Jhon Pareja

Laser ablation–laser induced breakdown spectroscopy for the measurement of total elemental concentration in soils

The performances of traditional laser-induced breakdown spectroscopy (LIBS) and laser ablation-LIBS (LA-LIBS) were compared by quantifying the total elemental concentration of potassium in highly heterogeneous solid samples, namely soils. Calibration curves for a set of fifteen samples with a wide range of potassium concentrations were generated. The LA-LIBS approach produced a superior linear response different than the traditional LIBS scheme. The analytical response of LA-LIBS was tested with a large set of different soil samples for the quantification of the total concentration of Fe, Mn, Mg, Ca, Na, and K. Results showed an acceptable linear response for Ca, Fe, Mg, and K while poor signal responses were found for Na and Mn. Signs of remaining matrix effects for the LA-LIBS approach in the case of soil analysis were found and discussed. Finally, some improvements and possibilities for future studies toward quantitative soil analysis with the LA-LIBS technique are suggested.

NO Mole Fraction Measurement in a Plasma-heated Auto Ignition Test Rig Using a 5.2 μm Interband Cascade Laser

In-situ concentration measurements of nitric oxide in the microwave-plasma-heated turbulent air-co-flow (800-1300 K) of an auto-ignition test rig have been performed, employing tunable diode laser absorption spectroscopy at a wavelength of 5.2 μm.