If I perform BET measurements of the bulk ND powder and calculate the surface area of independent ND particle then, is the estimation of the surface area of the single ND powder by BET is accurate enough to calculate the protein attached to ND particle in aqueous solution?
As the diamond is a rigid material, the surface area can be used in aqueous solution as well.
For the surface coverage of particles by proteins please refer to the following paper:
Article Robust and selective nano cavities for protein separation: A...
By what I understood from your question, you want to know if the BET is reliable for determining surface area for nanodiamonds, right? Yes, it is, if your isotherm allows it! (Need to check for your data, C constant positive, good R², and others parameters that you can find at 2015 IUPAC report for gas adsorption).
Now, if this area can help you finding how much protein is attached to your surface, this I would question. By gas adsorption, you find the amount of gas adsorbed at a monolayer that covers your material (statistical or real monolayer, depending on what theory you use), and knowing the area of the molecule, you can find the area of surface.
That said, unless your protein doesn't interact at all with N2, it won't block active sites, and in your case, nanodiamonds probably won't have pores to be blocked. If your surface area reduces after adsorbing the protein, you have an indication of the protein blocking active sites, but this is not an inquestionable proof.
@Ali Nematollahzadeh Thanks for the reference.
@Luiz Fernando de Sousa Lima Thanks for the explanation. I am not using BET to measure the protein coverage for that I have used other technology, I just want to know the surface area of ND.
So you can use it as long as your isotherm allows you to (and your material is a powder haha)
Luiz Fernando de Sousa Lima , I have experienced problem while measuring SA by BET with HPHT (High pressure high temp) type Nanodiamond, during degassing under vacuum at 150 C temp, the ND powder aggregates.should I reduce temperature ? Do reduced temperature have any effect on SA measurements?
Yes and yes... take in mind that measuring SA with gas adsorption is something similar to using N2 molecules as rule, knowing the amount of N2 that covers your surface and its size, gives you the surface area.
That said, the higher the temperature you use to degass, the more of your impurities adsorbed on the surface will be evaporated, leaving a free surface to be covered by N2.
What equipment are you using for analysis? Autosorb line, by quantachrome, usually have a degass monitor that works fine in those cases, if your sample is passing in the test, you won't have big errors in the measure. If yours doesn't have, I advise you to dry your sample in oven (100 ºC) store it in desiccator until room temperature, weight your sample in cell, and degass it at 100 ºC~120 ºC for 8 hours or even overnight..
Quantachrome (USA) instrument. and degassing work fine, but i faced problem during one of the diamond measurements. HPHT Diamond aggregated while degassing at 150 ºC overnight.
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