ASTM D6512-07
Standard Practice for Interlaboratory Quantitation Estimate

Standard No.

ASTM D6512-07

Release Date

2007

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D6512-07(2014)

Latest

ASTM D6512-07(2014)

Scope

Appropriate application of this practice should result in an IQE achievable by most laboratories properly using the test method studied. That is, most laboratories should be capable of measuring concentrations greater than IQE_{Z %} with RSD = Z % or less. The IQE provides the basis for any prospective use of the test method by qualified laboratories for reliable quantitation of low-level concentrations of the same analyte as the one studied in this practice, and same media (matrix).

The IQE values may be used to compare the quantitation capability of different methods for analysis of the same analyte in the same matrix. The IQE is not an indicator of individual laboratory performance.

The IQE procedure should be used to establish the interlaboratory quantitation capability for any application of a method where interlaboratory quantitation is important to data use. The intent of the IQE is not to set reporting limits.

1.1 This practice establishes a uniform standard for computing the interlaboratory quantitation estimate associated with Z % relative standard deviation (referred to herein as IQE_{Z %}), and provides guidance concerning the appropriate use and application. The calculations involved in this practice can be performed with DQCALC, Microsoft Excel-based software available from ASTM.

1.2 IQE_{Z %} is computed to be the lowest concentration for which a single measurement from a laboratory selected from the population of qualified laboratories represented in an interlaboratory study will have an estimated Z % relative standard deviation (Z % RSD, based on interlaboratory standard deviation), where Z is typically an integer multiple of 10, such as 10, 20, or 30, but Z can be less than 10. The IQE_{10 %} is consistent with the quantitation approaches of Currie (1) and Oppenheimer, et al (2).

1.3 The fundamental assumption of the collaborative study is that the media tested, the concentrations tested, and the protocol followed in the study provide a representative and fair evaluation of the scope and applicability of the test method as written. Properly applied, the IQE procedure ensures that the IQE has the following properties:

1.3.1 Routinely Achievable IQE Value8212;Most laboratories are able to attain the IQE quantitation performance in routine analyses, using a standard measurement system, at reasonable cost. This property is needed for a quantitation limit to be feasible in practical situations. Representative laboratories must be included in the data to calculate the IQE.

1.3.2 Accounting for Routine Sources of Error8212;The IQE should realistically include sources of bias and variation that are common to the measurement process. These sources include, but are not limited to: intrinsic instrument noise, some "typical" amount of carryover error; plus differences in laboratories, analysts, sample preparation, and instruments.

1.3.3 Avoidable Sources of Error Excluded8212;The IQE should realistically exclude avoidable sources of bias and variation; that is, those sources that can reasonably be avoided in routine field measurements. Avoidable sources would include, but are not limited to: modifications to the sample; modifications to the measurement procedure; modifications to the measurement equipment of the validated method, and gross and easily discernible transcription errors, provided there was a way to detect and either correct or eliminate them.

1.4 The IQE applies to measurement methods for which calibration error is minor relative to other sources, such as when the dominant source of variation is one of the following:

1.4.1 Sample Preparation, and calibration standards do not have to go through sample preparation.

1.4.2 Differences in Analysts, and analysts have little opportunity to affect calibration r......

ASTM D6512-07 Referenced Document

• ASTM D2777 Standard Practice for Determination of Precision and Bias of Applicable Methods of Committee D-19 on Water
• ASTM D6091 Standard Practice for 99 %/95 % Interlaboratory Detection Estimate (IDE) for Analytical Methods with Negligible Calibration Error
• ASTM E1763 Standard Guide for Interpretation and Use of Results from Interlaboratory Testing of Chemical Analysis Methods

ASTM D6512-07 history

• 2007 ASTM D6512-07(2014) Standard Practice for Interlaboratory Quantitation Estimate
• 2007 ASTM D6512-07 Standard Practice for Interlaboratory Quantitation Estimate
• 2003 ASTM D6512-03 Standard Practice for Interlaboratory Quantitation Estimate
• 2000 ASTM D6512-00 Standard Practice for Interlaboratory Quantitation Estimate