When converting volume to weight, one needs to find the density which will give a conversion factor. For example, the density of water is 1. So, 30,220 x 1(g/ml) = 30,220g.

however, if you're working with something like salt: density NaCl=2.165(g/ml), so 38,220mL x 2.165(g/ml) =82,746
If you're having trouble finding the density of the substance you're trying to measure: i would suggest a google search.

You need density of this substance. Grams are equal to ml* (g/ml).