[sadishahid]

Can anyone confirm the answer that if we have NiN03 solution (Unknown concentration), mix 2 mL of solution in 250 mL water, then mix 2 mL of that solution in 1000 mL, then after analyzing it we get 2 mg/L concentration of Ni by using Atomic Absorption.
What will its Ni concentration be in % weight/Volume?

I need the answer urgently as me and my supervisor are at odds over this

[sadishahid]

Can anyone confirm the answer that if we have NiN03 solution, mix 2 mL of stock solution in 250 mL water, then mix 2 mL of latter solution in 1000 mL and obtain 2 mg/L concentration of Ni by using Atomic Absorption and we want to convert it into % weight/Volume,what will be the answer?

[Arkcon]

I hope you don't mind, sadishahid:, that I've merged your two similar questions into one posting.  Its helpful to have all the questions on one page.  Please trouble yourself to read the Forum Rules{click}  There are a number of them that you should review.  We generally like to work through a problem, to help out a student, and your case is no different.  You will accomplish nothing with your supervisor, if all you have to say is "some guys online said ..."  So, lets start by seeing what you've calculated.  Warning:  different nations use different definitions for million, so ppm can have different meanings.

[sadishahid]

Im sorry I wasnt aware of the rules, I read them and ill do my best to abide by them.
The method of calculation I used is:

1. Multiplying the value obtained with dilution factor:
2 mg/L * (250/2) * (1000/2) = 125,000 mg/L

2. Next I converted it into g/mL

125,000 mg/L = 125,000/1000,000= 0.125 g/mL

3. Converted it into w/v %
0.125*100= 12.5%

[Hunter2]

I think it is  correct.

You had an analysis of 2 mg/l Ni.  This amount was originally in a volume of 2 ml before dilution.  So it means the concentration of this solution is 1 mg/ml = 1 g/l. Also this amount was in 2 ml.  So you have 500 g/l which gives with a volume of 250 ml 125 g. The concentration is 125 g/l or in percentage 12,5%

[DrCMS]

Warning:  different nations use different definitions for million, so ppm can have different meanings.

No to the best of my knowledge everyone uses the same definition of million as 1000x1000 = 1000000. 
There is a question of the definition of a billion as either a thousand million or a million million.