Note: A novel technique for analysis of aqueous solutions by laser-induced breakdown spectroscopy

Abstract

Surface-enhanced Raman spectroscopy (SERS) substrates typically consist of gold or silver nanoparticles deposited on a non-conductive substrate. In Raman spectroscopy, the nanoparticles produce an enhancement of the electromagnetic field which, in turn, leads to greater electronic excitation of molecules in the local environment. Here, we show that these same surfaces can be used to enhance the signal-to-noise ratio obtained in laser-induced breakdown spectroscopy of aqueous solutions. In this case, the SERS substrates not only lower breakdown thresholds and lead to more efficient plasma initiation but also provide an appropriately wettable surface for the deposition of the liquid. We refer to this technique as surface-enhanced laser-induced breakdown spectroscopy.

Nanoparticle enhanced laser induced breakdown spectroscopy of liquid samples by using modified surface-enhanced Raman scattering substrates

“…), the achieved magnitude of signal enhancement is reasonable for a routine LIBS instrument, and is also similar to values reported in other NELIBS studies for Ag NPs (e.g. [ 2,7]). Please also note that 3.) that show a monotonous decrease as a function of both variables.…”

“…ms), only smaller signal enhancement factors can be attained [3,5] and that the enhancement also depends on the excitation potential of the electronic transition of the element studied [2][3][4]. It was also demonstrated that the NELIBS analysis of liquid samples is also possible, if they are dried onto substrates formerly prepared by NP deposition [4,6,7] or by NP embedding [11].…”

“…In later years, the NELIBS approach has been studied in detail by the inventors and other researchers (e.g. [3][4][5][6][7][8][9][10][11]). It was shown, that the metal the NPs are made of, the surface concentration, as well as the laser wavelength and irradiance all have a great impact on the signal enhancement achievable [3].…”

Perspective on the use of nanoparticles to improve LIBS analytical performance: nanoparticle enhanced laser induced breakdown spectroscopy (NELIBS)

“…for enhancing the signal of analytes deposited on top of the NP layer, rather than that of substrates below them, as in the examples discussed so far. This is for example the case of the analysis of micro-drops of liquid solutions [24,25]. As it is well-known, solutions can be successfully analyzed with LIBS either directly in the liquid phase by Double Pulse (DP) techniques or by depositing and drying drops of solution on a substrate.…”

Detecting and Mapping Harmful Chemicals in Fruit and Vegetables Using Nanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy

“…First, the nanoparticles may increase the number density of particles of the sample in the ablation process 39 . Second, the nanoparticles may decrease the ablation threshold 40 . NELIBS can allow trace chemicals in fruit and vegetables to be detected at concentrations that cannot be detected using the ordinary LIBS method.…”