LEAPS-MPS: Cutting Edge Calibration for the Direct Determination of Trace Analytes using Laser-Induced Breakdown Spectroscopy

In this project funded by the MPS-LEAPS (Launching Early-Career Academic Pathways) Program and the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, Professor Willis Jones and his students at the University of North Florida will perform studies to improve the determination of trace level analytes using laser-induced breakdown spectroscopy (LIBS). LIBS is a versatile measurement technique capable of directly measuring solids, liquids, and gases with minimal preparation. A high-powered laser forms a small plasma that is used to quantify all elements present in a sample. However, the method is inherently very “noisy” and often provides results with poor reproducibility. Furthermore, the makeup of a sample (soil versus wastewater, for example) can ruin any attempt at measuring trace level analytes. Professor Jones and his students will construct a custom LIBS system and develop novel calibration strategies that attack both of these limitations. Their studies could result in calibration strategies that broadly improve LIBS measurements and extend beyond the LIBS space, leading to improved trace level quantification for all analytes of interest in innumerable fields of science. In addition, LIBS technology will lead to closely mentored research projects for undergraduate students and will be incorporated into the core curriculum at UNF, continually training new generations of budding scientists and enhancing their technical capabilities as increasingly essential and rapidly growing fields of research become more prevalent. Professor Jones and his students will develop novel, matrix-matched trace analyte calibration strategies that build upon the idea of standard dilution analysis (SDA), which has been shown to improve analytical accuracy and precision of calibrations while also correcting for all sample matrix effects, directly addressing the traditional limitations of LIBS. Initial investigations will focus on the direct analysis of liquid samples, beginning with preprepared static solutions before moving to flowing, on-line dilutions. All proposed liquid LIBS measurements will be performed using two methodologies: (1) introduction of prepared liquids into a pneumatic nebulizer, with the laser focused into (thus forming the plasma in) the generated aerosol (akin to sample introduction in workhorse analytical inductively coupled plasma (ICP) type measurements for trace analytes in solution) and (2) focusing the laser onto the surface of (or into) a bulk liquid. Successful proof-of-concept using SDA for trace level determinations using LIBS in liquids samples will be a significant improvement in LIBS calibration, and the principles investigated in this research will ultimately be extended and adapted for the direct analysis of solids. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.