DIFFUSE-REFLECTANCE INFRARED FOURIER-TRANSFORM SPECTROSCOPY - NEW TECHNIQUE OF SAMPLE PREPARATION

A new technique of measurement of the diffuse-reflectance infrared FT spectra based on the preparation of a cylinder from the mixture of the sample and powdered KBr under pressure of about 5.85 MPa, has Seen te sted. During the measurement, the axis of the formed cylinder is perpe ndicular to the direction of the incident light. A repeatability of th e measurement of selected bands and also of the background was investi gated for hydroquinone, nicotinamide. silica gel, rice, tea and also l yophilized human aqueous humour. The relative standard deviations of l og(1/R) showed a dependence on the character of the measured compound, but in general were comparable or slightly better than those obtained by the standard method of loosely packed cups. The values were better than 1.5% in the most cases. The main advantage of the proposed techn ique lies in its simplicity and rapidity of obtaining statistically si gnificant data. (C) 1997 Elsevier Science B.V.