Method 5030B specifies a purge time of 11 minutes when using Method 8260 and 15 minutes for Method 8015. Can we change these purge times, or are they cast in stone?
Yes, the purge times can be changed from those listed in the method. The purge times in Method 5030B (and other sample preparation methods) are recommendations, based on the work performed in developing the original procedures. Under the flexibility inherent in most SW-846 methods, you are free to modify the conditions to meet the objectives of a given analysis. Therefore, if you can demonstrate that other purge times perform well enough for your application, then you are free to use them, provided that you use the same purge time for the calibration associated with the samples. EPA plans to clarify this in the next revision of Method 5030, as it has in other recent methods.
