Adding Mass Selective Detection to Improve Analytical Sensitivity and Maximize Confidence in Results for Impurity Profiling by UHPLC

Analytical methods to check the purity of active pharmaceuticals have been described in pharmacopeias. HPLC-UV detection is the most common analytical liquid chromatography technique for impurity profiling in QC laboratories because of its ease-of-use, robustness, and reliability. However, there are many occasions where ultraviolet (UV) detection has limitations, including cases where analytes or impurities have poor UV absorption, peaks coelute, and unknowns need analyzing, especially when it is necessary to investigate out-of-specification (OOS) results. In addition, degradation products may be significantly less UV active than the Active Pharmaceutical Ingredient (API) due to the loss of the chromophore. In these situations, using a mass detector in series with the UV detector adds significant confidence to the analytical results. This Application Note demonstrates the benefits of mass detection for unambiguous peak identification, determining compound coelution, detection of compounds with weak UV absorbance, and compound library searching for added confirmation with the InfinityLab LC/MSD XT system.