Document RJK4NXD9vr2VMqZJd9m5Ov0a

Monsanto 1 T.O.. ,.!, wiT.QHi E. s. Tucker - Technology Department - South Second Street OA'r` *UBJICT July 22, 1970 DETECTION OF POLYCHLORINATED TERPHENYLS (PCT) IN THE ENVIRONMENT CC: W. B. Papageorge - GO E. P. Wheeler - GO M. W. Farrar - Res. 1 R, E. Keller - Res. 1 C. W. Roos - Res. 1 W. R. Richard - General Offices For some time now, we have been concerned about the possibility of PCT being present in environmental samples. So far, we have not detected PCT in any of the environmental samples that we have analyzed for PCB's. ' In conjunction with the above statement, it should be noted that there are several obvious reasons that could explain the con spicuous absence of PCT in PCB containing samples. First, they, may no;t,be present at detectable levels in environmental samples because of the smaller number of pounds presently being manufac tured and consumed or the current end uses may be different enough that they are not released to the environment. Secondly, the difference in physical properties (vapor pressure, water and lipid solubility, environmental stability, etc.) may be responsible for their absence in the environment. Thirdly, their absence could be explained by the limitations of the analytical methods now being used by residue analysts to look for chlorin ated hydrocarbons (CHC). . . We have previously established that. PCT can be extracted and isolated from tissues in the same manner that PCB's are, and . that PCT can be detected by electron capture gas chromatography (EC/GC) if one operates isothermally at high enough temperatures. However, EC/GC is not particularly well suited for the detection of. PCT, especially at the lower temperatures used to analyze for PCB and other CHC. . ' To illustrate this point, I have chromatographed a series of solutions containing a constant amount of Aroclor 1254 (PCB) and increasing amounts of Aroclor 5460 (PCT), The temperature employed is that which we normally use when analyzing for PCB. The EC/GC traces obtained are shown in the accompanying figure. From these chromatograms, it can be seen that the Aroclor 1254 trace is uneffected until the pct/pcb ratio is 10/1 or better. At this point some of the Aroclor 1254 peaks begin increasing and an apparently new peak or two appears. When the ratio is increased to 50/1 the changes become increasingly apparent. A comparison of the EC trace of Aroclor 5460 at the 250 ng level (50/1)- to the trace obtained for Aroclor 1260 shows that the new peaks are really PCB and not PCT. The detection of PCT when analyzing tissues for PCB would, theref6re, require that the ratio of FCt/PCB be something greater than 250/1. We are currently exploring other analytical methods for the detection of PCT. J' E. S. Tucker ih..o.ev ., .db DSW 152549 STLCOPCB4039897 STLCOPCB4039898