NEW ULTRASENSITIVE DETECTOR FOR MICRO-SEPARATIONS

HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS AND MICROBORE LIQUID CHROMATOGRAPHY OFFER EXTREMELY HIGH EFFICIENCIES, ULTRA-SMALL SAMPLE INJECTION, AND SPEED OF ANALYSIS. HOWEVER, THE GENERAL UTILITY OF THESE NEW TECHNOLOGIES IS LIMITED BY THE SENSITIVITY OF THE DETECTOR. ULTRAVIOLET-TRANSMISSION DETECTORS ARE SHOWN TO BE INHERENTLY INCAPABLE OF THE SENSITIVITY AND DYNAMIC RANGE NECESSARY FOR A WIDE RANGE OF BIOCHEMICAL SEPARATION APPLICATIONS. VERY RECENTLY POTOMAC PHOTONICS, INC., INTRODUCED A SERIES OF SMALL, RELATIVELY INEXPENSIVE MID-TO-FAR-UV WAVEGUIDE EXCIMER LASERS. WE SHOW THAT THESE LASERS PROVIDE AN IDEAL PUMP SOURCE FOR A TECHNIQUE KNOWN AS CROSSED-BEAM PHOTOTHERMAL REFRACTION DETECTION. THIS TECHNIQUE HAS BEEN DEMONSTRATED CAPABLE OF \3 ORDERS OF MAGNITUDE BETTER SENSITIVITY THAN THE BEST UV-TRANSMISSION DETECTORS. NO CHEMICAL DERIVITIZATION OF THE ANALYTE IS NECESSARY TO ACHIEVE MAXIMUM SENSITIVITY. IN PHASE I, WE WILL BUILD A DETECTOR BASED ON PHOTOTHERMAL REFRACTION AND TO EMPLOY A PROPRIETARY KRYPTON FLUORIDE WAVEGUIDE EXCIMER LASER OPERATING AT 249 NM TO DEMONSTRATE DETECTION OF UNMODIFIED OLIGONUCLEOTIDES SEPARATED BY CAPILLARY ELECTROPHORESIS. WE INTEND TO DEMONSTRATE \100 TIMES GREATER SENSITIVITY THAN THAT AVAILABLE FROM UV-TRANSMISSION DETECTORS BEING USED FOR HPCE SYSTEMS. SUCH A DETECTOR WILL HAVE A BROAD ARRAY OF APPLICATIONS SUCH AS GENETIC TESTING AND ENGINEERING, PHARMACEUTICAL PURITY TESTING, AS WELL AS FORENSIC PATHOLOGY AND DNA FINGERPRINTING.