Articles
Evaluation Of The Impact Of Container Interference For Bulk Material Authentication Using A Handheld Raman Spectrometer
November 18, 2009
•Poster: Evaluation Of The Impact Of Container Interference For Bulk Material Authentication Using A Handheld Raman Spectrometer
By Jeremy A. Linoski, Robert C. Brush, Robert L. Green, Wayne Jalenak, Christopher D. Brown, Ahura Scientific, Inc.
Recent instrumental advances have lead to commercial availability of several portable spectroscopic technologies, including handheld near-Infrared, mid-Infrared, and Raman. While laboratory vibrational spectroscopy has been a popular choice for raw material identification, widespread applicability of portable systems for material authentication has only recently been highlighted. Applicable sampling approaches are an important practical consideration when evaluating technologies for field (i.e. warehouses) raw material authentication. For example, mid-Infrared spectroscopy requires that a sample be first removed from its packaging in a clean environment to prevent possible contamination then subsequently prepared in a suitable form for analysis. Raman and near-Infrared (NIR) do not suffer from this difficulty as it is possible to analyze solids through packaging materials. Raman, as opposed to NIR, offers the additional capability to directly measure liquids in their containers.Ulmshneider, et. al. demonstrated that the presence of packaging can have a marked impact on features present in NIR spectra; however, they also concluded selective identification methods for packaged solids can be developed when appropriate chemometric data treatments are used. The authors failed to discuss the long-term difficulties encountered using NIR when either packaging thickness or type (polyethylene vs. polypropylene, etc.) are changed by the raw material supplier. Compton's early work using Raman to examine packaged goods demonstrated that spectroscopic contribution due to packaging was nearly negligible for the materials studied. In the present study, we expand upon these results and evaluate method robustness to changes in container packaging. To accomplish this, methods for several common solid and liquid raw materials were developed using a single reference spectrum collected on neat samples. The methods were then challenged by measuring the materials under different packaging arrangements including clear and amber glass, and single, double, and triple bagged samples.
Click Here To Download:•Poster: Evaluation Of The Impact Of Container Interference For Bulk Material Authentication Using A Handheld Raman Spectrometer
