NEAR-IR MULTIPLEX BANDPASS SPECTROMETER UTILIZING POLYMER FILTERS

A simple near-infrared spectrometer is described that utilizes ordinar y polymer sheets as near-IR spectral filters. Examples of filter mater ials include polymethyl methacrylate, polyvinyl chloride (PVC), and or ganic solutions immobilized in a PVC matrix. The polymers were prepare d by using solvent-molding techniques as well as with a thermoforming process. Each filter substance passes multiple bands of near-IR radiat ion. The performance of the spectrometer is demonstrated in selected q uantitative and qualitative near-IR analytical applications. The appli cability of the designed multiplex bandpass spectrometer in determinin g trace levels of water in methanol, dimethyl sulfoxide, and propylene glycol is examined. Additionally, the utility of the spectrometer in the determination of glucose concentration in aqueous solutions is stu died.