Crossed-beam apparatus for simultaneous spectrophotometric observation and microwave exposure of biochemical samples

Publisher Website
Google Scholar
Abstract
A spectrophotometer has been adapted for use as a simultaneous observation–exposure system for irradiation of biochemical samples by 1.7–2.6 GHz electromagnetic radiation. A waveguide applicator is mounted vertically in the sample compartment of a Cary 15 spectrophotometer such that the sample can be placed simultaneously in the light path and in a slot in the applicator. A standard 1‐cm path square cell contains the sample which is irradiated through the open top of the cuvette. Temperature of the sample and an unirradiated reference are monitored continuously without measurable interference from the microwave field. Temperature can be controlled within a few tenths of a degree between 15 ° and 40 °C, and an absorbed dose rate can be calculated using thermal measurement techniques. Microwave generator output and reflected power are monitored at all times. The frequency can be changed easily and standing waves minimized by adjusting a waveguide tuning section. The microwave energy within the basic frequency range can be applied as continuous wave or modulated. The quality of the absorption spectra is not measurably impaired, and the flexibility of the spectrophotometric technique remains intact.
Keywords