188.8.131.52 Preparation. An approximately equal portion of the
shall be separated from each of five (5)
stabilizing rods by means of clean pliers. The portions of coating
shall be broken into 1/8 inch by 1/8 inch pieces, or smaller, and
blended in a beaker. From this blend, about five (5) grams of
coating shall be weighed accurately and placed in the container of
a Waring or similar "blender". About 250 ml of distilled water
shall be added and the coating shall be shredded, and the coated
decanted into a one-liter beaker. Add about 250 ml of distilled
water to the coating which resisted shredding and repeat the
shredding process for three (3) minutes.
184.108.40.206 Extraction. The one-liter beaker containing the shredded
coating shall be placed on a hot plate and boiled for 30 minutes.
The coating solution shall then be filtered through a number 40
Whatman filter paper or equivalent, to collect the shredded coating.
The coating shreds shall be washed-five (5) times with distilled
water, placed in a crucible, and ignited in a muffle furnace at
600C. After the crucible is removed from the muffle furnace and
cooled, the coating ash shall be dissolved in distilled water and
filtered through a number 40 Whatman filter paper; the filtrate
shall be added to the above solution. The solution shall then be
diluted to one liter in a volumetric flash and mixed well. Two
50-ml aliquots of the coating solution shall be taken for analysis.
220.127.116.11 Analysis. A 50-ml aliquot shall be transferred to a 600-
ml beaker, diluted with distilled water to 400 ml, and 2 ml of
concentrated hydrochloric acid shall be added. This solution
shall be heated to boiling and 20 ml of 10% barium chloride solution
added by pipette. The boiling shall be restarted and continued for
five minutes. The sample shall stand overnight and shall then be
filtered through a number 42 Whatman filter paper or equivalent,
and-washed until the filter paper is free of chloride. The filter
paper and precipitate shall then be ignited in a weighed crucible
at 600C to constant weight.
18.104.22.168 Calculation. The percentage of potassium sulfate shall
be calculated by the following equation:
Weight of BaS04 (in grams) x 14.93 x 100
Percent K2S04 = ----,---.,---------,- ----------------------
Weight of Sample (in grams)