Abstract

The long-term reproducibility of a set of water spectra in the infrared region with cell thicknesses of less than 10 mu m was tested. With the application of a computer routine for subtraction in the range from 2600 to 1100 cm-1 and the use of additional phase and nonlinearity corrections, an accuracy better than one milliabsorbance unit (mAU) can be achieved, if the temperature is kept constant within a tenth of a degree or if a temperature correction factor is implemented in the subtraction routine. The subtraction of water from an aqueous protein solution reduces the spectral range for a correction to 2300-1800 cm-1.In this region the protein absorption, as derived from dry protein films, is constant, and because of the association band at 2125 cm-1 water exhibits good subtraction properties. However, the reduction of the spectral range for the water subtraction leads to an increase in the residual error to 12 mAU at 1650 cm-1. This standard deviation can be reduced to 6-7 mAU by applying a second subtraction range from 4000 to 3650 cm-1. A further reduction of this error to 3-5 mAU is obtained by implementing a constant ratio of the integrated intensities of the amide I and amide II bands in the procedure of subtracting water from aqueous protein solutions. The remaining inaccuracy is mainly

Infrared Spectroscopy of Biologic Materials in Aqueous Solutions

E. R. Blout and H. Lenormant
J. Opt. Soc. Am. 43(11) 1093-1095 (1953)

Temperature measurements of turbid aqueous solutions using near-infrared spectroscopy

Naoto Kakuta, Hidenobu Arimoto, Hideyuki Momoki, Fuguo Li, and Yukio Yamada
Appl. Opt. 47(13) 2227-2233 (2008)

Optical Constants in the Infrared for Aqueous Solutions of NaCl†

Marvin R. Querry, Richard C. Waring, Wayne E. Holland, G. Michael Hale, and William Nijm
J. Opt. Soc. Am. 62(7) 849-855 (1972)

Laser-induced fluorescence spectroscopy for phenol and intermediate products in aqueous solutions degraded by pulsed corona discharges above water

Daiyu Hayashi, Wilfred Hoeben, Geert Dooms, Eddie van Veldhuizen, Wijnand Rutgers, and Gerrit Kroesen
Appl. Opt. 40(6) 986-993 (2001)

Terahertz spectroscopy of thick and diluted water solutions

Fabio Novelli
Opt. Express 32(7) 11041-11056 (2024)