Good lighting! I like the use of negative space, and would even crop out more of the right side for more interest. The blue etchings on the test tube distract just a bit.
Very nice capture! There are a few possible interpretations of the image, but science is certainly one of them. You might want to try placing the tube closer to the 1/3 line on the right to give the frame a bit more drama. Probably a 'landscape' orientation would be best here. Very nive though.