Determination of the isomeric forms proportion of fluorogenic naphthalene-2,3-dicarboxaldehyde in a binary mixture of water:methanol using electrochemical methods.

The electrochemical response of the fluorogenic label naphthalene-2,3-dicarboxyaldehyde (NDA) in a binary mixture of water/methanol was characterized with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) electrochemical techniques. Naphthalene-2,3-dicarboxyaldehyde does exist in three isomeric forms in aqueous solution: the unhydrated dialdehyde (DA), the acyclic monohydrated (MA) and the cyclic hemiacetal (HAC). The study underlines that the proportion of each of them varies according to the working pH.

Electrochemiluminescence on-a-chip: towards a hand-held electrically powered optofluidic source.

We report a microfluidic platform that integrates several parallel optical sources based on electrochemiluminescence (ECL) of 9,10-diphenylanthracene (DPA) as luminophore agent. The annihilation of DPA radicals provides a low wavelength emission at λ=430 nm in the blue-visible range. By varying the distance between electrodes for each ECL integrated source, this glass/PDMS/glass platform enabled a systematic investigation of the main electrochemical parameters involved in ECL.

Improved electrochemical detection of a transthyretin synthetic peptide in the nanomolar range with a two-electrode system integrated in a glass/PDMS microchip.

An alternative to a three-electrode set-up for electrochemical detection and analysis in microfluidic chips is described here. The design of the electrochemical sensor consists of the surface of the glass substrate covered with a PDMS block which bears the microfluidic channels. A band microelectrode which acts as a working electrode surrounded by a large counter electrode is obtained at the micrometric level to propose a simple and efficient sensing area for on-a-chip analysis.

Investigating the kinetics of paramagnetic-beads linked alkaline phosphatase enzyme through microchannel resistance measurement in dielectric microchip.

Real time monitoring of electrolyte resistance changes during hydrolysis of 4-nitrophenylphosphate (pNPP) by alkaline phosphatase (ALP) bound on paramagnetic-beads was performed into a small dielectric channel. The reaction kinetic fit with a non-competitive substrate-inhibition equation. Michaelis-Menten apparent constant, KM(app), was determined as 0.

Investigating of labelling and detection of transthyretin synthetic peptide derivatized with naphthalene-2,3-dicarboxaldehyde.

Labelling and detection of a synthetic peptide (PN) mimicking a tryptic fragment of interest for the diagnosis of familial amyloidal polyneuropathy have been investigated optically and electrochemically. We decided to covalently label naphtalene-2,3-dicarboxyaldehyde (NDA), a fluorogenic and electroactive molecule on PN. First, the optimization of the labelling chemical reaction was performed by capillary electrophoresis coupled with laser induced fluorescence detection (CE-LIF).