A. Bluthgen et al., ON THE SUITABILITY OF 2,3,4,7,8-PECDF AS PILOT CONGENER OF THE DIOXINFURAN CONTENT IN RAW-MILK, Kieler Milchwirtschaftliche Forschungsberichte, 46(2), 1994, pp. 127-137
To be able to define a compound as typical pilot congener from a conge
ner mixture, as represented by the theoretically possible 21 0 polychl
orinated dibenzodioxins and -furans and the 17 laterally substituted c
ongeners, the compound coming into consideration has to fulfill essent
ial-criteria, e.g. the prominent occurrence in emissions and depositio
ns/immissions, transfer factors within the food chain furnishing proof
of an enrichment with substrate change, high carry-over rates conside
ring foodstuffs originating from animals, further, special analytical
advantages e.g. sensible response of the detection system and a measur
ing technique at reasonable cost. The 2,3,4,7,8-PeCDF seems to fulfil
these requirements to a far extent, because it represents roughly half
of the toxic PCDD/F equivalents in milk fat, shows a carry-over rate
from feedingstuff into milk fat of 25 - 30%, is very highly correlated
with the other congeners of the mixture in the matrix and can be dete
cted with high sensitivity and mass selectively by means of chemical i
onization with negative ion registration in simple GC/MS combinations.
On the other hand, extensive and, to a far extent, coextractive-free
sample preparation is indispensable, so that here almost no advantages
are to be expected compared with the classical high resolution mass s
pectrometry. The main argument for restricting the dioxin-/furan measu
rement in milk fat to the pilot congener is its rather close correlati
on to the other dioxins and furans studied (up to r=0.99) with actuall
y comparable samples. In addition, the expenditure for the final deter
mination is considerably lower from the point of view of technique and
cost, so that at least screening'' for detecting the background conta
mination of PCDD/F in milk fat could be an area of application for thi
s method.