THE GLOBAL ENVIRONMENTAL RESEARCH COMMUNITY HAS URGENT NEED FOR AN AUTOMATED, STAND-ALONE AQUATIC NUTRIENT ANALYZER.

THE GLOBAL ENVIRONMENTAL RESEARCH COMMUNITY HAS URGENT NEED FOR AN AUTOMATED, STAND-ALONE AQUATIC NUTRIENT ANALYZER. PRELIMINARY STUDIES AT AERODYNE HAVE SHOWN THAT EXCIMER LASER VAPORIZATION OF WATER DROPLETS CAN BE ACHIEVED. SPECTRALLY RESOLVED EMISSION FROM DISSOLVED SPECIES OR THEIR EXCITED FRAGMENTS, CREATED BY THE VAPORIZATION LASER PULSE, HAVE ALSO BEEN OBSERVED. THESE PHENOMENA HOLD THE PROMISE THAT A VAPORIZATION/EMISSION STRATEGY CAN VE DEVISEDTO MONITOR CONCENTRATIONS OF AQUATIC NUTRIENTS SUCH AS NH4+, NO3-,N02-AND P03-AT REMOTE FIELD STATIONS WITHOUT OPERATORS OR SIGNIFICANT CONSUMPTION OF REAGENTS. THE RESEARCH DESCRIBED IN THIS PHASE I PROPOSAL IS AIMED AT OPTIMIZING AND MONITORING THE VAPORIZATION AND NUTRIENT FRAGMENT EMISSION PROCESS. SEVERAL APPROACHES TO MORE EFFICIENT COUPLING OF LASER ENERGY TO WATER ARE PROPOSED. THESE INCLUDE DIFFRACTION LIMITED BEAM QUALITY, RAMAN SHIFTING TO A MORE FAVORABLE WAVELENGTH, MULTIPLE PULSE WITHOPTIMIZED DELAY BETWEEN THEM AND THE ADDITION OF TRACE AMOUNTS OF MOLECULES OBSORBING AT THE LASER WAVELENGTH. THE MONITOR THE VAPORIZATION PROCESS, WE PROPOSE TO SEED THEWATER WITH AN EASILY DETECTABLE SPECIES, SUCH AS SODIUM ION.RESONANCE LAMP FLUORESCENCE CAN THEN BE USED TO MONITOR THE TIME EVOLUTION OF NEUTRAL SODIUM ATOMS. LASER INDUCED FLUORESCENCE WILL BE USED TO MONITOR VAPORIZATION OF THE NUTRIENT SPECIES.