Frequent Questions

Is an MDL study required for running Method 310.1 in a certified laboratory? Also, are laboratory blanks (DI water) required to be analyzed in the same frequency as other QC checks (standards, duplicates, spikes)?

Please confirm with your State accrediting authority.

Link to NELAC certification:

For CWA, EPA Method 310.1 which was withdrawn from Table IB at part 136.3 as part of the 2007 MUR (and which is not approved at 141 for DW) is analogous to SM 2320 B (which is approved for both DW and WW). The most recent version of SM 2320 B refers to the QC in Tables SM2020:I and II.

Table I basically says that SM 2320 B is not amenable to an MDL determination and therefore not a required QC element for measurement of alkalinity using the manual titration method. However, table I does indicate that precision and bias should be determined.

Table II shows that calibration or standardization is required as well as analysis of a QCS, a Method Blank (MB), an LFB and analysis of laboratory duplicates. In SM 2020 B, Section 2 "Ongoing Quality Control" Part d "Method Blank (MB)" it states the following: "Include at least one MB daily or with each batch of 20 or fewer samples, whichever is more frequent."

Again, please confirm with your certifying authority.

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