See this website http://www.sigmaaldrich.com/

Dear Zuriah Ismail

You can buy them from the following websites.

1- Amberlite IR-120B (H+ form)

http://www.sigmaaldrich.com/catalog/product/sigma/ir120plus?lang=en®ion=SA

http://www.alfa.com/en/go160w.pgm?srchtyp=msds

2- Dowex 1x2 (OH- form)

http://www.sigmaaldrich.com/analytical-chromatography/analytical-products.html?TablePage=9658617

3- Amberlite CG-50 (NH4+ form)

http://www.dow.com/products/market/nutrition/product-line/amberlite/product/amberlite-cg50-(type-1)/

Best Regards

Thank you Depin and Sibtain

 i also want to buy Amberlite CG-50 (NH4+) form