Laboratory evaluation of laser-induced breakdown spectroscopy (LIBS) as a new in situ chemical sensing technique for the deep ocean
Michel, Anna Pauline Miranda
MetadataShow full item record
Present-day expeditionary oceanography is beginning to shift from a focus on short- term ship and submersible deployments to an ocean observatory mode where long- term temporally-focused studies are feasible. As a result, a critical need for in situ chemical sensors is evolving. New sensors take a significant amount of time to develop; thus, the evaluation of techniques in the laboratory for use in the ocean environment is becoming increasingly important. Laser-induced breakdown spectroscopy (LIBS) possesses many of the characteristics required for such in situ chemical sensing, and is a promising technique for field measurements in extreme environments. Although many LIBS researchers have focused their work on liquid jets or surfaces, little at- tention has been paid to bulk liquid analysis, and especially to the effect of oceanic pressures on LIBS signals. In this work, laboratory experiments validate the LIBS technique in a simulated deep ocean environment to pressures up to 2.76 × 107 Pa. A key focus of this work is the validation that select elements important for understand- ing hydrothermal vent fluid chemistry (Na, Ca, Mn, Mg, K, and Li) are detectable using LIBS. A data processing scheme that accurately deals with the extreme nature of laser-induced plasma formation was developed that allows for statistically accu- rate comparisons of spectra. The use of both single and double pulse LIBS for high pressure bulk aqueous solutions is explored and the system parameters needed for the detection of the key analytes are optimized. Using both single and double pulse LIBS, the limits of detection were found to be higher than expected as a result of the spectrometer used in this experimentation. However, the results of this validation show that LIBS possesses the characteristics to be a viable chemical sensing method for in situ analyte detection in high pressure environments like the deep ocean.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2007
Showing items related by title, author, creator and subject.
McDermott, Jill M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2015-02)This thesis examines the controls on organic, inorganic, and volatile species distributions in hydrothermal fluids venting at Von Damm and Piccard, two vent fields at the ultraslow spreading Mid-Cayman Rise, Earth’s deepest ...
Workman, Rhea K. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2005-06)This thesis uses trace elements and radiogenic isotope tracers to define elemental abundances in reservoirs of the Earth's mantle, including EM2 (the Enriched Mantle 2), as seen in the Samoan hotspot track, and DMM (the ...
Murray, James W. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1973-06)An experimental study of the interaction of metal ions with the surface of hydrous manganese dioxide has been completed. The results of these experiments have greatly improved our qualitative understanding of the adsorption ...