I run EPA method 8330 for the analysis of nitroaromatics, nitramines, and nitrate esters on two Agilent 1100s and an Agilent 1200. We use in sequence, either a: guard column and a Dionex Acclaim E2 column 250x4.6mm; or a guard column, Phenomenex Envirosep PP 125X4.6mm and a Restek C-18 250x4.6mm. Right now I can resolve 18 of 19 analytes in our list (8330B list, plus 1,2-DNB as surrogate). I'm running a 53:47 DI:Methanol mix at 30 degrees Celsius for the Dionex setup and 28 degrees Celsius for the Restek setup, and a VWD UV-Vis detector at 214 nm for both.

The problem lies in the analysis time I'm looking at - roughly 90 minutes for every setup, due to a gradient I run at the end of the analysis of 100% methanol for 5 minutes (necessitated by some pretty dirty matrices and a contaminant from our Waters SPE cartridges) and a pretty long time to regain baseline stability (20-30 minutes). Anyone have any ideas to shorten analysis time? Different setup ideas? Mobile phase changes? Any ideas would be helpful, as my boss wants to process more samples, and it doesn't look like I'm getting any more instruments anytime soon.