Estimating the uncertainty of binary test results to assess their compliance with regulatory limits

Abstract A procedure to calculate the uncertainty associated to a binary response, of the type yes/no, originated from an instrumental screening system, is described. Useful equations have been developed based on statistical intervals, and their validation were performed with standard commercial solution. It was applied to a differential pulse anodic stripping voltammetry (DPASV) screening system to analyse tap water, specifically, for determining Pb 2+ and Cd 2+ above the UE legislation limits, 10 and 5 μg/l, respectively. A cut-off value from the responses of the calibration samples is calculated and compared with the responses obtained for unknown samples. From this comparison, we will be able to take a compliance yes/no decision, with an alpha probability of committing a type I error. Another parameter, r screening , is calculated in order to compare different methods for the same screening application.

[1]  Stephen L. R. Ellison.  Using validation data for ISO measurement uncertainty estimationPart 1. Principles of an approach using cause and effect analysis , 1998 .

[2]  G. Scollary,et al.  A statistical overview of standard (IUPAC and ACS) and new procedures for determining the limits of detection and quantification: Application to voltammetric and stripping techniques (Technical Report) , 1997 .

[3]  Johanna Smeyers-Verbeke,et al.  Comparison of alternative measurement methods , 1999 .

[4]  N E Hawass,et al.  Comparing the sensitivities and specificities of two diagnostic procedures performed on the same group of patients. , 1997, The British journal of radiology.

[5]  Wolfhard Wegscheider,et al.  Peer Reviewed: Measurement Uncertainty , 1997 .

[6]  F. Xavier Rius,et al.  Estimating uncertainties of analytical results using information from the validation process , 1999 .

[7]  Stephen L. R. Ellison,et al.  PerspectiveQuantifying uncertainty in qualitative analysis , 1998 .

[8]  A. E. Greenberg,et al.  Standard Methods for the Examination of Water and Wastewater seventh edition , 2013 .

[9]  B L Milman,et al.  Identification of chemical substances by testing and screening of hypotheses I. General , 2000, Fresenius' journal of analytical chemistry.

[10]  Stephen L. R. Ellison,et al.  Uncertainties in qualitative testing and analysis , 2000 .

[11]  F. E. Satterthwaite.  Synthesis of variance , 1941 .

[12]  F. Xavier Rius,et al.  Evaluating uncertainty in routine analysis , 1999 .

[13]  M. A. Kovrizhnych,et al.  Identification of chemical substances by testing and screening of hypotheses II. Determination of impurities in n-hexane and naphthalene , 2000, Fresenius' journal of analytical chemistry.

[14]  Miguel Valcárcel,et al.  Sample screening systems in analytical chemistry , 1999 .

[15]  W. G. de Ruig,et al.  Characterizing and optimizing analytical method quality , 1996 .