Poly(neutral red) based hydrogen peroxide biosensor for chromium determination by inhibition measurements

Abstract

Amperometric hydrogen peroxide enzyme inhibition biosensors based on horseradish peroxidase (HRP) immobilised on electropolymerised neutral red (NR) or directly on the surface of carbon film electrodes (CFE) have been successfully applied to the determination of toxic Cr(III) and Cr(VI). Parameters influencing the performance of the biosensor including the enzyme immobilisation method, the amount of hydrogen peroxide, applied potential and electrolyte pH were optimised. The inhibition of horseradish peroxidase by the chromium species was studied under the optimised conditions. Results from the quantitative analysis of chromium ions are discussed in terms of detection limit, linear range and sensitivity. The HRP kinetic interactions reveal mixed binding of Cr(III) with I50=3.8μM and inhibition binding constant Ki=11.3μM at HRP/PNR/CFE biosensors and uncompetitive binding of Cr(VI) with I50=3.9μM and Ki=0.78μM at HRP/CFE biosensors in the presence of H2O2 substrate. Interferences from other heavy metal ions were studied and the inhibition show very good selectivity towards Cr(III) and Cr(VI).

Ultrasensitive photoelectrochemical determination of chromium(VI) in water samples by ion-imprinted/formate anion-incorporated graphitic carbon nitride nanostructured hybrid

“…Measurements of trace levels of Cr(VI) as well as total chromium level in groundwater have attracted much attention for human health and environmental control. Generally, Cr(VI) is analyzed by atomic absorption spectroscopy, UV-vis spectroscopy, inductively coupled plasma-mass spectrometry, fluorescence, or electrochemical analysis [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. However, these methods often suffer from some issues such as complicated separation/pre-concentration procedures, high cost, time-consuming, or lack of portability.…”

From Electrochemical Biosensors to Biomimetic Sensors Based on Molecularly Imprinted Polymers in Environmental Determination of Heavy Metals

“…Speciation ability of Cr is reported in Attar et al (2014). Even if the biosensor is sensitive to both Cr(III) and Cr(VI), authors claim, probably on the basis of the lower sensitivity for Cr(III) (I 50 = 37 μM) in comparison to Cr(VI) (I 50 = 3.8 μM), selective determination of Cr (VI) and Cr(III) in mixtures.…”

Amperometric Detection of Aqueous Silver Ions by Inhibition of Glucose Oxidase Immobilized on Nitrogen-Doped Carbon Nanotube Electrodes

“…56 Previous heavy metal enzyme inhibition-based biosensors have reported response times, defined as the time required to reach steady-state after introduction of the inhibitor, on the order of several minutes 29,30,57 or longer 58 , but often are unreported 33 . In some cases, especially those with irreversible inhibition, the biosensor is incubated in inhibitor solution for several minutes (often 10 min+) at each step in the calibration curve.…”