Program calculate molecular volume

What are the strengths and weaknesses of different MW methods? Disadvantages: Requires accurate sample concentration. Requires accurate absolute calibration. Best when the scattering contrast of the macromolecule is well known.

Best when partial specific volume is well known. The reference standard should have the same scattering contrast as the sample i. The standard and sample should be similar shapes i. Advantages: Accurate for most molecule shapes [5]. More accurate than the volume of correlation method when the signal to noise level of the data is reasonable [5].

Disadvantages: Should struggle when the macromolecule is flexible or extended in solution though [5] found this was not always the case. May need to have the protein density adjusted in some cases default: 0. Sensitive to subtraction errors. More accurate than other methods when there are subtraction errors [5]. Should be accurate for flexible or extended extended macromolecules [3] though [5] found that was not always the case.

Disadvantages: Less accurate than other methods for high signal to noise data [5]. Less accurate than the Porod volume MoW method for extended macromolecules [5]. The integral of qI q needs to have converged see figure below.

Relatively accurate when there are subtraction errors. Disadvantages: Provides no result for flexible systems. Only works for proteins. Disadvantages: Struggles with significant subtraction errors.

DOI: Protein Sci. Read the Docs v: latest Versions latest v2. The other type of properties are independent with molecular size such as density, solubility parameter and refractive index. These properties can not use group contribution method to predict.

But in real, there are many properties estimation schemes for these second type of properties. In that case, we need to know the population of that scheme based. But almost all case, it is not opened. For example, the density case, density is defined as molecular weight divided by molecular volume.

So if we can estimate molecular volume with group contribution method, we can get density very easily. YNU-simulator use functional groups and already determined the factor for molecular volume to each functional groups. I validated the accuracy with database compounds and get result like below.

The population is compounds. Some of the data are not liquid data but solid data. And many melting point data are missing, so I can not find out the density data is solid or liquid.

I need to check carefully to remove such data from parent population. Even though I could not determine all of the factors for functional groups. So I used some software WinMostar to calculate molecular volume and surface area. These theoretical calculation, the molecule is put in vacuum at 0 Kelvin.

In real case, the molecule packing each other and calculated theoretical volume and volume from density is not completely identical. I show the correlation of these relationship. I already showed the usefulness of volume as fixing parameter for predicting critical temperature and critical pressure.

Please refer to that articles. The density decrease as temperature increase. I show the example of acetone. The rightest point is critical density and critical temperature. As you see, around critical point, density is changing dramatically. Hardness Converter and Hardness Calculator. Langelier index calculator. Accuracy water analysis calculation. Ionic strength and activity coeficient. Osmotic pressure calculator. Seawater Reverse Osmosis Cost Analysis. Toggle navigation.

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