Coated electrode, electrochemical sensor and method for detection of hydrogen peroxide
View Patent ↗An electrochemical method for detecting hydrogen peroxide includes providing an electrochemical sensor comprising: a container holding an electrolyte; a coated electrode positioned in the container; and a counter electrode spaced apart from the coated electrode in the container, where the coated electrode includes a conductive substrate and a coating comprising a topological insulator on the conductive substrate. A voltage is applied to the coated electrode and the counter electrode, and a biological specimen is added to the electrolyte to form an analyte solution. Current density is measured. An increase in the current density upon forming the analyte solution indicates presence of hydrogen peroxide in the biological specimen.
1 . An electrochemical method for detecting hydrogen peroxide, the method comprising:
providing an electrochemical sensor comprising:
a container holding an electrolyte;
a coated electrode positioned in the container, the coated electrode comprising: a conductive substrate; and a coating comprising flakes dispersed over the conductive substrate, the flakes having a lateral dimension larger than a thickness thereof and comprising a topological insulator comprising a bismuth and/or antimony chalcogenide having a chemical formula of Bi 2 Se 3 , Bi 2 Te 3 , Sb 2 Te 3 , Sb 2 Se 3 , Bi 2-x Sb x Te 3 , or Bi 2-x Sb x Se 3 , wherein 0<x<2 and the flakes comprise exposed facets having different crystalline domains and/or surface roughness; and
a counter electrode spaced apart from the coated electrode in the container,
applying a voltage to the coated electrode and the counter electrode;
adding a biological specimen to the electrolyte to form an analyte solution; and
measuring current density, wherein an increase in the current density upon forming the analyte solution indicates presence of hydrogen peroxide in the biological specimen,
wherein the electrochemical sensor has a limit of detection of 0.02 μM or less of the hydrogen peroxide.
2 . The electrochemical method of claim 1 , wherein the increase in the current density occurs due to reduction of the hydrogen peroxide catalyzed by the topological insulator.
3 . The electrochemical method of claim 1 , wherein, for the analyte solution including hydrogen peroxide at a concentration of about 0.1 μM or greater, the increase in the current density is at least 2.5 μA/cm 2 .
4 . The electrochemical method of claim 1 , wherein the increase in the current density occurs within about 5 s of adding the biological specimen to the electrolyte.
5 . The electrochemical method of claim 1 , wherein the biological specimen comprises a blood sample.
6 . The electrochemical method of claim 1 , wherein no more than two droplets of the biological specimen are added to the electrolyte.
7 . The electrochemical method of claim 1 , wherein the electrolyte comprises an aqueous solution.
8 . The electrochemical method of claim 1 , wherein the coating does not include a precious metal or an enzyme.
9 . The electrochemical method of claim 1 , wherein the topological insulator is crystalline.
10 . The electrochemical method of claim 1 , wherein surface coverage of the flakes is at least about 8% of the conductive substrate.
11 . The electrochemical method of claim 1 , wherein the coating includes no more than three layers of the flakes.
12 . The electrochemical method of claim 1 , wherein a loading level of the topological insulator on the conductive substrate is in a range from 0.005 mg/cm 2 to 1 mg/cm 2 .
13 . The electrochemical method of claim 1 , wherein, for the analyte solution including hydrogen peroxide at a concentration in a range from 0.016 μM to 65 μM, a sensitivity of the measurement of current density is in a range from about 2500 μA/mM cm 2 to 4905 μA/mM cm 2 .
14 . An electrochemical method for detecting hydrogen peroxide, the method comprising:
providing an electrochemical sensor comprising:
a container holding an electrolyte;
a coated electrode positioned in the container, the coated electrode comprising: a conductive substrate; and a coating comprising flakes dispersed over the conductive substrate, the flakes having a lateral dimension larger than a thickness thereof and comprising a topological insulator comprising a bismuth and/or antimony chalcogenide having a chemical formula of Bi 2 Se 3 , Bi 2 Te 3 , Sb 2 Te 3 , Sb 2 Se 3 , Bi 2-x Sb x Te 3 , or Bi 2-x Sb x Se 3 , wherein 0<x<2 and the flakes comprise exposed facets having different crystalline domains and/or surface roughness; and
a counter electrode spaced apart from the coated electrode in the container,
applying a voltage to the coated electrode and the counter electrode;
adding a biological specimen to the electrolyte to form an analyte solution; and
measuring current density, wherein an increase in the current density upon forming the analyte solution indicates presence of hydrogen peroxide in the biological specimen,
wherein, for the analyte solution including hydrogen peroxide at a concentration in a range from 0.02 μM to 65 μM, a sensitivity of the measurement of current density is in a range from about 2500 μA/mM cm 2 to 4905 μA/mM cm 2 .