The construction of a practical UV microhyphen;Raman spectrograph capable of selective excitation of bacterial cells and other microscopic samples has been described. A reflective objective is used to focus cw laser light on a sample and at the same time collect the scattered light at 180deg;. With the aid of a quartz lens the image produced is focused on the slits of a spectrograph equipped with a single 2400 grooves/mm grating optimized for 250 nm. Spectra were detected by means of a bluehyphen;intensified diode array detector. Resonance Raman spectra ofBacillussubtilisandFlavobacteriumcapsulatumexcited by the 257.2 nm output of a cw laser were recorded in the 900ndash;1800 cmminus;1region. Bacterial cells were immobilized on a quartz plate by means of polylysine and were counted visually. Cooling was required to retard sample degradation. Sample sizes ranged from 1 to 50 cells with excitation times varying from 15 to 180 s. Excellent spectra have been obtained from 20 cells in 15 s using a spectrograph having only 3percnt; throughput.
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