Portable system for photodiode-based electrochemiluminescence measurement with improved limit of detection

Several techniques to improve the limit of detection CLOD) of analytical systems for electrochemiluminescent (ECL) reactions are presented. This work focuses on ECL measurement based on photodiodes and techniques to improve it, which were implemented and tested in a portable instrument. Three different topologies of ECL measurement systems were compared. One system consisted of a photo-multiplier (PMT) with a photocounting device and a commercial potentiostat. The other two topologies used an ad hoc potentiostat and a photodiode with different conditioning electronics: one with Field Programmable Analog Arrays (FPAA) and the other using conventional analog electronics with a programmable gain amplifier (PGA). The three systems were tested using triethylamine (TEA) as the analyte and tris(2,2'bipyridyl)ruthenium(II) as the transduction chemistry. The detection limit achieved with the system with conventional electronics and PGA was 0.02 mg l(-1), nine times lower than the system with FPAA and 45 times lower than the commercial system with the photomultiplier (PMT). (C) 2015 Elsevier B.V. All rights reserved.