Document zze6xraM9yGZypLo0YyXLRxRB

Monsanto industrial chemicals co. FROM INAME ft LOCATION* j. P. Mieure - T2F DDAATTEE. -. January 16. 1976 SUBJECT i PCB DETERMINATIONS BY PERCHLORINATION TO D. Wood B2SD CC : W. C. Hammann 0. Hicks R. E. Keller W. B. Papageorge J. C. Weber T3A T2F TIB B2SK B2SK As you requested, we have investigated the products formed from MIPB by the perch!orination procedure used by EPA and ethers to measure and/or confirm PCB's in environmental" materials. We found that MIPB is converted to decachlorobiphenyl. Thus, MIPB and biphenyl interfere with the perchlorination procedure. Many other substituted biphenyls, such as MCS 1839 and various petroleum components, may also interfere. If present in environmental materials, they would cause erroneously high PCB concentrations to be reported. In addition, we have recently obtained a journal article (attached) which points out two other limitations of the perchlorination procedure: 1. High and variable reagent blanks, which cause erroneously high findings. 2. Formation of bromononachlorobiphenyl, which causes low recoveries. We have confirmed that the bromine compound is also formed from MIPB. The above limitations can lead to significant errors in determining trace levels of PCB's in environmental samples. We may want to review these limitations with EPA and others and suggest that they carefully review the validity of the perchlorination technique. Results obtained in the past by this technique may not be valid. ss Attachment J. P. Mieure DSW 297636 STLCOPCB4067549