見附件 13691497252 侯先生 Decachlorobiphenyl elutes off of the XLB phase in 11.5 minutes, while the target compounds listed in EPA Method 8080 are 80% resolved on both columns. Optimization of the expanded list of compounds found in EPA Method 8081A resulted in 80% resolution of the 32 target compounds (plus the surrogates) on the Rtx-440, with the exception of kepone and endrin aldehyde. The Rtx-XLB phase under the same conditions has two poorly resolved pairs: endrin/2,4-DDT & endosulfan II & kepone. The clear advantage of this column pair is the rapid analysis and low bleed without a sacrifice in resolution. These columns have the same elution order for the EPA 8080 pesticides, which is a disadvantage of this application. Although there are elution order differences for the expanded list and the retention times are different for all of the chlorinated pesticides there is still a need to find a more dissimilar stationary phase as a confirmation column