| 摘要 |
<p>A method for determination of a first electroactive and normally gaseous species (EAGS) and a second EAGS in a fluid medium containing both EAGS; the medium is contacted with a first working electrode (11) that is sensitive but to the first EAGS and generates a first amperometric signal that is indicative of the first EAGS concentration; the medium is also contacted with a second working electrode (21) that is sensitive to both EAGS and produces a second amperometric signal that is indicative of the sum of both EAGS concentrations; the second EAGS concentration is calculated from the difference between the first and the second signal. For example, hydrogen can be measured in the presence of oxygen and this can be applied to monitor a fluid ambient or stream to prevent formation of explosive mixtures or corrosive conditions. The method can be carried out by means of an apparatus comprising two separate membrane-enclosed amperometric cells (1,2) (1, 2) each having a generally conventional structure, or by means of a novel integrated cell structure (4) comprising at least two sensing electrodes (41, 42) and at least one counter electrode (45).</p> |
