TITLE
VOST Charcoal Specification Study

AUTHOR(S)
A. Foster and J. Bursey

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

SPONSORING AGENCY NAME AND ADDRESS
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711

ABSTRACT
The volatile organic sampling train, SW846 Method 0030, (VOST) is
currently one of the leading methodology's available for the
sampling and analysis of volatile organic hazardous compounds from
stationary sources at very low levels.  Method 0030 states that the
VOST sampling tube set must consist of a front tube containing
Tenax and a rear tube containing a sequential bed of Tenax and
SKC Lot 104 petroleumbased charcoal "or equivalent."  The method
does not identify a specific equivalent, nor the performance
specifications which would allow specific equivalent, nor the
performance specifications which would allow determination of an
equivalent.  Lot 104 petroleumbased charcoal is no longer
commercially available.  Laboratories are presently using a wide
range of substitutes with varying performance from batch to batch
of charcoal.  To provide performance specifications and identify a
replacement for SKC Lot 104 charcoal, a VOST charcoal specification
study was initiated.  The following carbonbased candidate sorbents
were considered: TenaxGR (a graphitized Tenax); a Petroleumbased
Charcoal; Ambersorb XE340 (hydrophobic carbonized resin bead);
Anasorb 747 (beaded active carbon with very regular pore size);
Carbosieve SIII (carbon molecular sieve); and a Beaded Activated
Charcoal (BAC) with a very regular pore size.

All candidates except Anasorb and BAC were eliminated because of
performance, cost or handling.  The availability of Anasorb 747
proved to be the deciding factor between it and the BAC. 
Performance, cost, ease of handling, and plentiful supply make
Anasorb 747 a good choice for replacement of SKC Lot 104.