Design considerations for near-infrared filter photometry: effects of noise sources and selectivity.

Optimal filter design of two-channel near-infrared filter photometers is investigated for simulated two-component systems consisting of an analyte and a spectrally overlapping interferent. The degree of overlap between the analyte and interferent bands is varied over three levels. The optimal design is obtained for three cases: a source or background flicker noise limited case, a shot noise limited case, and a detector noise limited case.

Scattering and absorption effects in the determination of glucose in whole blood by near-infrared spectroscopy.

Optical properties of whole bovine blood are examined under conditions of different glucose loadings. A strong dependency is established between the scattering properties of the whole blood matrix and the concentration of glucose. This dependency is explained in terms of variations in the refractive index mismatch between the scattering bodies (predominately red blood cells) and the surrounding plasma.

Molar absorptivities of glucose and other biological molecules in aqueous solutions over the first overtone and combination regions of the near-infrared spectrum.

Molar absorptivities are measured for water, glucose, alanine, ascorbate, lactate, triacetin, and urea in the near-infrared spectral region at 37 degrees C. Values are based on the Beer-Lambert law and cover the first overtone (1550-1850 nm; 6450-5400 cm(-1)) and combination (2000-2500 nm; 4000-5000 cm(-1)) spectral windows through aqueous media. Accurate calculations demand accounting for the impact of water displacement upon dissolution of solute.

Determination of glucose concentration in a scattering medium based on selected wavelengths by use of an overtone absorption band.

A method and device for measuring glucose concentration in a scattering medium have been developed. A spectral range of 800-1800 nm is considered for wavelength selection because of its deeper penetration into biological tissue and the presence of a glucose absorption band. An algorithm based on selected wavelengths is proposed to minimize interference from other components.