Laser-induced breakdown spectroscopy for phosphorus analysis: current challenges and critical perspectives

Phosphorus is essential for global food security as an irreplaceable component of fertilizers, and it also finds widespread application across numerous industrial and technological fields. Because of its critical role and the significant risk of supply shortages, the European Commission has designated phosphorus as a critical raw material. Consequently, there is a growing need for fast, robust, and adaptable analytical techniques capable of accurately determining phosphorus in environmental, agricultural, industrial, and recycling contexts. Among these, Laser-Induced Breakdown Spectroscopy (LIBS) has gained prominence, offering multi-element capability, minimal sample preparation requirements, and the ability to perform in situ and real-time analyses. This review provides a comprehensive overview of the experimental methodologies and analytical strategies for LIBS-based phosphorus quantification across a wide range of matrices, including soils, rocks, fertilizers, biological samples, industrial materials, and secondary resources. Particular emphasis is placed on the current challenges associated with phosphorus analysis by LIBS, including matrix effects, calibration transferability, and the reliability of advanced chemometric and machine-learning approaches. The review also discusses recent progress in calibration methods, signal-enhancement techniques, handheld instrumentation, and strategies aimed at improving analytical robustness and reducing matrix-related effects. By critically assessing both recent advances and persisting limitations, the review highlights the growing relevance of LIBS as a powerful analytical tool for sustainable phosphorus management and the development of circular-economy initiatives, while also providing critical perspectives on the future evolution of the technique for reliable phosphorus quantification.