Medical grade silica experiment declaration research and development small test

Medical grade silica experiment declaration research and development of small test silica Eryanghuagui Silicon Dioxide SiO2-χH2O [14464-46-1] This strain reacts sodium silicate with acids (such as hydrochloric acid, sulfuric acid, phosphoric acid, etc.
) or reacts with salts (such as ammonium chloride, ammonium sulfate, ammonium bicarbonate, etc.
) to produce a silicic acid precipitate (ie hydrated silica), which is prepared by washing with water and removing impurities and drying
.

According to the calculation of incandescent products, the content of SiO2 shall not be less than 99.
0%.
【Properties】 This product is a white loose powder
.

This product is dissolved in a hot sodium hydroxide test solution and is insoluble
in water or dilute hydrochloric acid.

【Identification】 Take about 5mg of this product, put it in a platinum crucible, add potassium carbonate 200mg, mix well, blanch at 600 ~ 700 °C for 10 minutes, cool, add water 2ml microthermal dissolved, Slowly add ammonium molybdate test solution (take molybdenum acid 6.
5g, add 14ml of water and concentrated ammonia solution 14.
5ml, shake to dissolve, cool, slowly add the cooled nitric acid 32ml and water 40ml of mixed liquid, let stand for 48 hours, filtered, take filtrate, that is) 2ml, the solution appears dark yellow
.

【Inspection】 Particle size Take 10g of this product, according to the particle size and particle size distribution determination method [General Principle 0982 Second Method (1)] inspection, the amount of test products passing the Seventh Sieve (125μm) should not be less than 85%.
PH Take 1g of this product, add 20ml of water, shake, filter, take the filtrate, determine according to law (general 0631), pH should be 5.
0 ~ 7.
5
.

Chloride Take 0.
5g of this product, add 50ml of water, heat and reflux for 2 hours, let it cool, make up with water to 50ml, shake well, filter it, take 10ml of filtrate, check according to law (general 0801), and compare with the control solution made of standard sodium chloride solution of 10.
0ml, no more concentrated (0.
1%)
.

Sulfate Take 10 ml of the sub-filtrate under chloride, check according to law (general rule 0802), and compare with the control solution made of standard potassium sulfate solution of 5.
0 ml, no more concentrated (0.
5%)
.

Drying weight loss Take this product, dry at 145 ° C for 2 hours, the weight loss shall not exceed 5.
0% (General 0831).
Blazing weight loss Take 1.
0g of the test product left over from the dry weightless item, weigh it precisely, and burn at 1000 °C for 1 hour, and the weight loss shall not exceed 8.
5%
of the weight of the dried product.

Iron salt Take 0.
2g of this product, add 25ml of water, 2ml of hydrochloric acid and 5 drops of nitric acid, boil for 5 minutes, let cool, filter, wash the filter with a small amount of water, combine filtrate with lotion, add ammonium persulfate 50mg, dilute with water to 35ml, check according to law (general 0807), compared with the control solution made of standard iron solution 3.
0ml, no deeper (0.
015%)
.

Heavy metal.
Take 3.
3g of this product, add 40ml of water and 5ml of hydrochloric acid, slowly heat and boil for 15 minutes, let it cool, filter it, put the filtrate in a 100ml measuring bottle, wash the filter with an appropriate amount of water, merge the lotion into the measuring bottle, dilute it with water to the scale, shake well, take 20ml, add 1 drop of phenolphthalein indicator solution, add ammonia test solution to light red, add acetate buffer (pH3.
5) 2ml and water to make an appropriate amount of 25ml, check according to law (general 0821 first method), contain heavy metals shall not exceed 30 parts
per million 。
Arsenic salt Take 20ml of solution under heavy metals, add 5ml of hydrochloric acid, check according to law (General Principle 0822 First Law), should comply with the regulations (0.
0003%)
.

【Content determination】 Take 1g of this product, precise weighing, placed in a platinum crucible that has been blazing to constant weight at 1000 °C, blazing at 1000 °C for 1 hour, take out, let it cool, precisely weigh it, wet the residue with water, add hydrofluoric acid dropwise 10ml, steam dry it in a water bath, let it cool, Continue to add 10ml of hydrofluoric acid and 0.
5ml of sulfuric acid, evaporate on the water bath to nearly dry, move to the electric furnace and slowly heat until the acid vapor is removed, burn to constant weight at 1000 ° C, let cool, precise weighing, the weight lost is the weight
containing SiO2 in the test product.

【Category】 Pharmaceutical excipients, flow aids and suspensions, etc
.

【Storage】 Keep it closed
.