Rate of destruction varies depending upon environmental factors, temperature. Fluorescein, for example, is destroyed rapidly in sunlight. Rhodamine WT, however, is adequately stable for field studies. For chlorophyll measurements, samples and standards need to be kept in the dark until read. All flow measurements should employ opaque delivery hoses to minimize photochemical interference.
Limits of detection depend to a large extent on the properties of the sample being measured.
Detectability to parts per billion or even parts per trillion is common for most analytes. Fluorometers achieve 1,000 to 500,000 times better limits of detection as compared to spectrophotometers. Spectrophotometers merely absorb light. Spectrophotometric techniques are prone to interference problems because many materials absorb light, making it difficult to isolate the targeted analyte in a complex matrix. And, if non-target compounds do absorb and emit light, it is rare that they will emit the same wavelength of light as target compounds.