| Summary: | 碩士 === 國立東華大學 === 物理學系 === 104 === The sizes of large biomolecules and bioparticles are in the range from 1 nm to 100 m. These large biomolecules and bioparticles include protein complexes, viruses, bacteria and cells. So far the highest mass that a quadrupole time-of-flight mass spectrometer can measure is HK97 capsids with mass of 18 MDa (size ~50 nm) and charge of 350 using the electrospray ion source (ESI)[1]. For sizes greater than 3 m, a charge detection quadrupole ion trap mass spectrometer (CD-QIT MS) can measure the mass and mass distribution of cells with laser induced acoustic desorption (LIAD) ion source[2]. But measurement of the sizes from 50 nm to 3 m is still very challenging for mass spectrometric scientists. Although mass of single bacteria and viruses can be measured with a quadrupole ion trap by light scattering method from sizes 80 nm to several m, but the measuring speed is too slow to be widely used for practical consideration.[3] Here, we propose for the first time a laser-induced plasma (LIP) ion source to enhance the charges of bacteria particles up to few thousands. With LIP ion source, the intact mass of bacteria and their mass distribution can be measured with CD-QIT MS. Several bacteria were measured including Staphylococcus aureus, Escherichia coli and the measured mass and mass distribution is in consistent with their size distribution measured by the optical microscope method. The charge number is enhanced about one order of magnitude as compared to LIAD method
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