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Evaluation of split/splitless operation and rapid heating of a multi-bed sorption trap used for gas chromatography analysis of large-volume air samples.

Authors
Whiting-JJ; Sacks-RD
Source
J Sep Sci 2006 Feb; 29(2):218-227
NIOSHTIC No.
20029730
Abstract
The effects of split-flow operation and rapid trap heating on injection-plug widths from an electrically heated, microscale, multibed sorption trap were evaluated. The sorption trap has been designed to quantitatively collect volatile organic compounds from large-volume vapor samples and inject them into a gas chromatograph. Previous trap designs resulted in injection-plug widths of typically a second or more, and this significantly degraded chromatographic resolution, particularly for early-eluting sample components and for high-speed separations. Injection-plug widths are determined by the heating rate of the trap during sample desorption and the volumetric flow rate of carrier gas through the trap. The effects of the heating rate of the trap and carrier gas velocity through the trap on the injection-plug widths of pentane, octane, and undecane were studied. Carrier gas velocity through the trap was increased by splitting the flow coming from the trap between the column and a vent. This decreases transport time from the trap to the column, and thus decreases injection-plug widths. The heating rate for the trap was increased by increasing the applied voltage in the range from 4 to 30 V. Increasing the heating rate decreases the time required to desorb the analytes from the sorbent bed, thus decreasing injection-plug width. Injection-plug widths as small as 89, 210, and 520 ms were obtained in the split mode with very fast heating rates for n-pentane, noctane, and n-undecane, respectively. The effect of split ratio on resolving power, peak height, and peak width was also evaluated.
Keywords
Gas-chromatography; Air-samples; Air-sampling; Heat; Organic-compounds; Vapors; Air-quality-monitoring; Air-quality-measurement; Sampling; Organic-vapors
CODEN
JSSCCJ
Publication Date
20060201
Document Type
Journal Article
Email Address
rdsacks@umich.edu
Funding Type
Grant
Fiscal Year
2006
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003692
Issue of Publication
2
ISSN
1615-9306
Source Name
Journal of Separation Science
State
MI
Performing Organization
University of Michigan, Ann Arbor
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