DAPI is a fluorescent, cell-permeable DNA-binding dye preferentially binds to DNA rich in adenine and thymine. DAPI is useful in measuring nuclear DNA content using flow cytometry for sorting isolated chromosomes and is also useful for microscopic detection of nuclei and nuclear DNA in normal and apoptotic cells. DAPI can also be used to detect mycoplasma and in simple retrograde double-labelling procedures for studying axonal branching employing Evans Blue and Primulin. MW: 350.25. Purity ≥98% by HPLC