| Abstract: | The laser microprobe mass analyzer (LAMMA ) is a new type of analytical instrument. It is a combination of a laser microscope with a time-of-flight (TOF ) mass spectrometer. By focusing an UV pulse laser beam onto the specimen positive and negative atomic and molecular ions are formed which are detected by the TOF mass analyzer. The detection limits reach 10–20 g for some elements in an excited sample volume of 10–13 cm3. With the aim of finding out whether the LAMMA instrument is capable of quantitative measurements on very small biological samples the 23Na+ and 39K+ contents of single mycobacterial cells (M. tuberculosis H 37 Ra) were measured and the results were compared with those obtained from “integral” methods (AAS, NAA , tracer). Furthermore, the influence of different temperatures applied during the washing procedure of the bacteria on the distribution of the Na+/K+ ratio within the cell population was investigated. First attempts to trace isonicotinic acid hydrazide (INH) in bacteria were made by comparison of the LAMMA spectra of INH treated and untreated cells. |
