I have no idea what the lower limit is today.  Way below a ppb for sure for most any organic molecule these days.  The biggest problem you have is contamination of equipment resulting in bad data.  When you are working at those levels you better not have macro amounts of the substance of interest anyplace in the lab where you are doing the analysis or you are going to have contamination problems.

Dick,   Thanks.  I was researching this a bit last night and found no good information.( for roundup in particular)   I did find that the research cited in this case was not finding roundup per say,  but a metabolite of roundup,  is that still a valid claim then? 
It seems as of yet that research is not available for viewing.  


Charles

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