A Portable Luminometer with a Disposable Electrochemiluminescent Biosensor for Lactate Determination Martínez Olmos, Antonio Ballesta Claver, Julio Palma López, Alberto José Valencia Mirón, María del Carmen Capitán Vallvey, Luis Fermín Portable instrument Microcontroller Electrochemiluminescence measurement Disposable biosensor Lactate determination A hand-held luminometer for measuring electrochemiluminescence (ECL) for lactate determination and based on one-shot biosensors fabricated using screen-printed electrodes is described. The lactate recognition system is based on lactate oxidase and the transduction system consists of electro-oxidation of luminol, with all the reagents immobilized in a Methocel membrane. The membrane composition and reaction conditions have been optimized to obtain adequate sensitivity. The luminometer is based on a large silicon photodiode as detector and includes a programmable potentiostat to initialize the chemical reaction and signal processing circuitry, designed to acquire a low level photocurrent with offset cancelation, low pass filtering for noise attenuation and adjustable gain up to 1012 V/A. The one-shot biosensor responds to lactate rapidly, with an acquisition time of 2.5 min, obtaining a linear dependence from 8 × 10−6 to 2 × 10−4 M, a detection limit of 2.4 × 10−6 M and a sensor-to-sensor reproducibility (relative standard deviation, RSD) of around 7–10 % at the medium level of the range. 2013-10-21T10:59:59Z 2013-10-21T10:59:59Z 2009 journal article Martínez Olmos, A.; et al. A Portable Luminometer with a Disposable Electrochemiluminescent Biosensor for Lactate Determination. Sensors, 9(10): 7694-7710 (2009). [http://hdl.handle.net/10481/28498] 1424-8220 http://hdl.handle.net/10481/28498 10.3390/s91007694 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License MDPI