Special Issues-06-01-2010

The motivation for the development of an instrument for transmission Raman measurements is described. The basic instrumentation and the first results from a commercial system are provided. Transmission Raman spectroscopy (TRS) performance is compared to and contrasted with that of a confocal Raman microscope.

Recent developments in photonics are finally making Raman instrumentation accessible to larger basic laboratories.

Today's Raman spectrometers are more capable than ever before. The seeds of innovation in filter, laser, and CCD technology have produced a crop of instruments that are fast, sensitive, and robust. This is good news because scientists are constantly bombarded with challenging problems that require the top performance from their instruments.

Surface-enhanced Raman spectroscopy (SERS) has been studied extensively over the last few decades with many advances in preparation of SERS substrates and coatings. While the bulk of the research in SERS substrate preparation has been devoted to pushing detection limits to higher sensitivity for measurement of single samples, the application of SERS to high-throughput analysis has been largely ignored. In this article, we present the use of commercially available SERS-coated microtiter plates in a dedicated Raman microtiter plate reader, enabling high-throughput trace analysis measurements. This article also describes the SERS substrate, the high-throughput plate reader, and preliminary results from samples representing trace analysis of explosives, nerve agents, pharmaceuticals, and biological compounds.

A better understanding of the micro- and nanostructures of cellulose fiber composition before and after various chemical treatments, together with the distribution of bleaching additives to the final paper composition, is essential for further improvements of paper properties. Confocal Raman imaging is a valuable tool for such studies, as it reveals not only optical information but also information regarding the 3D distribution of the chemical compounds in the submicrometer range. In the paper surface finishing process, additional surface roughness parameters can be measured by combining confocal Raman microscopy with atomic force microscopy. Such combined analytical microscopes allow a direct linking between high-resolution imaging and chemical identification of various species on a surface.