Reference method for dibenzofuran and dibenzo-p-dioxin in defoamers: section 1

Section 1: General Information

• 1.1 Scope and Application
• 1.2 Principle and Theory
• 1.3 Interferences
• 1.4 Sample Storage

1.1 Scope and Application

This method applies to the determination of non-chlorinated dibenzo p-dioxin (DBD) and dibenzofuran (DBF) in defoamers at ng/g levels.

1.2 Principle and Theory

The defoamer is steam-extracted into iso-octane and the extract is cleaned up by column chromatography. The concentrated extract is analyzed by gas chromatography-mass spectrometry (GC-MS) in the selected ion-monitoring (SIM) mode.

1.3 Interferences

Other volatile and semi-volatile organics present in the sample and not removed by the column cleanup step may interfere. Combining a high resolution capillary column and a selective detector, such as a GC-MS operating in SIM mode, is usually sufficient to remove these interferences. Compound identity is confirmed by comparing the ratio of peak areas of the quantitation ion and the confirmation ion in the sample to an authentic standard.

1.4 Sample Storage

No stability data are available for DBD and DBF in defoamers. Defoamers are currently stored at room temperature until analysis. To avoid contamination, glass bottles with foil- or Teflon-lined caps should be used to store defoamers.