Applications of Infrared Spectroscopy in Analysis of Organic Aerosols

Abstract

This paper reviews the studies of using FTIR to investigate the components of aerosols produced in smog chamber experiments and collected in atmosphere. The fact that aerosols are mixture of small amount of countless individual compounds makes the analysis of aerosol constituents very challenging. Although a number of advanced instruments have been applied to the chemical characterization of aerosol components, the majority of aerosol components, particularly the organics, remain unknown. Being supplemental to the traditional quantitative instruments, FTIR has been recently used either individually or combining with other analytical instruments to characterize the components of aerosol particles. This paper aims to show how FTIR is applied to analysis of organic aerosols in current literature and to summarize the FTIR characteristic peak frequencies that are widely seen in the FTIR measurement of organic aerosols. It will be greatly helpful to researchers whose studies are focused on the analysis of aerosol components.

Photobleaching and Recovery Kinetics of a Palette of Carbon Nanodots Probed by In Situ Optical Spectroscopy

“…At lower wavenumbers, we found a third broad band at 1580 cm –1 and signals at 1345 and 1415 cm –1 , which can be respectively attributed to C–N stretching and N–H bending in amines, confirming successful N-doping of the CD surface. 58 Again, these N-related signals are clearly distinguishable in CU25 and CZAU but less resolved in CT and CU2, where the concentration of N in the original precursors is much lower. Finally, a poorly structured band is found in the range 1000–1100 cm –1 , likely ascribable to C–OH stretching.…”

“…A broad CO stretching band at 1690 cm –1 and a weaker contribution at 1710 cm –1 are prominent in the spectra of CU25 and CZAU, but CO vibrations in this region also appear in lower intensity in the CT sample and can be barely discerned in the CU sample. At lower wavenumbers, we found a third broad band at 1580 cm –1 and signals at 1345 and 1415 cm –1 , which can be respectively attributed to C–N stretching and N–H bending in amines, confirming successful N-doping of the CD surface . Again, these N-related signals are clearly distinguishable in CU25 and CZAU but less resolved in CT and CU2, where the concentration of N in the original precursors is much lower.…”

“…The narrower features at ≈3200, 3400, and 3450 cm –1 that we attribute to NH stretching are only observed in CU25 and CZAU. A broad C=O stretching band 58 at 1690 cm –1 and a weaker contribution at 1710 cm –1 are prominent in the spectra of CU25 and CZAU, but C=O vibrations in this region also appear in lower intensity in the CT sample and can be barely discerned in the CU sample. At lower wavenumbers, we found a third broad band at 1580 cm –1 and signals at 1345 and 1415 cm –1 , which can be respectively attributed to C–N stretching and N–H bending in amines, confirming successful N-doping of the CD surface.…”

“…Despite CU2 and CU25 having the same precursors, although in different proportions, their ATR spectra are quite different: in particular, the CU2 spectrum is poorly resolved, but it is possible to recognize the CO features and the peaks involving C–N and N–H stretching. SAFD spectrum is equally unresolved: its main peaks are at ≈1530 and 1570 cm –1 , likely arising from the nitroaromatic rings . Vice versa, the hydrophobic sample CD49 shows very sharp and strong IR peaks in the spectral region at 600–1000 cm –1 and at 2800–3000 cm –1 .…”

Aging of atmospheric aerosols and the role of iron in catalyzing brown carbon formation

“…Examples of 'offline' techniques used to identify organic functional groups are Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). The application of infrared spectroscopy to the detection and quantication of functional groups in water soluble organic particles from the smog chamber and eld studies has been reviewed by Reggente et al 149 and Gao et al 150 The identication and quantication of functional groups in organic aerosol particles using NMR Spectroscopy was reviewed by Duarte and Duarte. 39,151 Classes of identied organic functional groups include aliphatic, alkene, aromatic, and carbonyl carbon, in addition to alcohols, organosulfates and amines.…”