The Haes group synthesizes noble metal nanostructures and subsequently modifies their surfaces with perm-selective surface chemistries for the direct and quantitative detection of small molecules and metabolites. Surface enhanced Raman spectroscopy (SERS) is used to directly detect the small molecules while novel surface layers facilitate molecular transport and recognition specificity. These materials and detection tools are integrated with microscale platforms (i.e. capillary electrophoresis) for the ultimate analysis of small volumes of samples in complex matrices. Our research emphasizes connections between the synthesis and physical properties of these nanomaterials to resulting technological applications and advances in biological and environmental applications.