IEF Sample Buffer is primarily used in isoelectric focusing (IEF) to prepare protein samples for analysis. It helps in denaturing proteins, breaking disulfide bonds, and maintaining solubility during the IEF process. The buffer typically contains urea and a non-ionic detergent, which aid in unfolding proteins and preventing aggregation. It also includes reducing agents like DTT or β-mercaptoethanol to ensure proteins remain in their reduced state. This preparation is crucial for achieving accurate separation of proteins based on their isoelectric points in techniques such as 2D gel electrophoresis. Additionally, the buffer often contains carrier ampholytes to stabilize the pH gradient during focusing, enhancing resolution and reproducibility of results.