Chromatography of amino acids and short peptides. New advances

In Vivo Detection of Glutamate in Tomatoes by an Enzyme-Based Electrochemical Biosensor

The in vivo and on-site detection of key physiology parameters in plants will be of great relevance for precision agriculture and food technology. In this work, a sensitive enzymatic glutamate sensor was successfully developed. To enhance the conductivity and catalytic ability and to fix the glutamate oxidase, Au-Pt nanoparticles were first deposited on screen-printed electrodes, and then carboxylated graphene oxide and carboxylated multiwalled carbon nanotubes were fabricated for the synthesis of the electrode. The detection range of the glutamate sensor is widest (2 μM to 16 mM) up to date, and its detection limit is relatively low (0.14 μM). A number of standard curves were built in the pH range of 3.5-7.5, which can be applied in various plants and fruits. Using this sensor, the glutamate level in tomatoes was determined in vivo. This glutamate sensor has important practical value in precision agriculture. Our strategy also provides a way to establish the detection modes for other biomolecules in plants.

A quinoline-based probe for effective and selective sensing of aspartic acid in aqueous medium: in vitro and in vivo live cell imaging

A highly sensitive and selective “on–off–on” chemosensor for aspartic acid in aqueous solution was established. In vitro live cell imaging against MCF 7 cells and in vivo imaging using C. elegans were successfully demonstrated.

Quantitative analysis of drugs in biological matrices by HPLC hyphenated to fluorescence detection

An overview of the state-of-the art in HPLC coupled with fluorescence detection is presented. Over the last 20 years, the increasing number of methodological papers on this topic (4082 between 1994 and 2004 and 7725 between 2004 and 2014) is testament to its utility in bioanalytical applications. Compared with conventional UV absorbance detection used in HPLC, fluorescence detection can greatly enhance the sensitivity leading to limits of detection similar to those obtained with mass spectrometry, offering researchers a sensitive, robust and relatively inexpensive instrumental method. This work will focus on the analysis of pharmaceutical compounds in different biological matrices, either naturally fluorescent or derivatized with a fluorescent agent, and some of them chiral. Therapeutic applications, sample preparation and derivatization, sensitivity for each example are described.

Glucosamine modified near-infrared cyanine as a sensitive colorimetric fluorescent chemosensor for aspartic and glutamic acid and its applications

A near-infrared colorimetric fluorescent chemosensor has been developed and successfully applied to Glu and Asp imaging in living cells.