New approach for near-real-time measurement of elemental composition of aerosol using laser-induced breakdown spectroscopy

Details

• Personal Author:
  Birch, M. Eileen ; Diwakar P ; Kulkarni PS
• Description:
  A new approach has been developed for making near-real-time measurement of elemental composition of aerosols using plasma spectroscopy. The method allows preconcentration of miniscule particle mass (pg to ng) directly from the sampled aerosol stream through electrostatic deposition of charged particles (30-900 nm) onto a flat-tip microneedle electrode. The collected material is subsequently ablated from the electrode and monitored by laser induced breakdown spectroscopy. Atomic emission spectra were collected using a broadband spectrometer with a wavelength range of 200-980 nm. A single-sensor delay time of 1.3 micros was used in the spectrometer for all elements to allow simultaneous measurement of multiple elements. The system was calibrated for various elements including Cd, Cr, Cu, Mn, Na, and Ti. The absolute mass detection limits for these elements were experimentally determined and found to be in the range of 0.018-5 ng. The electrostatic collection technique has many advantages over other substrate-based methods involving aerosol collection on a filter or its focused deposition using an aerodynamic lens. Because the particle mass is collected over a very small area that is smaller than the spatial extent of the laser-induced plasma, the entire mass is available for analysis. This considerably improves reliability of the calibration and enhances measurement accuracy and precision. Further, the aerosol collection technique involves very low pressure drop, thereby allowing higher sample flow rates with much smaller pumps - a desirable feature for portable instrumentation. Higher flow rates also make it feasible to measure trace element concentrations at part per trillion levels. Detection limits in the range of 18-670 ng m(-3) can be achieved for most of the elements studied at a flow rate of 1.5 L min (-1) with sampling times of 5 min. [Description provided by NIOSH]
• Subjects:
  Aerosols Cadmium Chromium Manganese Nitrates Occupational Health Safety Spectrum Analysis
• Keywords:
  Aerosol-generators Aerosol-particles Aerosol-sampling Ammonium-compounds Analytical-instruments Cadmium-compounds Chromium-compounds Copper-compounds Electrostatic-atomizers Electrostatic-fields Lasers Manganese-compounds Measurement-equipment Sampling Sampling-equipment Sampling-methods Sodium-compounds Spectrographic-analysis Spectroscopes

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• ISSN:
  0278-6826
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DART - Division of Applied Research and Technology
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  316-332
• Volume:
  46
• Issue:
  3
• NIOSHTIC Number:
  nn:20039872
• Citation:
  Aerosol Sci Technol 2012 Mar; 46(3):316-332
• Contact Point Address:
  Pramod Kulkarni, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, MS R7, Cincinnati, OH 45226, USA
• Email:
  PSKulkarni@cdc.gov
• CAS Registry Number:
  Cadmium (CAS RN 7440-43-9) ; Chromium (CAS RN 7440-47-3) ; Copper (CAS RN 7440-50-8) ; Manganese (CAS RN 7439-96-5) ; Sodium chloride (CAS RN 7647-14-5)
• Federal Fiscal Year:
  2012
• NORA Priority Area:
  Manufacturing
• Peer Reviewed:
  True
• Source Full Name:
  Aerosol Science and Technology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:710c8f8fd5389786186dd41967160c0e4572fc9eeede722feb2f19a5a91215722a5d968c18182a8710d713b723a154deb714abaff53eb899814f3e7243ce7fac
• Download URL:
  https://stacks.cdc.gov/view/cdc/192936/cdc_192936_DS1.pdf
• File Type:
  [PDF - 760.24 KB ]