How to convert 5 ppm H2 gas into micromolar on using 0.1 g of photocatalyst in 20 ml aqueous solution?

I have used 0.1 g of photocatalyst in 20 ml aqueous solution and after irradiation with UV light, I am getting 5 ppm H2 gas. Please let me know how to convert 5 ppm into micromolar per gram or any...

07 July 2018 8,237 2 View