IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC ...

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IARC MONOGRAPHS VOLUME 82
Table 1. Melting-points and ultraviolet absorption of aflatoxins
Aflatoxin Melting-point (°C)
Ultraviolet absorption (ethanol)
λ max (nm) ε (L mol –1 cm –1 )
B 1 268–269 (decomposition) 223 25 600
(crystals from chloroform) 265 13 400
362 21 800
B 2 286–289 (decomposition) 265 11 700
(crystals from chloroform-pentane) 363 23 400
G 1 244–246 (decomposition) 243 11 500
(crystals from chloroform-methane) 257 9 900
264 10 000
362 16 100
G 2 237–240 (decomposition) 265 9 700
(crystals from ethyl acetate) 363 21 000
M 1 299 (decomposition) 226 23 100
(crystals from methanol) 265 11 600
357 19 000
From O’Neil et al. (2001)
columns, which are simple and rapid to use, and with reduction in the use of toxic
solvents for extraction and clean-up.
Quality assurance for the analysis of aflatoxins B 1, B 2, G 1, G 2 and M 1 in foods is
available for laboratories through the American Association of Cereal Chemists’ Check
Sample Program and the Analytical Proficiency Testing Programme administered in the
USA and the United Kingdom, respectively.
As contamination may not occur in a homogeneous way throughout a sample of
maize or peanuts 1 , good sampling and sample preparation procedures must be used to
obtain accurate quantitative results. Summaries of the procedures, variability and application
of sampling plans for mycotoxins are included in Section 1.5 and in the European
Commission directive 98/53/CE (European Commission, 1998a).
A number of approaches have been used to analyse aflatoxins and their metabolites
in human tissues and body fluids. These include immunoaffinity purification, immunoassay
(Wild et al., 1987), high-performance liquid chromatography (HPLC) with fluorescence
or ultraviolet detection and synchronous fluorescence spectroscopy (Groopman
& Sabbioni, 1991). Molecular biomarkers, such as urinary markers, metabolites in milk
and parent compounds in blood, are used for determining exposure to aflatoxins
(Groopman, 1993).
1 Maize (corn) and peanuts (groundnuts) will be used throughout this volume for corn and groundnuts.