Near-Infrared Spectroscopy as a Useful Tool for Analysis in Solution in Common Organic Solvents
Author: Iwamoto, Reikichi1
Source: Applied Spectroscopy, Volume 63, Issue 3, Pages 68A-86A and 261-380 (March 2009) , pp. 354-362(9)
Publisher: Society for Applied Spectroscopy
Abstract:
In the present paper we report that near-infrared spectroscopy is a useful tool for analyzing solutes in solution in common organic solvents. This is because the near-infrared absorptions of the solvent are not so strong as to disturb the separation of the characteristic near-infrared bands, by subtraction, of the solute. To demonstrate this capability, we first showed that the near-infrared absorptions of heptane and toluene, each of which represents aliphatic or aromatic solvents, do not significantly affect the noise level of the difference spectrum, in which the near-infrared spectrum of a solute is to be separated by subtraction. Second, we showed that the characteristic near-infrared absorptions of 1-heptene as a solute were well separated from the spectrum of the solution in heptane and toluene. Four of the five indicator bands of 1-heptene were recognizable and sufficiently detected at the almost limiting concentration of 0.1% (v/v) in both solvents. The minimum magnitude of the detectable signal is discussed in terms of the signal-to-noise ratios of the indicator bands. As an application, we investigated the interaction properties of a C≡CH group of 1-heptyne from the CH stretching fundamental, combination, and overtone bands in the pure liquid and in solution in three solvents at various concentrations.Keywords: INFRARED SPECTROSCOPY; IR SPECTROSCOPY; NEAR-INFRARED SPECTROSCOPY; NIR SPECTROSCOPY; SOLUTION ANALYSIS; NOISE; HEPTANE; TOLUENE; 1-HEPTENE; ACETYLENE; HYDROGEN BONDING
Document Type: Research article
DOI: 10.1366/000370209787598942
Affiliations: 1: NIRS Institute of Water, Yuyamadai 2-7-10, Kawanishi, Hyogo 666-0137, Japan

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