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9.1 |
Preparation
of the sample
About 200 g of the sample obtained from clause 8.3
shall be ground finely enough to pass through 1.00
mm sieve (or ASTM seive no.10 or BS seive no.16
or Tyler Seive no.12) and then kept in a well-stoppered
glass bottle so as to be used for analysis. |
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9.2 |
Moisture
content
9.2.1 Apparatus
9.2.1.1 A weighing balance having readability
of four significant figures
9.2.1.2 Aluminum dish of 45 mm in diameter
provided with the cover
9.2.1.3 Electric air oven equipped
with thermostat
9.2.1.4 Desiccator containing an efficient
desiccant
9.2.2 Procedure Weigh accurately about 5 g of the
composite sample in a dried aluminum dish of known
weight. Heat the uncovered dish and its lid in an
electric oven at 100 + 2°C for 2 hours. When removed
from the oven, immediately cover the lid. Cool in
a desiccator to room temperature and weigh. Repeat
the above process of an hour heating, cooling and
weighing, until the difference in weight between
two successive weighing is less than one mg.
9.2.3 Calculation
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9.3 |
Crude
protein
9.3.1 Apparatus
9.3.1.1 Nitrogen determination apparatus
9.3.1.2 1 dm3 round bottom flask
9.3.1.3 300 cm3 Kjeldahl, flask
9.3.1.4 500 cm3 Erlenmeyer flask
9.3.1.5 Burette
9.3.1.6 hood
9.3.2 Reagents, solutions and preparations
9.3.2.1 Standard sulphuric acid solution
- 0.05 mole/dm3
9.3.2.2 Concentrated sulphuric acid
- 18 mole/dm3 (specific gravity 1.84)
9.3.2.3 Cupric sulphate
9.3.2.4 Potassium sulphate
9.3.2.5 Sodium hydroxide solution prepared
by dissolving 450g of sodium hydroxide in 1 dm of
distilled water
9.3.2.6 Boric acid solution prepared
by dissolving 4 g of boric acid in 100 Cm3 of distilled
water.
9.3.2.7 Indicator solution prepared
by mixing 1 volume of methyl red in alcohol, 0.1
percent (weight per volume) and 5 volume of bromocresol
green in alcohol, 'J.1 percent (weight per volume)
9.3.2.8 Magnesium oxide
9.3.2.8 Pumice stone or glass beads
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