Build-a-Bone: Development of a Matrix-Matched Reference Material for Quantitative Analysis of Bone with Portable LIBS

Abstract

With the rising popularity of laser-induced breakdown spectroscopy (LIBS) for studying skeletal samples, the need for a matrix-matched reference material for quantitative analysis of bone has come to light. Previous calibration materials used for laser-based sampling include glass standards, bone powders, carbonates, and hydroxyapatite standards, all of which fail to imitate the physiochemical matrix of bone samples. This study focuses on the development, characterization, and application of a matrix-matched reference material for bone. These materials are composed of a compact collagen scaffold that is embedded with strontium and barium doped hydroxyapatite crystals. Physical characterization of the composites indicates a hydroxyapatite crystallinity and pore size that corresponds to bone. Molecular characterization confirms the presence of hydroxyapatite and collagen throughout the material, while elemental analysis reveals a profile nearly identical to that of bone. Calibration curves for strontium and barium were developed for portable LIBS (pLIBS) analysis, finding LOD and LOQ values of 123 µg.g^-1 and 140 µg.g^-1 for strontium, and 29 µg.g^-1 and 37 µg.g^-1 for barium. Validation was performed on real-world bone fragments for which pLIBS signal was used to determine the concentration of strontium and barium.