Sampling and Raman confocal microspectroscopic analysis of airborne particulate matter using poly(dimethylsiloxane) solid-phase microextraction fibers

Our plain-English summary of Sampling and Raman confocal microspectroscopic analysis of airborne particulate matter using poly(dimethylsiloxane) solid-phase microextraction fibers, by M. Odziemkowski, J.A. Koziel, D.E. Irish, et al (Analytical Chemistry, 2001).

The study

• Authors: M. Odziemkowski, J.A. Koziel, D.E. Irish, J. Pawliszyn
• Journal: Analytical Chemistry
• Published: 2001;73(13):3131-9
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Commercial poly(dimethylsiloxane) (PDMS) 7-microm solid-phase microextraction (SPME) fibers were used for sampling and Raman spectroscopic analysis of a tailpipe diesel exhaust, candle smoke, cigarette smoke, and asbestos dust. Samples were collected via direct exposure of the SPME fiber to contaminated air. The mass loading for SPME fibers was varied by changing the sampling time. Results indicate that PDMS-coated fibers provide a simple, fast, reusable, and cost-effective air sampling tool for airborne particulates. The PDMS coating was stable; Raman bands of the PDMS coating were observed exactly at the same wavenumber positions before and after air sampling. Raman spectroscopic analysis resulted in identification of several characteristic bands allowing chemical speciation of particulates. The advantage of the SPME fiber is the open bed geometry allowing for application of various spectroscopic methods of particulate analysis. This paper describes the first-ever combined application of SPME technology with Raman confocal microspectroscopy for sampling and analysis of airborne particulates. Advantages of the combination of solid-phase microextraction and Raman microspectroscopy for airborne particulate analysis are discussed. Challenges associated with combined SPME sampling and Raman analysis of single particles are also described.

In plain English

This was a laboratory methods study, not a health study. The authors tested whether commercial solid-phase microextraction (SPME) fibers coated with poly(dimethylsiloxane) could collect airborne particles for confocal Raman microspectroscopy. They sampled diesel truck exhaust, tobacco smoke, oil lamp smoke, and air in a closed, shaken vial holding an asbestos mineral sample. Under the microscope, that sample showed white material possibly chrysotile and brown material possibly amosite. Particles from the asbestos vial gave Raman bands most closely resembling chrysotile, the strongest at 391 and 694 cm-1. Not all chrysotile bands were detected, which the authors said may reflect signal loss in confocal mode. A glass fiber stripped of its coating failed to sample asbestos. The diesel and tobacco samples showed graphitic carbon. Quartz appeared only on cold-engine diesel samples; the authors judged it not linked to fuel combustion and most probably sand blown onto the fiber by the exhaust. Lamp smoke particles had a band suggesting a polycyclic aromatic hydrocarbon. The authors concluded that the coated fibers performed very well in sampling fuel exhausts and asbestos dust.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory analytical methods (feasibility) study combining SPME air sampling with confocal Raman microspectroscopy
• Who was studied: No people were studied. Samples were air from a closed vial holding an asbestos mineral sample from the University of Waterloo Department of Earth Sciences, exhaust from a 1998 diesel truck, cigarette smoke and oil lamp smoke, collected at the University of Waterloo, Ontario, Canada
• Exposure: An asbestos mineral sample in fiber form showing white material that might be chrysotile and brown material that might be amosite. It was sampled from the air of a shaken, septum-closed 40-mL vial without the SPME fiber touching the bulk mineral. Diesel exhaust, tobacco smoke and oil lamp smoke were also sampled.
• Main results:
  • The asbestos particles collected on the SPME fiber coating most closely resembled chrysotile
  • The strongest Raman bands from the asbestos particle were at 391 and 694 cm-1
  • Asbestos sampling with a bare glass fiber (PDMS coating removed) was not successful
  • Cold-engine diesel exhaust samples showed carbonaceous material from incomplete diesel combustion
  • Quartz particles were detected only in the cold-engine diesel samples. The authors judged that the quartz was not linked to diesel fuel combustion and was most probably quartz sand blown onto the fiber by the exhaust gases.
  • A 1-minute exposure to hot-engine diesel exhaust gave no measurable Raman signal
  • In tobacco smoke samples, graphitic carbon was the only species Raman could detect
  • Particles from oil lamp smoke had bands suggesting a polycyclic aromatic hydrocarbon
  • In all investigated cases the PDMS coating was stable and inert toward the analytes
• The authors' conclusion: The authors concluded that the SPME fiber coating performed very well in sampling fuel exhausts and asbestos dust
• Limitations the authors state:
  • The confocal mode caused severe signal loss, which may explain why not all characteristic chrysotile bands were detected
  • With limited data, positive identification of the oil lamp particles' chemical composition was very difficult
  • Sample fluorescence could not be fully eliminated despite confocal measurement
  • Laser-induced desorption was observed in some situations, so combining Raman and GC/MS on a single air sample needs further research

Topics

Medical terms in this study, explained in our Lexicon: Air Sampling.

Related studies

• Coupling SEM-EDS and confocal Raman-in-SEM imaging: A new method for identification and 3D morphology of asbestos-like fibers in a mineral matrix — G. Wille, D. Lahondere, et al. (2019)
• Pulmonary oxidative stress, inflammation and cancer: respirable particulate matter, fibrous dusts and ozone as major causes of lung carcinogenesis through reactive oxygen species mechanisms — A. Valavanidis, T. Vlachogianni, et al. (2013)
• Assessing truck driver exposure at the World Trade Center disaster site: personal and area monitoring for particulate matter and volatile organic compounds during October 2001 and April 2002 — A.S. Geyh, S. Chillrud, et al. (2005)
• A comparison of asbestos and urban particulate matter in the in vitro modification of human alveolar macrophage antigen-presenting cell function — R.F. Hamilton, A. Holian, et al. (2004)
• Risk of human health by particulate matter as a source of air pollution--comparison with tobacco smoking — M. Enomoto, W.J. Tierney, et al. (2008)
• Demolition of high-rise public housing increases particulate matter air pollution in communities of high-risk asthmatics — S. Dorevitch, H. Demirtas, et al. (2006)

Browse return to medical research.