This common fluorescent reagent often used in carbohydrate analysis, is also useful in fluorescence visualization of lysosomes in live cell lines in culture. This fluorophore that has the unusual environmentally sensitive property of increasing fluorescence in low pH environments. Comparison of staining patterns with the common LysoTracker™ or LysoSensor™ dyes indicated comparable staining, albeit using a higher concentration of NBD-piperazine (1μM versus 100nM for the Lyso-Dyes) but at a lower cost per assay. Also used for the determination of mono- and diisocyantes in air samples, and determination of lactate, hydroxybutyrate and other intermediates in body fluids. The piperazino moiety reacts readily with isocyantes to form the corresponding urea-derivatives. The derivatives can be detected by LC with UV or fluorescent-detection. Spectral data: lambdaex 470nm, lambdaem 540nm.