I assume your system is aqueous.  Thus 100 mL of water is 100 g. 1 ng is 10-6 mg or 10-9 g.  there are 10 X 100 mL ( = 100 g water) fractions in 1 L.  That is enough information for you to complete the problem.

I know that things Sir, but I want to know that whether ICPMS gives a result with consideration of weight was taken and volume made or not. I am attaching here 1 of the result

Hi Jitendra

You cannot convert the units, full stop

What you need is to use all the info you have

• Weight of your sample W
• Final volume of your sample (given any sample preparation like acid digestion) V
• concentration given by the icpms C

Final concentration X =(C*W)/V

Just check the units