This idea is something of a classic take on chemistry, and is pretty well executed. Its clear to see you've spent some time thinking about the composition and lighting. Exposure, focus and all technical aspects are pretty much dead on but I think one key thing is lacking and that is interest. There's nothing to hold my personal interest in this, so for me its a little easy as a viewer to 'skim over' it and not study the composition etc which is where the beauty of this picture lies. Some ideas to try might be the use of gels to add an extra dimension of interest to your lighting. Play around and see what colours work well. Blue and yellow are a good combination :) I gave this a 6.