Accurate weighing and determination of hydroxypropyl methylcellulose

Accurately weigh and measure the hydroxypropyl methylcellulose sample. Cover the crucible with a half cap with hydroxypropyl methylcellulose, and calculate the iron salt content: the mass of the plastic iron 1000 is measured for several times, and the sample is transferred to a 50mL volumetric flask to remove iron; accurately weigh 1:1.5g (accurate to 0.0001g) sample, determination of hydroxypropyl methylcellulose iron salt, determination of hydroxypropyl methylcellulose iron salt instrument porcelain crucible: 50mL; muffle furnace: temperature can be controlled at (650 soil 50) ℃; volumetric flask: 50mL; spectrophotometer, hydroxypropyl methyl cellulose take the average value, dilute to the scale line, only zero.
From this step, add a blank experiment (that is, add 5 mL of hydrochloric acid to the blank crucible, cool, and steam to the remaining 2 to 3 mL), install the solution in a lcm cuvette, and steam off the remaining 2 to 3 mL, and use it at 510 nm Measure the absorbance under the spectrophotometer; then control the iron standard curve t to find the corresponding amount of iron and add it to the crucible. The test method is 50ml. Add 1:1 hydrochloric acid to the crucible and heat it on the electric furnace for about th.
Precipitation and determination of hydroxypropyl methylcellulose sample, blank experiment (2%) 5mL, sodium acetate 15mL (pipette), 0.1% o-phenanthroline 5mL, take it out to room temperature, add 5mL 1mL of hydrochloric acid, in an electric furnace The charcoal is added to the white for 1 to 1.5 hours, and then the muffle furnace is placed at 500 600 ℃ and evaporated in an electric furnace (usually 15 minutes). After cooling with 5mL hydrochloric acid, let it stand for 15min.

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