TITLE
Field Test and Validation of a Source Test Method for Methylene
Diphenyl Diisocyanate

AUTHOR(S)
F. Wilshire and J. Knoll, AREAL/MRDD/SMRB, U.S. Environmental
Protection Agency, RTP, NC 27711 and J. McGaughey and S. Foster,
Radian Corp. RTP, NC  27709

PERFORMING ORGANIZATION NAME AND ADDRESS
Radian Corporation
Research Triangle Park, NC  27709

SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
AREAL/MRDD/SMRB (MD-77A)
Research Triangle Park, NC  27711


ABSTRACT
     Four isocyanates are listed for regulation in the Clean Air
Act Amendments of 1990; hexamethylene-1,6 diisocyanate, methylene
diphenyl diisocyanate, 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 insecticides.

     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 a modified Method 5 sampling train and
stabilized with a derivatizing reagent, 1-(2-pyridyl)piperazine in
toluene.  Derivatized samples are then returned to the laboratory
and analyzed by High Performance Liquid Chromatography with UV
detection (HPLC-UV).  An isocyanate generator was developed in the
laboratory to provide 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 techniques, following the
procedures outlined in EPA Method 301.
     A field test of the isocyanate method, following EPA Method
301 procedures was performed at a pressed board manufacturing
facility.  Results were excellent, with an overall analyte spike
recovery of 92.2 ñ 6.5%.  The method's limit of quantitation (LOQ)
was determined to be 366 ng of MDI/M3.