Abstracts: 



Mapping 



Instrumentation 



Quantitation in Electrophoresis Based on Lasers 



E. S. Yeung 



Environmental Sciences Program, Ames Laboratory, Ames, lA 5001 1 

 (515)294-8062 



The goal of this project is to develop a novel laser-based imaging technique for 

 quantitation in gel electrophoresis and in capillary electrophoresis. No stains are 

 required: thus cost-efficiency, reliability, convenience, and speed of processing are 

 increased. The fact that the scanning technique uses no mechanical parts adds to the 

 positional accuracy (resolution) of the measurement. The research is based on indirect 

 fluorometry and acousto-optic imaging. In indirect fluorometry, a fluorescing ion is 

 used to elute the sample and thus produce a large fluorescence background signal 

 throughout the gel. When one of the components of the samples appears, the fluore.scing 

 ion is displaced; a lower fluorescence signal will then be observed. Since electro- 

 phoresis is based on charged species, electroneutrality requires a one-to-one 

 displacement of the fluorescing ion. This negative signal allows nonfluorescing species 

 to be detected with the high sensitivity nonnally associated with fluorescing species 

 only, and without staining. The response should be uniform and predictable because it is 

 derived from the same fluorescing ion. Preliminary results indicate that indirect 

 fluorometry is feasible for monitoring nucleotides and DNA fragments. Applications to 

 DNA mapping and sequencing will be pursued. 



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