Feasibility of an inexpensive single-particle SIBS instrument

This study evaluates spark-induced breakdown spectroscopy (SIBS) as an inexpensive and compact alternative to mass spectrometry and laser-based techniques for real-time elemental analysis of individual aerosol particles. In SIBS, an electrical spark generates a plasma that vaporizes and excites particles traversing the discharge region, enabling optical emission-based elemental detection. We developed and characterized a low-cost single-particle SIBS instrument incorporating an inductive spark generator and a spectrometer-based optical detection system. Plasma characterization showed a channel diameter of ∼0.1 mm, a lifetime of ∼1–3 ms, and a temperature of ∼3500 K, parameters that constrain analysis speed and elemental detectability. Experiments using monodisperse multi-salt aerosol particles demonstrate real-time detection of Na and K from individual particles. Particle–spark interaction probabilities were quantified using both a simplified computational model and experimental measurements, revealing their dependence on flow rate, spark energy, and particle size. Under typical test conditions (∼10 particles/cm3, 0.6 L/min flow, 10 Hz spark frequency), the system achieves hit rates on the order of 0.1/s, enabling practical analysis durations. The minimum detectable particle size is ∼2 µm, corresponding to estimated detection limits of ∼0.3 pg for Na and ∼4 pg for K. Although the relatively low plasma temperature restricts detection of higher-excitation-energy elements (e.g., Mg, Si, C), the results establish the capability of SIBS for elemental analysis of single airborne particles. The approach shows promise for low-cost industrial aerosol monitoring and classification of large ambient aerosol particles. Future improvements should aim at increasing plasma temperature and reducing the particle size detection threshold.