Yes that is a suitable equation for preparing working solutions. You probably can use serial dilutions but for GC and HPLC you are not usually calibrating over several orders of magnitude so it is less relevant.

I think C1V1=C2V2 comes to bare even in serial dilutions

But with serial dilution when your first standard is wrong or has an error perhaps the concentration is miscalculated it is going to run through the subsequent ones you are preparing

You usually begining  from  a commercial solution (commercial bottle where you have density and% weight)

So you are obliged to make a dilution taking into account the equation CiVi = CfVf

Ci initial concentration, Vi initial volume and Cf final concentration Vf final volume.

From the density and the% mass, you have the initial concentration

You can prepare your solutions in volumetric flasks of 50ml or 100ml without problem

Thank you every one

For sure. It represents the mass conservation law. Have a great day