Reagentless water and surface sensors employing laser induced native fluorescence (LINF) and resonance Raman spectroscopy (RRS) in the deep UV are making significant progress in detecting chemical and biological targets and differentiating them against a wide range of background materials. Methods for optimizing sensor performance for specific target and backgrounds materials will be discussed in relationship to closed industrial environments and open natural environments. Limits of detection and chemical specificity will be discussed for high and low spectral resolution systems for a wide range of compounds and composite particles such as spores and cells. Detection and identification of single spores at working distance of several meters is illustrated.
A range of sensors will be described along with their physical and performance specifications including sample, sipper and immersion sensors for water and fixed point and scanner systems for surfaces. In addition, the use of UV LINF and RRS for detection in capillary electrophoresis and liquid chromatography will be described with limits of detection in the range of a few nmol L<sup>-1</sup>.
We are developing a submersible deep ultraviolet laser induced native fluorescence (UVLINF) instrument to detect and identify trace levels of chemicals of life and other organic chemicals in water column of lakes and ocean. The instrument can also measure and log temperature, pressure and conductivity of the ambient water environment. The instrument is solar-blind and can operate up to depths of few hundred meters. The proposed concept uses a 224.3nm laser to excite and measure fluorescence in multiple UV and visible wavebands as a function of depth in a body of water. These fluorescence measurements can then be interpreted to classify organic material discovered during submersion of the instrument. The fluorescence instrument has the advantage that very sensitive measurements can be made in microseconds so that vertical profiling of a body of water can be done rapidly. The instrument also can be used for fast analysis of water quality from different sources.