UNSUITABILITY OF THE ZEK/AFPS TEST METHOD FOR THE DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS IN CARBON BLACK

Abstract

ABSTRACT The Zentraler Erfahrungsaustauschkreis/Ausschuss für Produktsicherheit (ZEK/AfPS) analytical method established within the Geprüfte Sicherheit (GS) quality label for the determination of 18 polycyclic aromatic hydrocarbons (PAHs) in consumer articles made out of rubber or plastic was demonstrated as unsuitable for carbon black (CB). High molecular weight PAHs are not efficiently extracted from CB through the ZEK/AfPS method when compared with the CB-specific method consisting of 48 h Soxhlet extraction. The low extraction efficiency correlates with the low recovery or loss of the deuterated isotopologues added prior to the 1 h ZEK/AfPS ultrasound extraction of the native PAHs. These phenomena are dependent on the type and concentration level of the various PAHs and are attributed to the relative distribution and adsorption of the native and deuterated PAHs between the CB surface and the toluene phase. These findings are based on comparative extractions of various carbon black grades, use of a larger set of deuterated isotopologues for gas chromatography/mass spectrometry (GC/MS) quantification of native PAHs, and monitoring of the recoveries of the deuterated PAHs added prior to or after the ZEK/AfPS extractions.