ASTM D367 Standard Test Method for Xylene-Insoluble Matter in Creosote
5. Apparatus and Materials
5.1 Filtering Crucibles, porcelain with fine-porosity bottom 40-mL capacity, high form, maximum pore diameter, 7µm.
5.2 Filter Apparatus, Filter Flask and Tube, with crucible adapter, and means for producing a vacuum.
5.3 Diatomaceous Silica Analytical Filter, shall be dried to a constant weight at 105°C and stored in tightly stoppered container. (Any other grade of filtering medium should not be used because porosities differ.)
5.4 Balance and Weights, accurate to 0.5 mg.
5.5 Xylene, five-degree distillation range, conforming to Specification D845.
5.6 Acetone, boiling at a pressure of 760 mm Hg within a range of 1.0°C, which shall include the temperature of 56.1°C.
6. Preparation of Filter Crucible
6.1 Make and record all weighings to the nearest 0.5 mg.
6.2 Clean a crucible, if used for less than six determinations as follows. Remove the mat, wash the crucible with distilled water, dry and ignite in a muffle furnace for 1 h at about 800°C. Cool the crucible slowly to prevent cracking and place it in a desiccator while still warm.
6.3 After a crucible has been used for six determinations, remove any residual ash from pores in the filtering area by boiling in 1 + 1 hydrochloric acid. Then boil the crucible in distilled water, thoroughly back wash with distilled water, dry, and ignite as above.
6.4 Transfer 0.45 to 0.55 g of diatomaceous silica to a clean, filtering crucible, distributing it evenly over the bottom. Dry in an oven at 105 to 110°C for 30 min. Cool in a desiccator and weigh. Record the weight of crucible plus diatomaceous silica.
