Division 7.3.1 F1

United Kingdom

Use of the lower band of the 95 % prediction interval at the decision limit of the confirmatory method:

$Cut-off value = {BEQ}_{DL} - s_{y,x} \times t_{α,f = m - 2} \sqrt{1 ∕ n + 1 ∕ m + {(x_{i} - \bar{x})}^{2} ∕ Q_{xx}}$

with:

BEQ _DL

BEQ corresponding to the decision limit of the confirmatory method, being the maximum level taking into account the expanded measurement uncertainty

s _y,x

residual standard deviation

t _{α,f = m – 2}

student factor (α = 5 %, f = degrees of freedom, single-sided)

total number of calibration points (index j)

number of repetitions on each level

x _i

sample concentration (in TEQ) of calibration point i determined by a confirmatory method

\bar{x}

mean of the concentrations (in TEQ) of all calibration samples

$Q_{xx} = \sum_{j = 1}^{m} {(x_{i} - \bar{x})}^{2}$ square sum parameter, i = index for calibration point i

Annotations

F1: Substituted by Commission Regulation (EU) 2017/771 of 3 May 2017 amending Regulation (EC) No 152/2009 as regards the methods for the determination of the levels of dioxins and polychlorinated biphenyls (Text with EEA relevance).