TITLE
Comparison of a Modified VOST Sampling Method to Method 0030

AUTHOR(S)
J. F. McGaughey, J.T. Bursey, R.G. Merrill, Jr., Radian Corporation
M. D. Jackson, L.D. Johnson, R.G. Furest, EPA

PERFORMING ORGANIZATION NAME AND ADDRESS
Radian Corporation
P.O. Box 13000
Research Triangle Park, NC  27709

SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency
SMRB, MRDD, AREAL, ORD
Research Triangle Park, NC  27711

ABSTRACT
     A laboratory and field test were performed to select and
evaluate possible replacement sorbents for sampling volatile
organic compounds in stationary sources using SW-846 Method 0030. 
On the basis of laboratory results, Anasorb 747 was selected for
testing in the field using dynamic spiking procedures.  This
modification of the VOST method uses a single tube containing
Anasorb 747 that is preceded by two tubes containing Tenax.  The
modified VOSt method was compared in the field with the VOST method
using traditional adsorbents.  Both the VOST and modified VOST used
a quadruple probe and four similar sampling trains.  Known amounts
of the analytes were introduced into the sampling trains, using the
same certified compressed gas cylinder as a source of test
compounds.  As a general observation, the recovery and precision of
most compounds is improved by using the modified VOST procedure.