Analytical chemistry is the science of qualitative and quantitative analysis, which is employed in many fields: pharmaceutical industry, medical research, and food science. These are only a few examples in which analytical techniques are required. A reliable, precise measurement is dependent on an accurate, sensitive and robust method as well as the nature and complexity of the matrices analyzed and the concentration and stability of the analyte. This book describes how new materials are applied to improve the sensitivity of analytical platforms and diagnostic tests. Hydrogel nanoparticles and microparticles composed of TiO2 are proposed for protein analysis in biological matrices. Absorbing properties of hydrogel nanoparticles in solution are exploited to capture and concentrate low molecular weight proteins in biological fluids, while TiO2 microparticles are used for phopshoproteins enrichment. Additionally, adsorbent material (C18) held tightly in an inert membrane is used to sample airborne organic molecules.