Single particle laser-induced breakdown spectroscopy for elemental analysis of water and bioaerosols
|Kustantaja||Tampere University of Technology|
|Tila||Julkaistu - 22 huhtikuuta 2016|
|Nimi||Tampere University of Technology. Publication|
Two novel methods for improving the sensitivity of LIBS of dissolved elements were introduced in this Thesis. In the presented techniques, aerosol particles generated from the sample solution are analyzed individually with LIBS. The main beneﬁts of single particle LIBS are the high preconcentration of the sample and the absence of the liquid matrix which suppresses the LIBS signal. In the ﬁrst instrumentation, the particle travels along a narrow carrier gas ﬂow and its presence in the small sampling volume is determined by an optical sensor. In the second presented technique, the generated droplet is trapped in three dimensions using electrodynamic balance (EDB) technology and the residual particle is analyzed after the complete drying of the droplet. A detailed characterization of LIBS of precisely trapped particles was also conducted in this Thesis. Clear improvement with respect to reproducibility and sensitivity was achieved in this work compared with the direct LIBS analysis of water. The limits of detection for the constructed EDB-LIBS system were at 50 µg/l level for several transition metals and are among the lowest values obtained with LIBS based trace element analysis. The ﬂexible requirements for the LIBS laser pulse energy and the speed of operation improve the applicability of the aerosol based sample preparation to the monitoring of industrial and natural waters. Moreover, the concurrent detection of dissolved elements and microbiological contamination of water was demonstrated by the combination of laser-induced ﬂuorescence and single particle LIBS.