A solid-phase fluorescent biosensor for the determination of phenolic compounds and peroxides in samples with complex matrices

Abstract

A solid-phase fluorescent biosensor for the determination of phenolic compounds (simple substituted phenols and catecholamines) and peroxides has been developed. The biosensor has a simple construction and the analytical signal is measured directly in a biosensitive layer {peroxidase-chitosan} on the sensor surface. This approach allowed analyzing samples with complex matrices (including water-insoluble samples and nontransparent solutions) without their preliminary pretreatment. Two novel fluorescent indicator reactions for the determination of the above-mentioned analytes in wide concentration ranges (from nmol l(-1) to mm l(-1)) which provided an analytical signal registration on a solid phase were proposed. The developed sensor was applied successfully for the analysis of urine, cosmetics, pharmaceuticals preparations, etc.

Tyrosinase Modified Poly(thionine) Electrodeposited Glassy Carbon Electrode for Amperometric Determination of Catechol

“…To compare interfacial properties of bare GCE, pTN/GCE, GA/pTN/GCE and TYR/GA/pTN/GCE surfaces, electrochemical impedance (EIS) was performed by using deoxygenated 0. . The applied potential was set at the formal potential of [Fe(CN) 6 ] 4¹/3¹ redox (i.e., 0.23 V vs. Ag/AgCl at pH 7.0). The frequency ranged from 0.01 Hz to 10 kHz.…”

“…[1][2][3][4] Therefore, the detection of phenolic compounds is of great importance. [5][6][7] Many analytical methods are available for the determination of phenolic compounds based on separation techniques including gas and liquid chromatography, spectrophotometry, and chromatography. [8][9][10][11][12] However, these techniques are complicated not only in sample pretreatment but also in situ monitoring.…”

Determination of the Antioxidant Capacity in Medicinal Plants, Using a Laccase Screen Printed-Type Biosensor

“…The use of Laccase as recognition element during the development of biosensors has led roperties, because when compared with the free enzyme its immobilization usually leads to improved activity and lower value of the apparent Michaelis-Menten constant, Km´, which implies a good immobilization for fabrication of biosensors (1)(2). The latter facilitates performing studies with a wide sort of substrates and the development of new in situ detection systems for chemical processes.…”

In-situ H2O2 generation-on-demand based on ZnO2 nanoparticles for optical sensor systems involving peroxidase

“…[11] The pH range of maximum catalytic activity of peroxidase lies between 5 and 6 [12], whereas HRP activity retained between pH 5 and 10. [13][14][15] Among substrates, there are: aromatic amines [4], phenolic compounds [16], and some other substances [17], including immobilization of HRP in various polymer matrixes for determination of bioactive compounds [8] like hydrogen peroxide and organic peroxides [18], catecholamines and their metabolites [10], phenothiazines [19], protein biomarkers (such as Human IgG (HIgG)) [20] and biocomposites based on PDMS-SiO2NPs with co-localization/co-immobilization of enzyme (HRP or laccase) and substrate (3ethylbenzothiazoline-6-sulfonic acid (ABTS) or 3,3',5,5'teramethylbencidine (TMB)) to create a complete sensor platform or individual sensor elements. [21][22][23] HRP is widely used in laboratory work as an enzyme that catalyzes peroxidation processes, but at the same time it is an equally important analyte in medicine, chemical and pharmacological research, as well as in the biotechnological industry.…”