing library searchable spectra of analytes with varying collisional stabilities, within a single chromatographic run. These spectra were then saved into a library which was created with the following OTC drugs, phenylpropanolamine, doxylamine, pyrilamine, chlorpheniramine, brompheniramine, dextromethorphan, cyclizine, and clemastine. The active ingredients in commercial OTC remedies were detected and characterized using this created library. The method requires no derivatization and minimal sample preparation, is applicable to a range of analytes, and can be fully automated for multiple sample analyses.