Hygroscopic Behavior of Substrate-Deposited Particles Studied by micro-FT-IR Spectroscopy and Complementary Methods of Particle Analysis

Journal Article · Fri Feb 01 04:00:00 EST 2008 · Analytical Chemistry, 80(3):633-642

DOI:https://doi.org/10.1021/ac701638r· OSTI ID:939018

Liu, Yong; Yang, Zhiwei; Dessiaterik, Yury; Gassman, Paul L; Wang, Hai; Laskin, Alexander

The application of Microscopic Fourier Transform Infrared (micro-FTIR) spectroscopy combined with complementary methods of particle analysis is demonstrated here for investigations of phase transitions and hygroscopic growth of micron-sized particles. The approach utilizes the exposure of substrate-deposited, isolated particles to humidified nitrogen inside a sample cell followed by micro-FTIR spectroscopy over selected sample area. Phase transitions of NaCl, sea salt, NaNO3 and (NH)4SO4 particles are monitored with this technique to evaluate its utility and applicability for particle hydration studies. The results are found in excellent agreement with literature data in terms of (a) reliable and reproducible detection of deliquescence and efflorescence phase transitions, (b) quantitative measurements of water-to-solute ratios in particles as a function of relative humidity, and (c) changes in the IR spectra resulting from phase transitions and changing relative humidity. Additional methods of particle analysis are employed to complement and assist in the interpretation of particle hygroscopicity data obtained from micro-FTIR measurements. The analytical approach and the experimental setup presented here are relatively simple, inexpensive, readily available, and therefore may be practical for hydration studies of environmental particles collected in both laboratory and field studies.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 939018
• Report Number(s): PNNL-SA-56555; 17808; 25430; KP1704020
• Journal Information: Analytical Chemistry, 80(3):633-642, Journal Name: Analytical Chemistry, 80(3):633-642 Journal Issue: 3 Vol. 80
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AMMONIUM SULFATES
Environmental Molecular Sciences Laboratory
FOURIER TRANSFORM SPECTROMETERS
HYGROSCOPICITY
INFRARED SPECTRA
PHASE TRANSFORMATIONS
SODIUM CHLORIDES
SODIUM NITRATES