0000000000464921

AUTHOR

Gustavo A. Rivas

showing 3 related works from this author

Indicator-free electrochemical DNA hybridization biosensor

1998

A new electrochemical hybridization biosensor protocol without an external indicator is described. The biosensor format involves the immobilization of inosine-substituted (guanine-free) probe onto the carbon paste transducer, and a direct chronopotentiometric detection of the duplex formation by the appearance of the guanine oxidation peak of the target. Such a use of the intrinsic DNA electrochemical response for monitoring hybridization events offers several advantages (over the common use of external indicators), including the appearance of a new peak, a flat background, or simplicity. A 4 min short hybridization period allows a detection limit around 120 ng/ml. Performance characteristi…

Detection limitChromatographyChemistryGuanineDNA–DNA hybridizationAnalytical chemistryElectrochemistryBiochemistryAnalytical ChemistryDna hybridization biosensorchemistry.chemical_compoundTransducerEnvironmental ChemistryMolecular probeBiosensorSpectroscopyAnalytica Chimica Acta
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FIA-Fluorimetric assembly for the determination of noradrenaline hydrochloride by a solid-phase reactor with immobilized hexacyanoferrate(III)

1997

An FIA assembly provided with immobilized hexacyanoferrate(III) is proposed for the fluorimetric determination of noradrenaline hydrochloride. The oxidative reagent is immobilized by means of a strong anion-exchange resin. The FIA manifold is very simple and the calibration graph is linear over the range 0.5–75mgl−1 noradrenaline hydrochloride with an r.s.d of 0.88% (17 replicates) and a sample throughput of 84h−1. Foreign compounds such as NaCl, sucrose, lactose and sodium sulfate caused no significant errors. The procedure is applied to the determination of noradrenaline in a medicinal formulation.

chemistry.chemical_compoundChromatographychemistryHydrochlorideCalibration curveReagentSodium sulfateFluorescence spectrometryQuantitative analysis (chemistry)Dosage formFluorescence spectroscopyAnalytical ChemistryMikrochimica Acta
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Adsorption and Detection of DNA Dendrimers at Carbon Electrodes

1998

Made available in DSpace on 2022-04-28T19:53:27Z (GMT). No. of bitstreams: 0 Previous issue date: 1998-01-01 Dendritic nucleic acids are highly branched and ordered molecular structures, possessing numerous single-stranded oligonucleotide arms, which hold great promise for enhancing the sensitivity of DNA biosensors. This article evaluates the interfacial behavior and redox activity of nucleic acid dendrimers at carbon paste electrodes, in comparison to DNA. Factors influencing the adsorption behavior, including the adsorption potential and time, solution conditions, or dendrimer concentration, are explored. The strong adsorption at the anodically pretreated carbon surface is exploited for …

DendrimersChemistryOligonucleotideGuaninechemistry.chemical_elementDNACarbon pasteCombinatorial chemistryAnalytical ChemistryNucleic acidschemistry.chemical_compoundAdsorptive potentiometryBiosensorsAdsorptionDendrimerElectrochemistryNucleic acidOrganic chemistryBiosensorCarbonDNAElectroanalysis
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