You are here:
An Inexpensive Autosampler to Maximize Throughput for an Ion Source that Samples Surfaces in Open Air
Citation:
GRANGE, A. H. An Inexpensive Autosampler to Maximize Throughput for an Ion Source that Samples Surfaces in Open Air. INTERNATIONAL JOURNAL OF ENVIRONMENTAL FORENSICS 9(2 & 3):127-136, (2008).
Impact/Purpose:
Provide state-of-the-science sampling, analysis, separation, and detection methods to allow rapid, accurate field and laboratory analyses of contaminated soils, sediments, biota, and groundwater to support Superfund clean-up decisions. Apply state-of-the-science methods in chemical analysis and data interpretation (e.g., mass spectral interpretation) to actual problems of OSWER, the Regions, and the States, in cooperation with the Las Vegas Technical Support Center as well as by direct contacts with Regional and State employees. Provide technical advice and guidance to OSWER using the environmental chemistry expertise (e.g., mass spectrometry, analytical methods development, clean-up methodology, inorganics, organometallics, volatile organics, non-volatile organics, semi-volatile organics, separation technologies, etc.) found within the branch.
Technical research support for various projects initiated either by Regions/Program Offices or ECB scientists. While these efforts will support the Regions and Program Offices, they cannot be predicted or planned in advance, and may serve multiple duty (e.g., solve real-world problems, serve to ground-truth analytical approaches that ECB is developing, transfer new technology). Many of the activities in this task support requests involving enforcement decisions and therefore are categorized as "environmental forensics".
Description:
An autosampler was built to pull cotton swab heads mounted into a 3-foot long, square Al rod in ambient air through the He ionizing beam of a Direct Analysis in Real Time (DART) ion source interfaced to an orthogonal acceleration, time-of-flight mass spectrometer. The cost of the N-scale model railroad components, motor, wooden support structure, and other materials was less than $250. For five sets of 76 swabs (72 dipped into one of three analyte solutions and four into a PEG calibrant solution) %RSDs of 18.5% to 21.3% were obtained for the chromatographic peak areas from each swab in the ion chromatograms of the protonated molecular ions. Maximum to minimum ratios of the areas were between 2.22 and 2.71. An optimum speed of 0.2 cm/s provided mass spectra for all 76 swabs in a single data file acquired in 7.5 min. Mass calibration against mass spectra from the PEG swabs in positions 1, 26, 51 and 76 provided exact masses of analyte ions always accurate to within 1 mmu and usually accurate to within 0.5 mmu.