Fluorescence refers to the emission of light by a substance that has previously absorbed light on a different wavelength. It is one of several components that contribute to photoluminescence.
Light is emitted owing to the molecule undergoing a vibrational relaxation from an electronically excited state, where the electrons are residing in a higher level and need to return to their ground state. In order for this to take place, intrinsic fluorophores will emit a photon (the fluorescence) to transfer the extra energy.
Fluorescence actually has a relatively long history of being used in water sciences to identify different types of organic matter present in the water. Fluorescent organic matter consists of intrinsic fluorophores, which are compounds that fluoresce naturally and do not require any reagent to provoke a reaction. Traditional fluorescence spectroscopy uses a desktop fluorescence spectrophotometer which scans a wide range of both excitation and emission wavelengths to provide a detailed view of fluorescent compounds in the water, also known as an EEM. Over time, different excitation/emission pairs have been identified as relating to different types of organic matter and studies have shown they can then be used as a proxy for that group.
Common peaks are Protein-like fluorescence (Peaks T1, T2 and B, Tryptophan-like and Tyrosine-like respectively) and humic-like fluorescence (Peaks C and A, fulvic and humic acids respectively). The peaks are given ‘like fluorescence’ designations due to the complexities associated with identifying the individual compounds that are actually fluorescing at each peak.
Proteus offers a wide range of fluorometers which can detect a variety of different parameters by targeting specific ex/em pairs which are connected with these parameters. All our fluorometers come with a highly effective central wiper to minimise the likelihood of biofouling, which are built into the multiprobe.
