Nutrient analyses - Sand or ash insoluble in hydrochloric acid (derived from ISO 5985)

Principle of sand or ash insoluble in hydrocloric acid analysis

The residue of the ash determination is treated with hydrocloric acid. Minerals are solubilized. The sand is filtered and weighed after incineration.

Procedure of sand or ash insoluble in hydrocloric acid analysis

1. Quantitatively add the residue of the crude ash determination to a 250 ml beaker (high model) and mix with 75 ml 3 mol/L hydrochloric acid. Boil this mixture gently for 15 minutes, using a flat bottom flask containing cold water on top of the beaker, as a cooler.

2. - please wear safety glasses for this filtration step - The hot solution is filtered throuhg a filter paper (S&S 589^5 red band, this filter is acid resistant and contains nos ash) with a diameter of 12.5 cm, fitted into a long-stemmed funnel. Rinse the beaker with hot demineralized water and wash the residue with hot demineralized water until the filter is free of acid (pH paper). Fold the filter and put it back into the same porcelain ash dish. Dry this overnight at 103C, adn the next day, incinerate it in a muffle furnace at 550 C for 2 hours. Place the dish in a desiccator. After 30 second close the cock of the lid

3. After a cooling period of 1 hour, weigh the dish. The weight gain of the dish is the amount of sand in the test portion. The weight of the empty dish is determined in previous procedure.

The difference of the duplicates shall not exceed:

• 3 g/kg (absolute value) for sand contents lower than 30 g/kg

• 10% of the mean value for sand contents from 30-50 g/kg

• 5 g/kg (absolute value) for sand contents from 50-200 g/kg

• 2.5% of the mean value for sand contents from 200-400 g/kg

• 10 g/kg (avoslute value) for sand contents higher than 400 g/kg

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