i have a powder sample of very small quantity around 40-50 mg, and i need to determine the density of this powder. can i mix this with another powder of known density like mannitol/lactose in known quantities and then determine the density differences between pure mannitol/lactose and mixture
you can use a pycnometer and rule of mixture (ROM) to find the density of the said powder. The pycnometer will give you the total density and volume of the mixed powder. From there, you just need to do a simple calculation to measure the powder,
Total density = [mass(powd1) + mass(powd2)] / [volume(pow1) + volume(powd2)]
Yes you can do it as Azmi Kamardin wrote but the result may be saddled with mistake.
Why dont you try to use gas pycnometry or mercury porosimeter though mercury porosimeter is seldom used solely for the determination of envelope, bulk, and skeletal
volume determination of powdered sample.
Best regards.
Pawel
Tahnks Azmi, Murzyn and Nidal.
I do not have a mercusry porosimeter here, however, i can access the gas pycnometer. But, the pycnoiometer needs atleaset 1gm of sample to analyse.
Sasi Yarragudi
The mass is not that important but your sample must occupy at least 20% of the volume of the sample holder for the result to be accurate. My suggestion is to perform the 1st measurement on the excess powder. Then add in your limited powder into the excess one, and perform the measurement again.
I would like to recommend for you to double the gas purging cycles to get a good result. Best of luck.
I will try the method Azmi. many thanks. i was looking for some literature around this so that i can use it as reference but failed to identify one.
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