WEF Discussion Forums
Laboratory Management and Technical Issues
Generic Control Limits for RPD and Standards
Are there any EPA guidelines for generic control limits for RPD and control standards? If yes, could you please provide the site?
Generic control limits are pretty much a thing of the past. It used to be, a rule of thumb for inorganics/conventionals was + 20% RPD for precision and 75-125% recovery on spikes.
Now, it's best to get control limits from the individual methods. Compilations exist, but are defined for use in specific context, such as the contract laboratory program.
That being said, there's a nice table called "10.0 Apendix E - Quality Control-Acceptance Criteria" for methods in 40 CFR 136, Table 1. It's in a document titled "Protocol For EPA Approval of Alternate Test Procedures for Organic and Inorganic Analytes in Wastewater and Drinking Water, March 1999, EPA 821-B-98-002."
There may be other compilations, but I couldn't find them quickly in our library. Hope this helps.