Fluorescence is form of spectrochemical analytical method for determining sample molecules based on the on the energy emitted when the an excited analyte at higher energy level moves to lower energy level with accompanying energy emission. The emitted energy is significant since it offers relevant information to facilitate qualitative as well as quantitative analysis. The process starts with absorption of light with appropriate wavelength by a molecule, which moves to the excited state from ground state, and thereby assumes one of the vibrational levels. While in this state, the molecule can stabilize in various was ways such as fluorescence, which is accompanied with light emission. Once absorption takes place, a number of vibrational levels can be occupied. As a result, molecules in higher energy levels stabilize by moving to lowest energy level (vibrational relaxation) from where various processes can restore the molecule to its ground state.
Previous research studies show the extensive use of fluorescence spectrometries and other analytical methods to characterize Ber with DNA [235-241]. For instance, the interaction of berberine and Human serum albumin (HSA) using fluorescence and other methods [242-248] is widely researched. The findings have shown that the binding between the two molecules can quench intrinsic fluorescence produced by single tryptophan as well as cause fluorescence emission from a remnant of another amino acid at 322nm, while berberine–tryptophan complex undergoes fluorescence at 366 nm. These findings can be explained by increased hydrophobic environment in which the tryptophan site is located.
Other studies have reported the application of fluorescence spectrometries, among other spectral techniques, to explore induction of albumin using drug- or other small bioactive molecules [249-250].Baeyens  argues that Fluorescence enhancement of different solutes has widely been over decades with TLC technique. A typical example is the impregnation of TLC silicagel-coated plate with a mixture of berberine and an alkane solution, which is accompanied with enhanced fluorescent signal within the visible region upon irradiation of the system with single wavelength of UV light [252,253].