Mallikharjuna Reddy, Associate Director – Quality, Clearsynth drew from his experience of 20+ years in analytical research and development and expertise in impurity profiling and quantification of GTI by LCMSMS/GCMS, Reference Standards during his session on ‘Dealing with challenges in testing and use of Stable Isotopic Labelled Standards’ at ADL Conclave 2022.
He began his session by sharing information on Stable Isotopic Labelled Standards and their application in analytical development. He went on to explain that labelled standards are preferred as internal standards (ISTD) for varied reasons. To begin with, they improve the efficiency of bioassay or quantification methods.
They minimise changes in preparation/extraction/ionization and offer phytochemical properties almost similar to the unlabeled standards. As deuterated and other isotope labelled internal standards have similar extraction recovery, ionisation response and matrix effect they also improve the accuracy of the quantification method. They reduce chromatography time, and make assays more robust by increasing throughput and lowering rejection rates as well.
He also elaborated on the important aspects of Stable Isotopic Labelled Standards such as isotopic purity, parent mass interference, degree of labeling while selecting an isotopic standard, chemical stability of standards, label position, dealing with internal standards of bioassay, etc.