Method for electrochemical detection
First Claim
1. A method for electrochemical detection of an analyte in a fluid, comprising;
- providing a working electrode with a diameter of about 1 μ
m to 100 μ
m in association with the fluid;
applying a first positive potential pulse to the fluid at the working electrode, at a voltage of less than about 1,000 mV. applying a negative analytical potential pulse to the fluid at the working electrode at a voltage between about 0 mV and −
2,000 mV; and
measuring the current flow through the working electrode during the analytical potential pulse.
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Accused Products
Abstract
A method for electrochemical detection (ECD) is disclosed. The illustrated embodiments are particularly adapted to use in detection of analytes separated by capillary electrophoresis. The method is a voltammetric ECD, including a preparatory positive potential pulse, an optional stabilizing pulse at a negative potential, an analytical pulse at extreme negative potentials (e.g., −300 mV to −1,500 mV), and a positive cleaning potential pulse. The methods have been shown to detect analytes previously considered to be electrochemically inactive using more traditional electrochemical methods. Examples of such analytes include various drugs, antibiotics, and peptides.
32 Citations
32 Claims
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1. A method for electrochemical detection of an analyte in a fluid, comprising;
-
providing a working electrode with a diameter of about 1 μ
m to 100 μ
m in association with the fluid;
applying a first positive potential pulse to the fluid at the working electrode, at a voltage of less than about 1,000 mV. applying a negative analytical potential pulse to the fluid at the working electrode at a voltage between about 0 mV and −
2,000 mV; and
measuring the current flow through the working electrode during the analytical potential pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for electrochemical detection of organic analytes, wherein one detection cycle comprises:
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separating a sample of organic analytes using capillary electrophoresis;
providing the separated analytes in a flowing stream to a surface of a working electrode;
applying at least one positive potential pulse to the analytes at the working electrode for between about 1 ms and 100 ms; and
applying a negative analytical pulse to the working electrode at voltages between about −
300 mV and −
1,500 mV versus an Ag|AgCl electrode, for between about 1 ms to 100 ms; and
measuring current through the working electrode during the negative analytical pulse. - View Dependent Claims (26, 27, 28, 29, 30)
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31. An electrochemical detector, comprising electronic hardware and software controlling voltage applied to a sample fluid, the hardware and software configured to apply a voltage in repeated cycles of pulses where each cycle includes:
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a positive electrode preparation pulse of a first magnitude;
a negative analytical pulse; and
a positive cleaning pulse of a second magnitude greater than the first magnitude. - View Dependent Claims (32)
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Specification