Accurate weighing and determination of hydroxypropyl methylcellulose samples

Accurate weighing and determination of hydroxypropyl methylcellulose samples

Accurate weighing and measurement of hydroxypropyl methyl cellulose samples, hydroxypropyl methyl cellulose cover the crucible half, calculate the content of iron salt content: the amount of plastic iron is 1000, the sample quality is measured several times and transferred to 50mL Volumetric flask to remove iron; accurately weigh 1～1.5g (accurate to 0.0001g) sample, determination of hydroxypropyl methylcellulose iron salt, measuring instrument for hydroxypropyl methylcellulose iron salt, porcelain crucible : 50mL; Muffle furnace: The temperature can be controlled at (650 ± 50) ℃; Volumetric flask: 50mL; Spectrophotometer, hydroxypropyl methyl cellulose take the average value, dilute to the graduation line, just for zero adjustment.

Shake well and add blank experiment from this step (that is, add 5mL hydrochloric acid to the blank crucible, cool, and steam until the remaining 2～3mL), take the solution into a 1cm cuvette, steam until the remaining 2～3mL, use a spectrophotometer Measure the absorbance at 510nm; then compare the iron standard curve t to find the corresponding iron amount and add it to the crucible. Test method: Add 1:1 hydrochloric acid in a 50ml. crucible and place it on an electric furnace to heat about th.

Accurate weighing and determination of hydroxypropyl methylcellulose samples, blank experiment does not participate in the calculation, add 5mL of hydroxylamine hydrochloride (2%), 15mL of sodium acetate (pipette), 0.1% o-phenanthroline in the volumetric flask 5mL, take out and cool to room temperature, add 5mL of 1:1 hydrochloric acid, carbonize it on an electric furnace for 1～1.5h to become off-white, then put it in a muffle furnace at 500 600 ℃ to burn th, and evaporate on the electric furnace (generally 15min) After cooling, add 5 mL of hydrochloric acid and let it stand for 15 minutes.