title: Implementation of a new integrated d-lactic acid biosensor in a semiautomatic FIA system for the simultaneous determination of lactic acid enantiomers. Application to the analysis of beer samples.
abstract: An integrated amperometric d-lactic acid biosensor involving a gold film deposited by sputtering on a stainless steel disk electrode where the enzymes D-lactic acid dehydrogenase (DLDH) and diaphorase (DP) as well as the redox mediator tetrathiafulvalene (TTF) are coimmobilized by using a dialysis membrane, is reported in this work. Amperometry in stirred solutions at a detection potential of +0.15 V (vs Ag/AgCl reference electrode) provided a linear calibration plot for D-lactic acid over the 1.0×10(-4) to 3.8×10(-3) g L(-1) concentration range, with a limit of detection of 3.1×10(-5) g L(-1). The usefulness of the biosensor was demonstrated by determining D-lactic acid in beer samples with good results. Additionally, the biosensor was implemented together with a commercial L-lactic amperometric biosensor in a semiautomatic flow-injection analysis (FIA) system able to perform a rapid and simple stereo-specific determination of D- and D-lactic without a previous separation step. The operational characteristics of the biosensors under flow conditions were evaluated and its applicability was demonstrated through the simultaneous determination of both enantiomers in beer samples.
authors.affiliation: Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain; InBea Biosensores S.L. Parque Científico de Madrid, C/ Santiago Grisolía 2, 28760 Tres Cantos, Madrid.
authors.forename: E
authors.initials: E
authors.lastname: Vargas
authors.affiliation: InBea Biosensores S.L. Parque Científico de Madrid, C/ Santiago Grisolía 2, 28760 Tres Cantos, Madrid.
authors.forename: M A
authors.initials: MA
authors.lastname: Ruiz
authors.affiliation: Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Campuzano
authors.affiliation: Escuela Politécnica Superior, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
authors.forename: G
authors.initials: G
authors.lastname: González de Rivera
authors.affiliation: Escuela Politécnica Superior, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: López-Colino
authors.affiliation: Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: A J
authors.initials: AJ
authors.lastname: Reviejo
authors.affiliation: Departamento de Química Analítica, Facultad de CC. Químicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid, Spain. Electronic address: pingarro@quim.ucm.es.
authors.forename: J M
authors.initials: JM
authors.lastname: Pingarrón
mesh_terms: D001331:Automation; D001515:Beer / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods*; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism; D004563:Electrochemistry; D017022:Flow Injection Analysis / Q000379:methods*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D019344:Lactic Acid / Q000032:analysis / Q000737:chemistry*; D057230:Limit of Detection; D013237:Stereoisomerism
chemical_list: D019344:Lactic Acid; D007770:L-Lactate Dehydrogenase; D008058:Dihydrolipoamide Dehydrogenase
keywords: Amperometric detection; Enzymatic biosensors; Lactic acid enantiomers; Semiautomatic FIA system; Simultaneous detection