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Procedures for Detection and Quantitation

WORKING DRAFT FOR DISCUSSION

Draft Pilot Study Purpose and Objectives

Background

The Technical Work Group charged two subgroups (Multi-lab and Single-lab) to explore purposes and objectives that a pilot study design should achieve. With input from the two subgroups, the Technical Work Group identified the following purpose and objective statements for presentation and discussion at the December 8-9 FACDQ meeting. Once a pilot study purpose and objective can be defined, the Technical Work Group can begin drafting a definitive study design for the federal advisory committee's consideration.

Purpose

Collect information about various detection and quantitation procedures that will be helpful to the federal advisory committee in its deliberations of detection and quantitation approaches and uses in Clean Water Act programs.

Objectives

Design a study that answers the following pre- and post-study questions:

  1. Is the procedure clearly written?
  2. Can the data be easily processed in the laboratory?
  3. Was the procedure performed correctly?
    • [Note: the Technical Work Group discussed at length the intent of this question. Members agreed that it was appropriate to have pre- and post-study questions. This question falls into the latter category. It is an attempt to evaluate how the performance of the procedure as written. If there is great variation in the analysis of the performance of the procedure, the Technical Work Group agreed that could be due to variation in interpretation of the written procedure and/or that the procedure was poorly written.]
  4. Does the experimental design unduly influence the outcome of the study? Additional clarifying questions from the Multi-lab Subgroup include:
    • Type of method (censored, uncensored, etc.)
    • Works equally well if analyte recoveries are uniformly low, uniformly high, or highly variable
    • Choice of outlier test (not mandated by procedure?)
    • Number of different concentrations tested
    • Number of replicates per concentration tested
    • Magnitude of concentrations tested
    • Relative relationship between spikes (0.25x, .5x, x, 2x, 4x, etc.)
    • Number of laboratories
    • Number of analysts per study or per laboratory
    • Number of instruments per study or per laboratory
    • Sample preparation
    • Number of different days for which analyses are conducted per laboratory
    • Time span over which analyses are conducted per laboratory (week, month, quarter, year)
    • Number of data points per detection or quantitation limit calculation
  5. Does the procedure achieve its intended purpose?
  6. Does the procedure work for all different types of analytical methods?
  7. Does the procedure work if applied to real world sample matrices? (This may also include a broader question evaluating how the procedure applies to real world matrices.)

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