LOD study requirement for new standard

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LOD study requirement for new standard

Postby sreed » Wed Feb 02, 2011 1:19 pm

I work in a small wastewater lab (no outside clients) and I run NOX by SM4500NO3-E. I don't report results below the lowest number on my curve (calibration range) per the method, and therefore not currently required to have an LOD study.

I've read Silkie's "revised standards update" in the 3rd quarter 2010 issue of The Institute Review and my question is: Will I be required to do an LOD study under the new standard? Her first comment states that the exclusion for an LOD is unchanged from the 2003 Standard, yet the language has been proposed for the new Standard about excluding ...tests that do not use a calibration curve.

As mentioned above, I don't report anything outside my calibration range, and therefore use the lowest point for the LOQ. Is this acceptable for the 2009 Standard?
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Re: LOD study requirement for new standard

Postby kchapman1 » Thu Feb 24, 2011 12:12 pm

GOOD Question, and I don't pretend to know the answer. I will have someone on one of the TNI expert committees answer this one. Keith

In general I think you are correct in not having to perform an annual LOD determination, that is UNLESS you are testing drinking water since EPA's DW Cert Manual does require an annual "MDL" determination.

Don't forget that you still have to validate your LOQ (lowest calibration standard) annually. This is in section of Volume 1 of the 2009 Standard.
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Re: LOD study requirement for new standard

Postby pjunio » Fri Feb 25, 2011 12:44 pm

The article that Silky wrote in the Third Quarter newsletter referenced a working draft standard that didn't receive sufficient votes to leave the committee. Even if it had left the committee, those changes wouldn't have become effective for some time.

The current TNI Standard doesn't require that you determine your LOD if you don't report data below your LOQ. Keep in mind that if rule or regulation (such as EPA Method 300.0 or the Drinking Water Manual) require you to determine the LOD, then you must do so.
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