Chapter 9 - LIBS application to liquid samples

Abstract

Liquid samples are usually classified as aqueous, nonaqueous, and mixtures. Examples of aqueous liquids are most often surface water, groundwater, drinking water, and wastewater, whereas nonaqueous liquids include organic solvents, oils, and many other hydrophobic liquids. Mixtures may be referred to as the combination of aqueous and nonaqueous liquids. Although most laser-induced breakdown spectroscopy (LIBS) research has been focused on the characterization of solid samples, the analysis of liquid samples by LIBS offers a huge potential in a number of applications such as surface and groundwater monitoring, oceanography, carbon dioxide (CO2) leak detection in geologic carbon storage, quality control in pharmaceutical and food industries, medical diagnostics, and industrial process monitoring. Traditionally, the analysis of liquid samples has been performed by well-established laboratory-based analytical techniques such as inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry. However, LIBS offers numerous advantages over the aforementioned techniques, including in situ and online measurements. Indeed, LIBS analysis is relatively fast, the instrumentation can be miniaturized to make the system portable, and the coupling of fiber optics allows LIBS measurements in harsh environments and places that are inaccessible by traditional lab-based techniques. In addition, only optical access to the sample is needed to perform a LIBS measurement to allow a standoff analysis. In this chapter, brief discussion on how LIBS can be applied for liquid sample analysis is presented.