N-Isobutyryl-L-cysteine is widely used in chiral derivatization to separate and analyze enantiomers in complex mixtures. It reacts selectively with chiral compounds, forming diastereomers that can be easily distinguished using techniques like HPLC or GC. This is particularly useful in pharmaceutical analysis to ensure the purity and efficacy of enantiomerically active drugs. It also aids in studying stereochemistry in biochemical processes, helping researchers understand the behavior of chiral molecules in biological systems. Its application extends to food and environmental analysis, where it helps detect and quantify chiral contaminants or additives.