By Ebatco
Confocal Raman Microscopy has many advantages over traditional Raman spectroscopy. For instance, in microscopy small areas of samples can be selected for data collection. The most prominent advantage, however, is the ability to obtain molecular information at different depths of transparent samples. Because of the confocal design of the microscope, any signal originating from the sample that is not in the focal plane of the microscope will not reach the detector. The WITec 300RA Confocal Raman Microscope (CRM) is used to obtain chemical and structural molecular information in the form of area maps or single point scans. The CRM is widely used for characterization purposes in the following industries: - Pharmaceutics - Medical Device - Semiconductors - Food and Beverage - Geology - Polymers - Chemical Analysis - Packaging - Failure Analysis - Art and Conservation - Forensics - Paints and Adhesives Typical Experimental Results Of all the types of imaging modes available on the 300RA CRM, perhaps the two most ubiquitous are depth scanning and chemical mapping. Typical data sets for each are shown below. Depth Scans Depth scans are essentially vertical cross sections of samples. The samples do not need to be prepared or microtomed in any particular manner, and often they can simply be placed directly onto the sample stage. The operator can then specify to what depth he or she wants to image. A typical depth scan is shown below. Layer thickness, layer uniformity, and layer identification can all be determined by these depth scans. Depth scan (left) and the corresponding spectrum of each area (right). Chemical Maps The 300RA CRM obtains chemical maps of surfaces by obtaining thousands of rapid point scans and then rasterizing all of the scans to generate an image. The user can then group spectra together using multivariate analyses, filter masks, or by creating basis spectra. The end result is a false-color composite image that indicates the 2D arrangement of the components. A typical area map is shown below. Chemical maps of three different areas of a sample. Each color corresponds to a distinct component of the sample. Applications Active Pharmaceutical Ingredient Identification and Concentration Contamination, Residue, and Failure Analysis Compound Distribution Counterfeit Identification Degree of Crystallinity Fiber Analysis Geologic Mineral Identification Ink Discrimination Laminate Film Characterization Partical Size and Distribution Polymer Blend Composition Polymorph Identification Powder Content and Purity Qualitative and Quantitiative Analysis Raw Material Verification Stress/Strain Mapping Instrument: WITec 300RA Confocal Raman Microscope (CRM) Instrument Key Specifications Excitation Source 50mW Yd:NAG laser, 532 nm Objective Lenses 10x, 20x, 50x, 100x Imaging Area Scan Size 150 um x 150 um Horizontal Spatial Resolution 360 nm Vertical Spatial Resolution 500 nm
