| 摘要 |
Operation of flame ionisation detectors is carried out with a gas mixture (I) containing 25-50 vol.% oxygen (O2), instead of air. Also claimed is the use of (I) for this purpose. (I) contains 35-45 vol.% O2 and also inert gas(es), especially nitrogen (N2) and/or noble gas(es). In particular, it contains 35-45 vol.% O2 and 65-55 vol.% inert gas, especially N2. In an example, a sample of 5.0 ppm propane in N2 was used to determine the sensitivity of the flame ionisation detector in gas chromatographic separation. With (A) synthetic air (20 vol.% O2, 80 vol.% N2), (B) 25 vol.% O2, 75 vol.% N2, (C) 35 vol.% O2, 65 vol.% N2 and (D) 40 vol.% O2, 60 vol.% N2, the relative sensitivity was (A) 100, (B) 132, (C) 165 and (D) 194.
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