# Which concentration of BSA is recommended for dynamic light scattering experiments?

What is the recommended concentration of BSA to be mixed with water so as to prepare a very dilute solution in order to clearly study the intensity-intensity correlation with single scattering ?

I want to plot the intensity vs time correlation curve/graph, and eventually calculate the hydrodynamic radius in each case. I've seen different journals and texts provide varied concentrations ranging from 0.001 g/L to 3 g/L.

• Needs more context. What is your goal? What have you tried? What references have you consulted? Commented Jun 2, 2012 at 6:11
• You should be able to find these answers in any methodology text or looking through the literature.
– user560
Commented Jun 2, 2012 at 13:08
• I've edited the question a bit, it would help a lot if you could add more detail. It would help if you added more detail about the method (I guess it's DLS?) and equipment you're using, I'm don't know much about this area, so I can't say if the information here is sufficient to answer your question. Commented Jun 4, 2012 at 14:27
• Yes i'm using DLS. The objective is to find the hydrodynamic radius of the corresponding protein. I'm doing a project on it and require to know the range of concentration to prepare a dilute solution of the protein with water to visualize single light scattering. Hope that might help. Commented Jun 6, 2012 at 3:48

You can easly calculate the absorbance from Beer's Law

A = εlc

Here you can get the values for Extinction coefficient by sequence at http://web.expasy.org/cgi-bin/protparam/protparam1?P02769@25-607@

So for your example 0.001 g/L 3 g/L with this R code, you can get the absorbance values for each concentration.

> PM <- 66432.9 #g/mol
> c <- seq(0.001,3,0.05) #get values from 0.001 to 3, by 0.05 increment
> V <- 1 #liters
> M = c((c/PM)/V)
> #Lambert Beer Law
> e <- 42925
> l <- 1
> A <- c(e*l*M)
> plot(A ~ c, ylab="A (280nm)", xlab="g/l")
> data.frame("conc"=c, M=M, A=A)
conc            M            A
1  0.001 1.505278e-08 0.0006461407
2  0.051 7.676919e-07 0.0329531753
3  0.101 1.520331e-06 0.0652602099
4  0.151 2.272970e-06 0.0975672445
5  0.201 3.025609e-06 0.1298742792
6  0.251 3.778248e-06 0.1621813138
7  0.301 4.530888e-06 0.1944883484
8  0.351 5.283527e-06 0.2267953830
9  0.401 6.036166e-06 0.2591024176
10 0.451 6.788805e-06 0.2914094522
11 0.501 7.541444e-06 0.3237164869
12 0.551 8.294083e-06 0.3560235215
13 0.601 9.046722e-06 0.3883305561
14 0.651 9.799361e-06 0.4206375907
15 0.701 1.055200e-05 0.4529446253
16 0.751 1.130464e-05 0.4852516599
17 0.801 1.205728e-05 0.5175586946
18 0.851 1.280992e-05 0.5498657292
19 0.901 1.356256e-05 0.5821727638
20 0.951 1.431520e-05 0.6144797984
21 1.001 1.506784e-05 0.6467868330
22 1.051 1.582047e-05 0.6790938676
23 1.101 1.657311e-05 0.7114009023
24 1.151 1.732575e-05 0.7437079369
25 1.201 1.807839e-05 0.7760149715
26 1.251 1.883103e-05 0.8083220061
27 1.301 1.958367e-05 0.8406290407
28 1.351 2.033631e-05 0.8729360753
29 1.401 2.108895e-05 0.9052431100
30 1.451 2.184159e-05 0.9375501446
31 1.501 2.259423e-05 0.9698571792
32 1.551 2.334687e-05 1.0021642138
33 1.601 2.409950e-05 1.0344712484
34 1.651 2.485214e-05 1.0667782830
35 1.701 2.560478e-05 1.0990853177
36 1.751 2.635742e-05 1.1313923523
37 1.801 2.711006e-05 1.1636993869
38 1.851 2.786270e-05 1.1960064215
39 1.901 2.861534e-05 1.2283134561
40 1.951 2.936798e-05 1.2606204908
41 2.001 3.012062e-05 1.2929275254
42 2.051 3.087326e-05 1.3252345600
43 2.101 3.162590e-05 1.3575415946
44 2.151 3.237854e-05 1.3898486292
45 2.201 3.313117e-05 1.4221556638
46 2.251 3.388381e-05 1.4544626985
47 2.301 3.463645e-05 1.4867697331
48 2.351 3.538909e-05 1.5190767677
49 2.401 3.614173e-05 1.5513838023
50 2.451 3.689437e-05 1.5836908369
51 2.501 3.764701e-05 1.6159978715
52 2.551 3.839965e-05 1.6483049062
53 2.601 3.915229e-05 1.6806119408
54 2.651 3.990493e-05 1.7129189754
55 2.701 4.065757e-05 1.7452260100
56 2.751 4.141020e-05 1.7775330446
57 2.801 4.216284e-05 1.8098400792
58 2.851 4.291548e-05 1.8421471139
59 2.901 4.366812e-05 1.8744541485
60 2.951 4.442076e-05 1.9067611831


And you can get this plot from 0.001 to 3 g/l for albumine

Now you can choose the desired concentration for the absorbance you wanna work with