Need Tips and Tricks on plate-reading Lycopene production of E.coli

[koitk]

I need to measure the Lycopene production of E.coli strain on different mediums.

I have used Acetone, to extract Lycopene from bacteria, as described in literature. But when I started to measure the absorbance (470 nm) using 96-well microplates, some of the acetone would evaporate and ruin my results (even with the lid on). 

Most of the literature that i have read uses HPLC to evaluate production, but some have used absorbance as well, but they dont specify their methods in great detail.

Can anyone help me by give me some tips, how could i slow down the evaporation. Or maybe i should use a different solvent?

 

Thank you in advance,

a desperate undergrad :)