[ilikeanimals12334]

I am given 3 concentrations, 390 μg ml−1, 780 μg ml−1 and 1.12 mg ml−1. I have filled in a table as shown in the attachment and the question asks to calc the volume so the final concentration is 100 μg ml−1. Can anyone verify if this is correct? The second part asks if 20 μl of one of the diluted samples were to be loaded into a well of an SDS–PAGE gel, how much protein (μg) would be present? and What volume of the diluted samples would be loaded in order to examine 1.5 μg of cellular protein?

For both these answers I have calculated 0.05 μg ml−1 and 29 μg ml−1 respectively but I feel like these may be wrong or my table is incorrectly filled.

[mjc123]

Table looks correct.

For both these answers I have calculated 0.05 μg ml−1 and 29 μg ml−1 respectively

How did you calculate them? Neither answer should be a value in μg/ml. You want a mass and a volume respectively.

[Vidya]

Table is correct because you used this equation
M1V1(before dilution)=M2V2(after dilution) No need of changing units because its a ratio.Just take care M should have same units on both sides and you will get volume in μL
Second part is also very simple
1mL has 100 μg
Convert mL to μL .
1mL = 1000μL
1000μL = 100 μg
Use this ratio to know how much is there in 20μL for each sample
1000μL = 100 μg
It means 0.1μg is present in 1μL
use this ratio for knowing the volume needed.

[ilikeanimals12334]

Oh I just noticed I used the wrong units, brain fart moment.

[ilikeanimals12334]

For the first answer I did 1 x 20/390 but I got confused interpreting the question, I'm awful at maths. It's probably very simple but I suck.