Technical Update Detection / Quantitation and PBMS Richard Burrows STL ACIL Mid-Winter Meeting, February 2006

ACIL objectives  Technically reliable detection and quantitation procedures that are:  Reasonably straightforward to perform  Implemented widely through replacement of the MDL and ML procedures at 40CFR Part 136 Appendix B

D/Q FACA  People Lab Group Richard Burrows (STL) Steve Bonde (Batelle) Nan Thomey (Environmental Chemistry Inc) Cary Jackson (Hach Instruments) State Group Bob Avery, Michigan DEQ Timothy Fitzpatrick, Florida DEP Thomas Mugan Wisconsin DNR Dave Akers Colorado DEP Industry Group John Phillips, Ford Larry LaFleur, NCASI Roger Claff, API David Pilar, Exelon Power Environmentalists Richard Rediske, Michael Murray Barry Sulkin

 People Wastewater treatment group David Kimborough Chris Hornback, National Association of Clean Water Agencies James Pletl, Hampton Road Sanitation District Zonetta English, Louisville and Jefferson County Metrepolitan Sewer District

Technical Workgroup Labs Richard Burrows Steve Bonde States Cliff Kirchmer, Washington State Dept of Ecology Tim Fitzpatrick Industry John Phillips Larry LaFleur Treatment plants Jim Pletl Ken Osborn Environmentalists Richard Rediske David Rocke, UC Davis Federal Bill Foreman, USGS Bill Ingersoll, Navy

Multi lab / Multi concentration procedures  IDE / IQE  ASTM Procedures  LCMRL  Drinking Water  Hubaux Vos

Single lab procedures  Detection  ACIL procedure  Consensus group procedure  MDL  Osborn

Single Lab procedures  Quantitation  ML  MRL  Extension of ACIL procedure?

Single lab procedures  Quantitation  MRL 7 replicates at proposed quantitation limit Mean recovery plus 3.96 times RSD must be < 150% Mean recovery minus 3.96 times RSD must be > 50%  ML 3.18 times L C (MDL) For example, if mean recovery = 75%, then RSD must be < 6%

Definitions  L C  The smallest result that can be distinguished from a blank  L D  The smallest true concentration that gives a result greater than L C  L Q  The smallest concentration where a specified degree of uncertainty is met

Distribution of results from true zero concentration LCLC Distribution of true concentration at zero 0

Distribution for true concentration = L C 0 L C or MDL Distribution of true concentration at L C Note that if the true concentration is L C, 50% of the results cannot be distinguished from a blank False negative rate = 50%

Distribution for true concentration = L D 0LCLC Distribution of true concentration at L D LDLD False negative rate for a true concentration at LD is 1% (or 5%)

Controversies  Is L D needed?  In theory, LD is the concentration for which 1% false negatives are observed  It can be statistically predicted, but requires assumptions regarding qualitative identification criteria, constant variance, spike recovery, normal distribution, etc.  We do not use L D now (MDL = L C )

Controversies  Is L D needed?  L D is very difficult to demonstrate, especially for multi analyte methods  A large number of spikes at concentrations very close to L D would be needed

Controversies  Is L D needed?  If L D is not used then we report values between L Q and L C as estimated  If L D is used, we do the same!  What should the non detect value be?  <L Q, L D, <L C, something else?

What is “Quantitative”?  Above low calibration standard?  Multiple of detection limit?  Better than some defined value of precision and accuracy?  Above low standard and demonstrate detection capability?

Low calibration standard  Pros i. Very simple, no additional work ii. In line with some statements from OSW  Cons i. Very weak technically – some analytes can be calibrated at much lower levels than they can be prepared and analyzed, and very large error (100% or more) in the low point of the calibration has minimal effect on the correlation coefficient.  ii. Will be strongly opposed by industry, and probably Office of Water as well

Some multiple of Lc (eg 3.18)  Pros i. Simple ii. Same as the MDL/ML relationship  Cons i. For some censored tests such as GC/MS, may be below the detectable threshold ii. Will be strongly opposed by industry

Level at which some specified degree of precision and accuracy can be demonstrated  Pros i. Strongest technically ii. Will be supported by industry and the drinking water contingent  Cons i. Hardest to implement – who decides what level of precision and accuracy is acceptable, same criteria cannot be used for all analytes.  ii. Requires a lot of low level spikes to develop the statistics

Combo approach  Low calibration standard plus at least 3X L C plus periodic (eg once per quarter) demonstration of capability with a single L Q level spike extracted analyzed on all instruments  Pros i. Compromise approach, hopefully would satisfy the most people. ii. Reasonably strong technically iii. Reasonably easy to implement  Cons i. Probably will still be opposed by industry ii. More complex than options 1 or 2

Extension of ACIL Detection Limit procedure?  Replace spikes used to determine L D with spikes used to determine L Q  Should be ongoing, not one time or every year  Provides a measure of variance at the quantitation limit that can also be used to meet uncertainty requirements  Frequency? Level?

Controversies  What is L C for a “censored” method?  We do not observe results for blanks, so the level below which 99% of blank results fall is meaningless

Current activities  Collection and evaluation of existing data  Uncensored methods, L C A considerable volume of data has been collected, from commercial, state and wastewater treatment plant labs In general initial assessment seems to indicate that the ACIL and Consensus group procedure work well i.e., the number of blanks above the calculated L C is in the region of 1%

Current activities  Collection and evaluation of existing data  L D, L Q and censored methods Much less data available because low level spikes are needed. PT data may help, at least for L Q

Next steps  Design and perform a pilot study  Evaluate procedures for performance and usability  Next meetings, March and June

PBMS

PBMS  New interest at the agency, driven from the highest levels  Office of Water proposes restating their “Streamlining” proposal

Streamlining  Based on demonstrating equivalent or superior performance to a reference method  Determine and compare to reference method MDL Calibration linearity Calibration verification IPR OPR Matrix spike precision and recovery Blanks

Streamlining Tiers  Different requirements for  Tier 1 Single lab, multi matrix  Tier 2 Multi lab, single matrix from one industry type  Tier 3 Nationwide, multi lab, multi matrix

Problems with “Streamlining”  State audition procedures (both NELAC and non-NELAC)  Legal issues  Problems with marketing non-EPA methods  Some limits would be difficult to meet, Eg:  IPR limits X +/- 5.3s  OPR limits X +/- 6s

An alternative  Remove all possible method details from EPA methods  A detailed procedure could still be developed and published (ES&T, Anal. Chem) but would not be in regulation  Control the performance of the analytical technique for the analyte through QC criteria.

Perchlorate example  EPA has developed 5 new methods for perchlorate, all have some prescriptive details and are not consistent with each other.  Total 169 pages – one analyte

PBMS perchlorate method Perchlorate is determined by LC/MS/MS or IC/MS/MS. Mass 83 is used for quantitation and mass 85 for confirmation. In the absence of interferences, single stage mass spectrometry may be used, in which case use mass 99 for quantitation and 101 for confirmation. 18 O labeled perchlorate is used as an internal standard. Aqueous samples may be analyzed directly or following clean up on solid phase columns. Solid samples are extracted using an aqueous leach. Identification of perchlorate requires peaks for the quantitation and qualifier ions to maximize within one scan, and within 0.1 minutes of the labeled perchlorate internal standard. In the absence of project specific quality control requirements the following must be used:

Questions?