Electrochemical sensor for the specific detection of peroxyacetic acid in aqueous solutions using pulse amperometric methods
First Claim
1. A decontamination process comprising:
- (a) circulating a decontaminant solution which includes peroxyacetic acid though a treatment vessel which contains items to be decontaminated;
(b) withdrawing a sample of the decontaminant solution into a chamber to contact a working electrode and a counter electrode;
(c) pulsing a voltage between the working electrode and the counter electrode at a selected voltage relative to a reference electrode, the voltage being selected such that an output current generated is correlated to a concentration of the peroxyacetic acid in the sample and substantially independent of a concentration of at least one other oxidizing species in the sample; and
(d) measuring the current generated.
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Abstract
An electrochemical sensor (A, A′) is specific for the detection of peroxyacetic acid in a solution which also contains hydrogen peroxide. A potential is applied between a reference electrode (120, 120′) and a working electrode (118, 118′). A read voltage (FIG. 7) is selectively pulsed across a counter electrode (122, 122′) and the working electrode. The current flowing between the working electrode and the counter electrode is dependent on the peroxyacetic acid concentration in the solution (FIG. 6). By careful selection of the read voltage, the contribution of hydrogen peroxide to the current flow is virtually negligible. The sensor effectively measures peroxyacetic acid concentrations in the range generally employed in sterilization and disinfection baths (100-3000 ppm.).
56 Citations
34 Claims
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1. A decontamination process comprising:
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(a) circulating a decontaminant solution which includes peroxyacetic acid though a treatment vessel which contains items to be decontaminated;
(b) withdrawing a sample of the decontaminant solution into a chamber to contact a working electrode and a counter electrode;
(c) pulsing a voltage between the working electrode and the counter electrode at a selected voltage relative to a reference electrode, the voltage being selected such that an output current generated is correlated to a concentration of the peroxyacetic acid in the sample and substantially independent of a concentration of at least one other oxidizing species in the sample; and
(d) measuring the current generated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 24)
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12. A method of detecting a first oxidizing species in a solution which also contains a second oxidizing species, the method comprising:
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disposing a working electrode and a counter electrode in the solution to be tested;
pulsing a read voltage in the diffusion limiting range across the working electrode and the counter electrode; and
detecting current flowing between the working electrode and the counter electrode, the read voltage being selected such that the current flowing is substantially dependent on a concentration of the first oxidizing species and substantially independent of a concentration of the second oxidizing species in the solution. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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25. A decontamination apparatus comprising:
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a decontamination vessel which receives items to be decontaminated;
a fluid flow path which circulates a decontaminant in a solution comprising a first oxidizing species to the vessel;
a sensor system fluidly connected with the fluid flow path for specifically detecting the decontaminant in the decontaminant solution, the system comprising;
a chamber which receives a sample of the decontaminant solution from the fluid flow path, a working electrode and a counter electrode disposed within the chamber to contact the sample of decontaminant solution; and
an amperometric controller electrically connected with the working and counter electrodes which;
selectively pulses a preselected read voltage across the working electrode and the counter electrode, and detects an output current flowing in a circuit including the working electrode, the counter electrode and the solution, the read voltage being selected such that the output current is substantially dependent on a concentration of the first oxidizing species and substantially independent of a concentration of at least a second oxidizing species in the solution. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification