Purity >97% by NMR. Activated ester of ruthenium complex for acylation of amino acid side chain amines. This label is perfectly suitable for 1D- or 2D-protein gel staining. A simple pre-electrophoresis procedure provides a sensitivity better than SYPRO Ruby and a similar dynamic range. In contrast to SYPRO Ruby, this staining exhibits a logarithmic dependency on the amount of protein.