UPLC provides faster, more sensitive chromatographic separations compared to HPLC. It works by using smaller particle sizes (<2.5um) in the column packing which allows for higher pressure and flow rates based on the van Deemter equation. This provides benefits like reduced run times, decreased sample volume needs, and improved resolution. However, it also requires more robust instrumentation to handle the increased pressures and columns have reduced lifespan. UPLC has applications in fields like pharmaceutical analysis, metabolomics, and impurity profiling due to its enhanced resolution and sensitivity capabilities.