[arnyk]

You could test for it in solution by dipping a wooden stick or wire into the solution and then placing the tip into a burner flame.  Of course this only works when there is a single salt in solution, multiple cations would contaminate the colours.

[xiankai]

but since sodium is in aqeuous mode, and the solid form burns with the characteristic yellow flame, are they the same? because seeing that u would evaporate the solution and possibly the sodium cations could be contained in the water vapour.

[arnyk]

I believe the characteristic yellow flame occurs before any Na+ ions "evaporate" with the water.  I've never run into that problem before...can metallic ions evaporate?

[Borek]

Flame test works for Na⁺. However, it is very sensitive (traces of Na⁺ give color) so it can easily give false positives. You should check that you don't get positive signal before adding tested salt to the solution.