Liquid cheromatography/mass spectrometry apparatus
A liquid chromatography/mass spectrometry apparatus combines a chromatograph having a liquid delivery part for delivering mixed multiple solvents, and a mass spectrometer having an ionization part for spraying and ionizing. The apparatus has a storing part for storing a relationship between a mixture ratio of the multiple solvents in the liquid delivery part and an optimal or nearly optimal voltage applied to the ionization part, a ratio information acquiring part for computing the mixture ratio over time, a voltage value computing part for computing the optimal or nearly optimal applied voltage at any point, and a voltage controlling part for changing the voltage applied to the ionization part over time. By virtue of the ability to adjust the applied voltage during analysis, the ionization efficiency is always high, and the analysis can be performed with high sensitivity for all of the multiple components in the liquid sample.
1. A liquid chromatography/mass spectrometry apparatus, which combines a liquid chromatograph having a liquid delivery part for performing gradient delivery with mixed multiple solvents, and a mass spectrometry device having an ionization part for spraying and ionizing in a roughly atmospheric-pressure atmosphere a liquid sample separated into components by said liquid chromatograph, said apparatus comprising:
storing means for storing a corresponding relationship between a mixture ratio of said multiple solvents in said liquid delivery part and a substantially optimal voltage applied to said ionization part;
ratio information acquiring means for computing said mixture ratio of multiple solvents in said liquid delivery part over passage of time during analysis of said sample;
voltage value computing means for computing said substantially optimal voltage at any point in time during said analysis based on said mixture ratio obtained by said ratio information acquiring means while referring to information stored in said storing means; and
voltage controlling means for changing said voltage applied to said ionization part over the passage of time in accordance with a computed result from said voltage value computing means.
2. A liquid chromatography/mass spectrometry apparatus according to claim 1 , further comprising information creating means for performing said sample analysis by setting said voltage applied to said ionization part in multiple stages when said mixture ratio of multiple solvents is set to a certain state, so as to determine said substantially optimal voltage at said mixture ratio, and to set said mixture ratio in multiple stages so as to obtain an optimal voltage for each stage, and by using said voltages and mixture ratios to create information for storage in said information storing means.
3. A liquid chromatography/mass spectrometry apparatus according to claim 1 , wherein said ionization part performs nano-electro-spray ionization, and said voltage is applied to a tip of a nozzle for spraying droplets of said liquid sample.
4. A liquid chromatography/mass spectrometry apparatus according to claim 1 , wherein said ionization part performs electro-spray ionization, and said voltage is applied to a body of a nozzle for spraying droplets of said liquid sample.
5. A liquid chromatography/mass spectrometry apparatus according to claim 1 , wherein said ionization part performs atmospheric-pressure chemical ionization, and said voltage is applied to a discharge electrode for ionizing solvent gas molecules.
6. A liquid chromatography/mass spectrometry apparatus according to claim 1 , wherein said substantially optimal voltage is a voltage at which ionization efficiency in said ionization part becomes optimal for a particular mixture ratio.
7. A liquid chromatography/mass spectrometry apparatus according to claim 1 , wherein said voltage controlling means successively changes said optimal voltage each time said mixture ratio changes over the passage of time.
8. A liquid chromatography/mass spectrometry apparatus according to claim 1 , wherein said ratio information acquiring means for computing said mixture ratio comprises accounting for types of said multiple solvents.
9. A liquid chromatography/mass spectrometry apparatus according to claim 1 , wherein said ratio information acquiring means for computing said mixture ratio comprises accounting for flow rates of said multiple solvents.