Limit of detection; Limit of quantification; contaminants; Food; Feed
Abstract :
[en] The European Union Reference Laboratory (EURL) for Polycyclic Aromatic
Hydrocarbons (EURL PAH), the EURL for Heavy Metals in Feed and Food (EURL HM),
the EURL for Mycotoxins (EURL Mycotoxins), and EURL for Dioxins and PCBs in Feed
and Food aim to provide with this document guidance to official food control in the EU
on the estimation of the limit of quantification of analytical methods for the
determination of individual substances in the field of contaminants in feed and food.
The document focusses on estimation of the limit of detection (LOD) and/or limit of
quantification (LOQ) of polycyclic aromatic hydrocarbons (PAHs), heavy metals (HM),
mycotoxins, and polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated
dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs).
The concept presented here consists of two major routes: The first route responds to
the requirements for determination of PAHs, HMs and Mycotoxins. The second route
corresponds to PCDD/F and PCB analysis, where results are calculated as sumparameters
and expressed in toxic equivalents (TEQs), converting thereby congener
concentrations together with estimated LOQs using toxic equivalency factor (TEFs)
into TEQs. Due to the nature of this more complex procedure, emphasis is put in the
area of PCDD/F and PCB analysis on the LOQs, while LODs are of minor consequence.
Terminology in this guidance document was adapted to the chemical analysis of
contaminants in feed and food; hence, some of the general terms defined and used in
international standards were replaced by more specific terms applicable to analytical
chemistry. The presented statistical-mathematical approach is based on elements
taken mainly from DIN 32645:2008-11 (DIN 2008) and ISO 11843-2:2000 (ISO 2000).
This document covers only quantitative methods of analysis.
The authors believe that LOD and LOQ values derived from the application of the
presented experimental methodologies converge to a certain degree. Estimation of
LOD/LOQ values based on blank measurements, and from calibration data is
described. Signal-to-noise ratios are applied in the area of PCDD/Fs and PCBs.
Mathematical terms and statistical background are presented as well.
This guide document shall be applied systematically if measurement results are used
for monitoring purposes and exposure modelling. However, authors are aware that
precise knowledge of LOD/LOQ may not be required when assessing compliance with
maximum levels exceeding LOD/LOQ. This guidance document shall be applied if
maximum levels and analysis results are close to the expected LOQ.
The authors acknowledge that the presented approach has its limitations and may not
be generally applicable to all cases.
Disciplines :
Chemistry
Author, co-author :
Wenzl, Thomas
Haedrich, Johannes
Schaechtele, Alexander
Piotr, Robouch
Stroka, Joerg
Eppe, Gauthier ; Université de Liège > Département de chimie (sciences) > Center for Analytical Research and Technology (CART)
Scholl, Georges ; Université de Liège > Département de chimie (sciences) > Center for Analytical Research and Technology (CART)
Language :
English
Title :
Guidance Document on the Estimation of LOD and LOQ for Measurements in the Field of Contaminants in Food and Feed
Publication date :
June 2016
Publisher :
Institute for Reference Materials and Measurements (IRMM), Geel, Belgium