please give me some method fo determining Ca and NaCl in food!?

Answer 1

Start with the label.
There is a book called Composition of Foods, put out by the USDA that gives all the foods you would ever want to look up in proportion sizes and also in purchase sizes.
Know your major calcium foods .Milk products.
Avoid canned foods and processed foods to avoid NaCl.
If you use only fresh foods and add no salt to cooking you can avoid NaCl.
Baking soda and powder add sodium .
Softened water adds sodium.
Any processed foods have high sodium.

Answer 2

Try precipitation tests.