I got 2 peaks for 10nm(58.8) and 100nm(41.2) in Intensity distribution of DLS results but when I convert them to Volume distribution I am getting only one peak for 10nm particle (with 100% volume) can someone explain to me why it is so
Isn’t this exactly what you would expect? The intensity distribution is proportional to r^6 or volume^2 and the volume distribution to volume (obviously!). There’s a 1000-fold difference in scattering intensity and volume between a 10 and 100 nm particle. So (100*0.412)^3/ (10*0.558) ~ 69935/5.58 ~ 12500 times. So, you’ll not see the larger material in a volume distribution as there's over 12000 times as scattering in the intensity distribution. In number terms the difference is 10^6.
Thus the intensity distribution is really sensitive to tiny amounts of aggregation or agglomeration in a system which is why protein chemists favor this presentation (as do the international standards: ISO13321:1996; ISO22412:2008; ASTM E2490-09(15))
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