Improved analysis of derivatized steroid hormone isomers using ion mobility-mass spectrometry (IM-MS).

Over the last decade, applications of ion mobility-mass spectrometry (IM-MS) have exploded due primarily to the widespread commercialization of robust instrumentation from several vendors. Unfortunately, the modest resolving power of many of these platforms (~40-60) has precluded routine separation of constitutional and stereochemical isomers. While instrumentation advances have pushed resolving power to >150 in some cases, chemical approaches offer an alternative for increasing resolution with existing IM-MS instrumentation.

Improved Ion Mobility Separation and Structural Characterization of Steroids using Derivatization Methods.

Steroids are an important class of biomolecules studied for their role in metabolism, development, nutrition, and disease. Although highly sensitive GC- and LC-MS/MS-based methods have been developed for targeted quantitation of known steroid metabolites, emerging techniques including ion mobility (IM) have shown promise in improved analysis and capacity to better identify unknowns in complex biological samples. Herein, we couple LC-IM-MS/MS with structurally selective reactions targeting hydroxyl and carbonyl functional groups to improve IM resolution and structural elucidation.

Targeted glucocorticoid analysis using ion mobility-mass spectrometry (IM-MS).

Introduction: Ion mobility-mass spectrometry (IM-MS) is an emerging technique in the -omics fields that has broad potential applicability to the clinical lab. As a rapid, gas-phase structure-based separation technique, IM-MS offers promise in isomer separations and can be easily combined with existing LC-MS methods (i.e.

Toward Routine Analysis of Anabolic Androgenic Steroids in Urine Using Ion Mobility-Mass Spectrometry.

Anabolic androgenic steroids (AAS) make up one of the most prevalent classes of performance-enhancing drugs banned by the World Anti-Doping Agency (WADA) due to the competitive advantage they can afford athletes. Mass spectrometry-based methods coupled with chromatographic separations have become the gold standard for AAS analysis because of the superior sensitivity and selectivity provided. However, emerging analytical techniques including ion mobility spectrometry (IMS) have been demonstrated in recent applications as a means to further characterize and identify potential unknowns while simultaneously delivering improved sensitivity by filtering noise.

Improved Identification of Isomeric Steroids Using the Paternò-Büchi Reaction with Ion Mobility-Mass Spectrometry.

The Paternò-Büchi (PB) reaction is a common organic reaction in which a carbonyl radical formed by exposure to UV radiation reacts with an alkene to form an oxetane ring. Recent analytical applications of this reaction have included the determination of C═C bond position in lipid fatty acyl tails using tandem mass spectrometry. Our group has recently investigated methods for structurally modifying steroid isomers to improve their identification and resolution using ion mobility spectrometry.

Synthesis of trifunctional thiazolyl amino acids and their use for the solid-phase synthesis of small molecule compounds and cyclic peptidomimetics.

Chiral thiazolyl amino acid building blocks for the solid-phase synthesis of small molecules, peptides, and cyclic peptides have been designed and synthesized starting from Fmoc protected asparagine and glutamine. In efforts to demonstrate the usefulness and validity of such building blocks, a small library of 16 new thiazole containing small molecules has been prepared and characterized. Additionally, we report the use of the newly prepared trifunctional thiazolyl glutamine for the on-resin, head-to-tail synthesis of cyclic peptides.