Surface Science- The primary motivation for identifying surface structures is to determine the relationship between the surface species, their architecture and the under-laying surface and subsurface. Materials scientists and engineers have used Raman spectroscopy to study how surfaces and interfaces interact for various chemical and bio-chemical processes. It is desirable to understand the number and type of chemical bonds that are formed as films or bio-films are deposited on a substrate and how these processes can be tailored and controlled in order to optimize the surface and interfacial properties. Our customers are using our instrumentation in various fields of surface science, such as bio-engineering, polymer films, colloidal interfaces, surfactants, adsorption on metal oxides, and electrochemical deposition.

Low level Detection (SERS)- Although Raman spectroscopy is information rich, it is considered to have poor efficiency in comparison to luminescent processes (e.g., the lowest limits of detection reported for Raman are parts-per-million). Nevertheless, there has been a renewed interest in Raman techniques in the past two decades owing to the discovery of the surface-enhanced Raman scattering (SERS) effect, which results from the adsorption of molecules on nano-textured metallic surfaces. The large SERS enhancement (10⁶) was first reported by Van Duyne. Since this discovery, SERS has been used to detect and characterize a variety of chemical and biological processes. SERS has been used for medical diagnostics, DNA sequencing, biological imaging, the detection of environmental pollutants, adsorption processes at electrochemical surfaces and film growth studies, among others. The Inspector Raman and Advantage Series spectrometers have been coupled with derivatized SERS particles for the detection bio-molecules and surface characterization.

Inorganic Chemistry - Raman is one of the few analytical methods that can analyze both elements and molecules. Raman has been used to study several elements such as various forms of carbon (graphite, diamond and fullerene), sulfur and nitrogen. At a recent American Chemical Society (ACS) conference, it was reported that over 300 publications per year were devoted to using Raman spectroscopy in catalysis research alone. Raman spectroscopy is used to validate the preparation of catalyst and monitor the kinetics of transformation of new materials that are affected by catalyst or catalyst supports. Some common examples are monitoring zeolite and Bismuth formation. Several types of metal oxides are used as catalyst supports, and Raman has been used to determine their structure under hydrated and unhydrated conditions.

Raman has been used in organometallic chemistry to monitor the synthesis of catalysts and other components in inert environments. Characterizing these compounds is sometimes difficult because they can be exposed to oxygen or moisture when a sample is extracted for analysis. The Inspector Raman is ideal for this application because it can monitor reactions and the formation of products through vacuum reaction flasks. And because of the Inspector Raman’s small size and wireless communication features, it can be transported through the airlock of a standard glove box for analysis of products in inert environments.

Organic Chemistry - The Inspector Raman has been used to monitor microwave assisted reactions, combinatorial micro reactions and common organic and inorganic reactions. Synthetic reactions are usually carried out in glass containers such as round-bottom flasks, test tubes and vacuum line containers. Since Raman is a focusing technique it is important that the focal point is optimized in the solution, and not on the glass interface. The focal point of the Inspector Raman is easily focused into the solution by a simple manual adjustment. In the example at right, we show an example of how glass can interfere while measuring acetone solvent in a round bottom flask. For this experiment, no sampling attachments were used, the Raman was collected using the standard sampling nose of the Inspector Raman. As the distance from the flask is increased, glass interference is pronounced and eventually overwhelms the spectrum. Reaction containers are easily accommodated by the Inspector Raman, and quality spectra are obtained by placing the nozzle against or near the glass surface.

In the last example, we display continuous spectra obtained by monitoring formation of an imidazole. In less than two minutes, several quality spectra are obtained in order to monitor the formation of the final product.