TITLE
Development and Validation of a Source Test Method for 2, 4-Toluene
Diisocyanate

AUTHOR(S)
F. Wilshire and J. Knoll, EPA/AREAL/MRDD, RTP, NC 27711 and S.
Foster and J. McGaughey, Radian Corp., RTP, NC

PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Atmospheric Research and Exposure Assessment Laboratory, MRDD/SMRB
Research Triangle Park, NC  27711 

SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency
Atmospheric Research and Exposure Assessment Laboratory, MRDD/SMRB
Research Triangle Park, NC  27711

ABSTRACT
   Four isocyanates are listed for regulation in the Clean Air Act
Amendments of 1990: hexamethylene-1, 6 dissocyanate, methylene
diphenyl diisocyantate, and 2, 4-toluene diisocyanate, each of
which is used in the production of polymers, and methyl isocyanate
which is an intermediate in the manufacture of the insecticide
carbaryl (i.e., SevinR dust).

     To support projected regulations, a study is under way to
produce a source sampling and analysis method for the four
pollutants cited above.  In the procedure under development, the
isocyanates are collected in an absorbing solution and derivatized
with 1-(2-pyridyl) piperazine and analyzed by HPLC with UV
detection.  A system was developed in the laboratory to generate
isocyanate atmospheres for optimization of sampling parameters and
chromatographic conditions.  The accuracy and precision of the
method is determined in the field using train spiking and
multiprobe sampling following the procedures outlined in EPA Method
301.

     A field test of the isocyanate method, following EPA Method
301 procedures was performed at a flexible foam manufacturer in the
Greensboro-High Point, NC area.  Results were excellent, with
analyte spike recoveries of 91% ñ 6%.  The method's limit of
quantitation (LOQ) was determined to be 351 ng of TDI/M3.