Andrew Booth's Virtual Protein Purification Laboratory: a great way to learn protein
purification techniques such as 2D gel electrophoresis, size
exclusion chromatography, ion exchange chromatography, affinity
chromatography, heat denaturation and ammonium sulfate fractionation.
Virtual text on UV-Vis spectroscopy (Michigan State University): introduction to UV instruments and basic theory on why molecules absorb where they do.
NIST's
Web book contains thermodynamic data for more than 30,000
organic compounds