title: Automated in-chip kinetic-catalytic method for molybdenum determination.
abstract: In this work, the automation of a catalytic spectrophotometric method for the determination of molybdenum is presented. For this purpose, a multisyringe flow injection system was coupled to an integrated microconduit that we have called "chip". Reagents and sample were simultaneously dispensed to the chip where complete mixing, heating, and measurement were carried out. The spectrophotometric method is based on the oxidation of 4-amino-3-hydroxy-naphthalenesulphonic acid (AHNA) by hydrogen peroxide catalyzed by Mo (VI). Absorbance of the reaction product was measured at 465 nm. Two optical fibers were used to conduct the light, one from the source to the chip, and the other from the output of the cell to the spectrophotometer. The detection cell was incorporated in the thermostated zone of the chip. The initial rate method, at controlled temperature, was employed to determine the Mo (VI) concentration. The estimated precision was 3.7%, with the working range of 4.0-40 µg L(-1) of Mo (VI), and the limit of detection of 1.2 µg L(-1) of Mo (VI). The system was successfully applied to water samples and pharmaceutical products with a sampling throughput of 20 injections h(-1).
authors.affiliation: Flow Innovation-Research for Science and Technology Laboratories (FIRST labs.), Thailand; Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand.
authors.forename: Piyawan
authors.initials: P
authors.lastname: Phansi
authors.affiliation: Laboratory of Environmental Analytical Chemistry. University of the Balearic Islands, Carretera Valldemossa km 7.5, E-07122 Palma de Mallorca, Illes Balears, Spain.
authors.forename: Camelia
authors.initials: C
authors.lastname: Henríquez
authors.affiliation: Laboratory of Environmental Analytical Chemistry. University of the Balearic Islands, Carretera Valldemossa km 7.5, E-07122 Palma de Mallorca, Illes Balears, Spain.
authors.forename: Edwin
authors.initials: E
authors.lastname: Palacio
authors.affiliation: Flow Innovation-Research for Science and Technology Laboratories (FIRST labs.), Thailand; Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand.
authors.forename: Duangjai
authors.initials: D
authors.lastname: Nacapricha
authors.affiliation: Laboratory of Environmental Analytical Chemistry. University of the Balearic Islands, Carretera Valldemossa km 7.5, E-07122 Palma de Mallorca, Illes Balears, Spain. Electronic address: victor.cerda@uib.es.
authors.forename: Víctor
authors.initials: V
authors.lastname: Cerdà
mesh_terms: D001331:Automation; D002384:Catalysis; D007700:Kinetics; D056656:Lab-On-A-Chip Devices; D057230:Limit of Detection; D008982:Molybdenum / Q000032:analysis*; D012015:Reference Standards
chemical_list: D008982:Molybdenum
keywords: Automation; Chip; Initial rate method; Integrated microconduit; Kinetic-catalytic; Spectrophotometry