Best method for the analysis of vitamins and metals in health supplements?

[pizzalover]

I am looking at analysing a range of vitamin supplements in order to quantify both their water soluble vitamin and metal content.

I intend to use LC-MS for the vitamins and FAAS for the metals. Are these the best methods would you say or is there a better method?

Also I am not 100% sure on the sample preparation stage and which solvent to dissolve the tablets in once crushed. Or possibly whether I may require to use microwave digestion.