Reference method for dibenzofuran and dibenzo-p-dioxin in defoamers: section 2

Section 2: Apparatus and Reagents

• 2.1 Apparatus
• 2.2 Reagents

2.1 Apparatus

The following is a list of apparatus needed to carry out this procedure. Note that all glassware must be washed and dried, using the same procedure as that used for trace organic analysis.

1. Volumetric flasks - 10, 50 and 100 mL.
   
2. Steam distillation heads (see Figure 1 for construction and dimensions).
   
3. Round-bottom flasks - 500 and 250 mL.
   
4. Graduated centrifuge tubes - 15 mL with standard tapered glass stoppers or Teflon-lined screw caps.
   
5. Chromatographic columns - 400 × 10 mm (id) with Teflon stopcocks.
   
6. Three-stage Snyder columns - about 30 cm long.
   
7. Heating mantles with temperature controls.
   
8. Drying oven for glassware.
   
9. Oven for activating alumina at 130°C.
   
10. A GC-MS with good sensitivity operating in selected ion-monitoring mode. As an example, a HP5880A GC interfaced to a HP5970B Mass Selective Detector and a data system were used. Other equally or more sensitive systems may be used.
    
11. Fused silica capillary column - 30 m × 0.25 mm (id) coated with 5% diphenyl, 94% dimethyl, and 1% vinyl polysiloxane phases, 0.25 μm film thickness.
    
12. Hamilton syringes - 10, 50, 100, 250 and 500 μL.

Figure 1: Steam Distillation Head

2.2 Reagents

The following reagents are used in this procedure. Note that all organic solvents must be of distilled-in-glass grade with blanks suitable for residue analysis.

1. Iso-octane.
   
2. Petroleum ether (P.E., b.p. 30 to 60°C).
   
3. Dichloromethane.
   
4. Alumina - basic, 100 to 200 mesh, Brockman Activity 1, activated at 130°C overnight and kept in a tightly sealed bottle placed inside a desiccator until use. Reactivate adsorbent once every two weeks.
   
5. Anhydrous sodium sulphate previously heated at 600°C overnight.
   
6. Reagent water- defined as water in which an interferent is not observed at the method detection limit of the parameters of interest. For example, a sample was used that was prepared by passing distilled water through a 4-cartridge purification unit.
   
7. Dibenzofuran - 99+%.
   
8. Dibenzo-p-dioxin - 98+%.
   
9. Dibenzofuran-d₈ and dibenzo-p-dioxin-d₈ - 99.0 atom % D.*
   
10. Hexamethylbenzene - 99%.
    
11. Boiling chips - anti-bumping granules of fused alumina. Teflon boiling stones can also be used.

* When available, ¹³C-labelled DBF and DBD surrogates can be used instead of the deuterated surrogates.