| 摘要 |
A mass spectrometer comprises first and second chromatography 7,11, preferably gas chromatography, separation means and a mass analyser, wherein in one mode of operation output from the first chromatography means is transmitted to the mass analyser 16, and in a second mode, output from the second means is transmitted. Preferably the chromatography columns are of different lengths to allow sulphur dioxide to elute before carbon dioxide and nitrogen. Also disclosed is an elemental analyser and mass spectrometer, preferably an isotopic ratio mass spectrometer having modes of operation as above; an elemental analyser for combusting a sample, having chromatography columns of different length; an isotopic ratio mass spectrometer for determining carbon, sulphur, and nitrogen; and methods of mass spectrometry and isotopically analysing a sample using two gas chromatography means and a mass spectrometer. |
