Sage Journals: Discover world-class research

Abstract

Infrared absorbance measurements through a gas flow cell are made with the closed-loop circulation of vapor/air mixtures equilibrated with the use of temperature-regulated aqueous solutions. Constant reproducible vapor pressures of organic solutes are established with the equilibrated aqueous solutions. The water solvent depresses the vapor pressure of the pure organic solutes of methanol, ethanol, isopropanol, acetone, and methyl ethyl ketone (MEK). Knowledge of the solution liquid mole fractions, the pure component vapor pressures, and the Wilson coefficients permits determination of the solute vapor pressures to within 2% accuracy. Reliable aqueous solution preparation requires only the correct weighings of pure constituent materials before mixing to achieve the targeted solute liquid mole fractions. Absorbances are measured for four of the five solutes over a range of seven concentrations and for MEK over four concentrations. These concentrations show the absorbance region of adherence to Beer's law with an experimental precision of approximately ±2% for the solutes studied. Absorptivities that are calculated from the Beer's law slope are compared to the available infrared absorbance data.

Keywords

Infrared absorbance Equilibrium vapor cell Quantitative infrared analysis FT-IR spectrometry

Get full access to this article

View all access options for this article.

References

Hammaker

R. M.

Fateley

W. G.

Chaffin

C. T.

Marshall

T. L.

Tucker

M. D.

Makepeace

V. D.

and Poholarz

J. M

, Appl. Spectrosc. 47, 1471 (1993).

Spartz

M. L.

Eldridge

J. S.

Hippie

G. D.

Reagen

W. K.

and Stock

J. W

, “Industrial Applications of Open-path Fourier Transform Infrared Spectroscopy”, in SPIE Proceedings of the 9th International Conference on Fourier Transform Spectroscopy, Vol. 2089, Calgary, Alberta, Canada (1993), p. 462.

Kroutil

R. T.

Combs

R. J.

Knapp

R. B.

and Small

G. W

, Appl. Spectrosc. 48, 724 (1994).

Bangalore

A. S.

Small

G. W.

Combs

R. J.

Knapp

R. B.

and Kroutil

R. T

, Anal. Chim. Acta 297, 387 (1994).

Monfre

S. L.

and Brown

S. D

, Appl. Spectrosc. 46, 1699 (1992).

Xiao

and Levine

S. P

, Anal. Chem. 65, 2262 (1993).

Hanst

P. L.

, Appl. Opt. 17, 1360 (1978).

Nelson

G. O.

, Gas Mixtures: Preparation and Control (Lewis Publishers, London, 1992).

Rhykard

C. L.

Jr. Cushman

J. H.

and Low

P. F

, J. Colloid Interface Sci. 139, 593 (1990).

10.

Wilson

G. M.

, J. Am. Chem. Soc. 86, No. 2, 127 (1964).

11.

Gmehling

and Onken

, Vapor Liquid Equilibrium Data Collection, Vol. I, Part 1 (DECHEMA, Frankfurt/Main 1977); with Arlt

, Part 1a (1981); with Rarey-Nies

J. R.

, Part 1b (1988).

12.

Kuehl

, Spectroscopy 4, No. 1, 30 (1989).

13.

Hirata

Ohe

and Nagahama

, Computer Aided Data Book of Vapor-Liquid Equilibria (Kodansha Limited, Elsevier Scientific Publishing Company, Tokyo, Japan, 1975).

14.

Hanst

P. L.

and Hanst

S. T

, Infrared Spectra for Quantitative Analysis of Gases, QASpec Spectra Library (Infrared Analysis Inc., Anaheim, California, 1996).

15.

Park

, Appl. Opt. 21, 1356 (1982).

16.

Sprouse

J. F.

, Quantitative Spectral Database, Interact Vers. 1.1 (Sprouse Scientific Inc., Paoli, Pennsylvania, 1991).

17.

Quantitative Infrared Vapor Phase Spectra, EMTIC Extractive Technologies FT-IR Spectral Data Base (U.S. EPA, Research Triangle Park, North Carolina, 1992).

18.

Mark

and Workman

, Statistics in Spectroscopy (Academic Press, Boston, Massachusetts, 1991), p. 61.

Equilibrium Vapor Cell for Quantitative IR Absorbance Measurements

Abstract

Keywords

Get full access to this article

References