Sorry guys but it is my first time working with RNA.

I have 10 RNA samples (concentrations of 100-200 ng) eluted in 40 TE μl. I am not sure if that is enough to extract enough mRNA downstream applications such as cDNA library? Also, how to work out the "mass" i.e., most kits I reviewed specifiy the input RNA (e.g., PolyATtract ® mRNA Isolation Systems needs 100-1,000µg total RNA) is the "mass" in that manual = concentration X volume ? what if I have less "mass"? wouldn't that kit work? ANy suggestions for kits working with such concentrations?

Thanks!