EPA's New MDL Procedure via the Method Update Rule

Off-topic conversations and chit-chat.

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https://www.epa.gov/cwa-methods/procedu ... antitation

Anyone using the newer procedure, especially the requirement of monitoring the blanks to recalculate MDLs on a ongoing basis? We are starting to try to implement it and while is seems to be a more rugged and stringent process it is going to take a lot more data processing I believe.

Just wondering what others are doing to implement this.
The past is there to guide us into the future, not to dwell in.
The idea is the data should be obtainable from LIMS as part of normal operation. It won't be as easy for infrequently run analyses.
I agree, we have some analysis like GRO soil that we maybe run 5 samples per year. Even with the old method of needing to run seven replicates, which our state EPA required to be run on three non consecutive days required us to shut down an instrument for a week just to run the MDL study instead of running other analysis on it. But ongoing will still be a problem as there will be so few data points.

The other thing is our QA guy is wanting the analysts to put the info together, which will be a pain to do as we always have enough other work to get finished on time.

I have put together a spread sheet for doing initial MDL studies including the seven spiked samples and seven blanks with all the proper if/then statements to verify the MDLs, it will just need to be expanded for the ongoing blank study.
The past is there to guide us into the future, not to dwell in.
James_Ball wrote:
The other thing is our QA guy is wanting the analysts to put the info together, which will be a pain to do as we always have enough other work to get finished on time.


Our QA got his "wonderful idea" that our results - even though methods were validated by cGMP or GLP - should pass gauge R&R test requirements, a test devised to measure variability in automotive crankshaft diameters.

Even results from oven solids and pH could not pass gauge R&R requirements, so chromatography procedures utilizing multiple sample preparation steps and then chromatographic assay had zero chance !!! Only after wasting multiple hours by multiple analysts with repeated "failures" did QA back off such requirements.

Funny, the QA Director had worked in QC lab at a large detergent company early in his career, but had zero feel for real R&D Analytical Chemistry.
If you have a low spike with occasional batches then it should be up to your QA person to get the data from LIMS and determine MDLs. For that twice a year analysis, maybe 2 per batch.
Steve Reimer wrote:
If you have a low spike with occasional batches then it should be up to your QA person to get the data from LIMS and determine MDLs. For that twice a year analysis, maybe 2 per batch.


This is what we are looking into now. We have contacted the LIMS provider to see if they can create a QC element that is named MDL or MDLcheck that we can add to periodic QC and query on each year. They mentioned they have already had other requests about the same thing so I think they are working on adding a QC algorithm that would help to calculate them on an ongoing basis automatically, which would be wonderful.
The past is there to guide us into the future, not to dwell in.
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