508 Pesticide recovery issues???

[jss37992]

Hello everybody. I posted a topic a while back about endrin breakdown issues. I have snipped that problem in the butt, however it now seems I cannot get my recovery of my target analytes above 50 percent. The only deviation from the method is my extraction technique. I am using continuous liquid-liquid extractors rather than sep. funnels. The strange thing is when I run for PCB's only, my recoveries are near 100 percent using the liquid-liquids. What could cause my recovery loss. I am still fairly new to GC and am still in some what of a learning process.

[8jw8]

I'm not sure about continuous liquid-liquid extraction as we always used sep funnels but I know PCBs are pretty much not going anywhere. Pesticides seem to be a bit more volatile

[Bigbear]

A quick check would be to extract a standard using a sep funnel. hat would confirm or exclude any question about your continuous extraction.