Search

Highlights • Deep UV fluorescence is used to discriminate cyanobacteria and microalgae. • Tryptophan and other pigments of planktonic species autofluoresce at 270 nm. • Relative fluorescence peak amplitude are exploited for discrimination. • The proposed method offers easy and direct interpretation of the results. Abstract The deep ultraviolet fluorescence characteristics of several cyanobacteria and microalgae are analyzed and exploited for their discrimination in liquid samples. The proposed approach is based on relative fluorescence peak amplitude of natural pigments in cyanobacteria or other planktonic species commonly present in water bodies. The experimental results demonstrate a clear discrimination between the various species of cyanobacteria and other planktonic species. This approach can be simply implemented in fluorescence measurement systems for real-time detection of cyanobacteria, provided that they are able to operate in deep ultraviolet. [ABSTRACT FROM AUTHOR]

Abstract Filtering strategies are a crucial aspect for signal detection in many fluorescence based systems such as chemical and/or biochemical sensors. Here we present the design, fabrication and characterization of a new waveguide absorption filter capable of maximizing the fluorescence signal collection thanks to its high numerical aperture. The comparison in terms of performance with an interference filter demonstrates how this new type of absorption filter still works well even when the fluorescence light forms large incidence angles with the perpendicular at the filter input face, a condition for which any other filtering strategy fails. Finally, as a proof of concept, a preliminary fluorescence measurement carried out on an IgG - anti IgG bioassay shows the potentiality of our absorbing waveguide filter in comparison to that of the interference one. The use of such filtering strategy can improve and simplify the fluorescence signal detection in several fields of sensing application, from Point of Care Testing to environmental monitoring. [ABSTRACT FROM AUTHOR]