Evaluation of 213-nm laser as an affordable alternative for the green elemental characterization of particulate matter on quartz fibre filters by laser ablation ICPMS

Abstract

Airborne particles, denoted as particulate matter (PM), are one of major environmental pollutants. Particles smaller than 10 µm (PM₁₀) penetrate into the human lungs during breathing and exert damage by physical and chemical mechanisms. PM mass concentration in the air and major toxicants contained are thus regulated by relevant directives all around the world, and their continuous monitoring is prescribed. Elemental composition of PM is one of the most often measured air-quality parameters, and the standard method for its determination produces huge amounts of toxic chemical waste. Sustainable alternatives are thus sought for, such as laser ablation inductively coupled plasma mass spectroscopy (LA-ICPMS), which allows for the direct analysis of PM collected on a filter without the microwave-assisted extraction step prior to the analysis with ICPMS. In this work, we evaluated the performance of 213 nm Nd:YAG laser system (LA213) compared to the more powerful 193 nm excimer laser (LA193) for this application, in order to facilitate the replacement of the standard method (i.e., MW/ICPMS) with a new, waste-free one. We show that LA213 produces good results when operated under optimized instrument conditions, which were in fact very similar to the LA193 system. Sensitivity for some elements was, however, a bit poorer, but this can be overcome with additional fine-tuning, if necessary. Wrapping-up our thorough evaluation, we can conclude that the more affordable LA213 is suitable for air-quality monitoring purposes.