QXL™ 570 dyes are optimized quenchers for rhodamines (such as TAMRA, sulforhodamine B, ROX) and Cy3 fluorophores. Their absorption spectra perfectly overlap with the fluorescence spectra of TAMRA, sulforhodamine B ROX and Cy3. This characteristic makes QXL™ 570 dyes excellent quenchers for rhodamines (such as TAMRA, sulforhodamine B, ROX) and Cy3 fluorophores. QXL™ 570 C2 amine readily reacts with carbonyl-containing compounds.