Tandem Raman and Elemental Aerosol Spectrometer (TREAS) for Near-Real-Time Aerosol Chemical Speciation

Details

• Journal Article:
  Analytical Chemistry
• Personal Author:
  Kulkarni, Pramod ; Pugh, Nicholas ; Zervaki, Orthodoxia ; Rishi, Kabir ; Devarakonda, Surendra B.
• Description:
  Current methods for quantifying aerosol chemical exposures rely primarily on filter-based collection and off-line laboratory analysis, resulting in significant delays in chemical risk assessment. We describe the development and evaluation of the Tandem Raman and Elemental Aerosol Spectrometer (TREAS), a compact instrument designed for the near-real-time measurement of trace elemental and molecular speciation in workplace atmospheres. TREAS employs an automated, cyclical "collection-analysis-ablation" scheme, in which aerosols are focused onto a dry spot, analyzed by Raman spectroscopy (RS), and subsequently ablated by pulsed spark discharges for elemental quantification via spark emission spectroscopy (SES). Laboratory evaluation using occupationally relevant aerosols in the PM2.5 size fraction, specifically crystalline silica (a-quartz) and titanium dioxide (TiO2), demonstrated mass limits of detection (LOD) that were significantly lower than those of standardized X-ray diffraction and infrared methods. The LODs for a-quartz were 420 ng (RS) and 900 ng (SES), while LODs for TiO2 were 155 ng (RS) and 250 ng (SES). Beyond quantification, the tandem approach provided complementary chemical insights: while SES quantified trace elements, RS can successfully distinguish between the chromium(VI) and chromium(III) oxidation states in welding fumes. The study demonstrates the potential of TREAS to provide high-sensitivity, automated, and analyte-specific monitoring of complex aerosol exposures in near real-time.
• Subjects:
  Occupational Health Particulate Matter Safety
• Keywords:
  Analytical chemistry; Aerosols; Spectroscopes; Trace analysis; Analytical instruments; Measurement equipment; Emerging technology; Particulate sampling methods; Mixed exposures; Air sampling techniques
• Source:
  Anal Chem 2026 Apr; 98(16):11923-11934
• ISSN:
  0003-2700
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; South Dakota ; Chicago Region [OSHA] ; Denver Region [OSHA]
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  12 pdf pages
• Volume:
  98
• NIOSHTIC Number:
  nn:20071471
• Contact Point Address:
  Pramod Kulkarni, Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH), 1090 Tusculum Avenue, Cincinnati 45226, Ohio, United States
• Email:
  PSKulkarni@cdc.gov
• Federal Fiscal Year:
  2026
• Peer Reviewed:
  True
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:0f3f6cfae7e3b9f2703e7e0d4843150bd7b1a2cce1564d8005e9eff5a3c77e3b46a8563023c56f4b0429c592dc69d94d24493865489d0132a4e671a63a256e30
• Download URL:
  https://stacks.cdc.gov/view/cdc/259069/cdc_259069_DS1.pdf
• File Type:
  [PDF - 3.54 MB ]