Standard Practice for Performing Detection and Quantitation Estimation and Data Assessment Utilizing DQCALC Software, based on ASTM Practices D6091 and D6512 of Committee D19 on Water

1.1 This software was developed to automate calculations within three ASTM standards: Practices D2777 (outlier removal section), D6091, and D6512.

1.2 The program calculates detection estimates (DE) and quantitation estimates (QE) for the constant, straight-line, exponential, and hybrid (Rocke-Lorenzato) models of the variation of [inter or intra] laboratory standard deviation (ILSD) with concentration. Calculations are shown in the DE_QE worksheet and results are shown in the DLs&QLs worksheet. Several plots are generated showing how well each model fits the data. The least complex model to fit the data with adequate confidence must be used by the ASTM standards.

Note 1—Modeling techniques automated in this Practice and with this software have been shown to work well with most data sets. Users of this software are cautioned that with some, rare data sets, anomalous results may be obtained, and manual forcing of a different model may be required. It has been noted that for some data sets when an exponential model is selected, there may be a lack of convergence on a result or there may be a convergence on two separate results.

1.3 Users of DQCALC should refer to these Practices for the specifics of the scope and application of the Practices.

1.4 The IDE and IQE Practices are concerned with estimates of limits of detection and limits of quantitation based on inter-laboratory data. DQCALC may also be employed to calculate detection and quantitation estimates based on single laboratory data.

1.5 The DQCALC Software consists of an Excel workbook and associated macros and a user manual in Microsoft Word.