6-Carboxyfluorescein (6-FAM) is a widely used fluorescent dye and labeling reagent in molecular biology. It is primarily employed for conjugating to oligonucleotides (e.g., PCR primers, TaqMan probes, molecular beacons), peptides, antibodies, and other biomolecules in applications such as real-time PCR (qPCR), DNA sequencing, genotyping, and FRET-based assays. It also serves as a fluorescent tracer in biological and environmental studies to track fluid flow and transport processes. In cell biology, it acts as a dye for assessing cell viability and membrane integrity. Utilized in fluorescence microscopy to visualize cellular structures and processes, and in assays for enzyme activity and molecular interactions. Its high fluorescence intensity (excitation ~492 nm, emission ~517 nm), photostability, and conjugation efficiency make it ideal for diagnostic kits and research.