MEASURING NITROGEN OXIDES AND OTHER GASES BY OZONE FORMATION
First Claim
1. A system, comprising:
- (a) a first radiation source operable to irradiate a gas sample to effect decomposition of a selected first sample component into a second component and oxygen atoms, the oxygen reacting with molecular oxygen in the gas sample to form ozone;
(b) the second component reacting with ozone to cause a decrease in ozone; and
(c) a first detector adapted to detect and/or measure ozone in the gas sample.
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Accused Products
Abstract
A photochemical sensing system enables the measurement of nitrogen oxides (nitrogen dioxide and nitric oxide) by photolyzing nitrogen dioxide to form oxygen atoms which combine with oxygen molecules to form ozone. Ozone reacts with nitric oxide to for nitrogen dioxide-decreasing ozone. Changes in ozone concentration are measured as a surrogate for the nitrogen dioxide and nitric oxide. Any species which photolyzes to yield oxygen atoms may be measured by this technique. Additional specificity for nitrogen oxides is conferred by allowing the nitric oxide to react with the ozone to recreate the nitrogen dioxide. By periodically photolyzing the nitrogen dioxide (to form ozone), and then allowing the resulting nitric oxide to react with the ozone (thereby reducing ozone), a pulsed signal is obtained whose amplitude is proportional to the total amount of nitrogen dioxide and nitric oxide present. Medical applications include measuring nitric oxide concentrations in expired air samples.
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Citations
31 Claims
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1. A system, comprising:
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(a) a first radiation source operable to irradiate a gas sample to effect decomposition of a selected first sample component into a second component and oxygen atoms, the oxygen reacting with molecular oxygen in the gas sample to form ozone; (b) the second component reacting with ozone to cause a decrease in ozone; and (c) a first detector adapted to detect and/or measure ozone in the gas sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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- 10. A system adapted to measure one or more of nitric oxide and nitrogen dioxide in a sample using radiation-induced changes of ozone concentration.
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19. A method, comprising:
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(a) irradiating a sample to convert a selected first sample component into a second component and oxygen atoms, the oxygen reacting with molecular oxygen in the sample to form ozone; (b) the second component reacting with ozone to cause a decrease in ozone; and (c) measuring at least one of a concentration and a change in concentration of ozone, nitric monoxide, and nitric dioxide after step (b). - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method to determine NO in a breath sample from a human, said method comprising:
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(a) exhaling breath sample through a respiratory circuit into a NO analyzer; b) said analyzer capable of measuring photochemically modulated changes of ozone concentration in said sample; c) said changes of ozone concentration converted into concentration of NO in said air ample. - View Dependent Claims (30, 31)
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Specification