Parametric studies of liquid LIBS for agricultural applications

Abstract

Laser Induced Breakdown Spectroscopy (LIBS) is widely used in analytical chemistry, biomedicine, and environmental applications due to its real-time detection of multi-elements. However, the main challenge for LIBS application lies in its low detection sensitivity, especially for liquid sample analysis. When plasma is generated by a nanosecond laser pulse inside the liquid sample, fast quenching of the plasma occurs, and atomic emission intensity becomes weak with a short lifetime. Furthermore, the creation of surface fluctuations during laser ablation reduces the reproducibility of the signal. Researchers started exploring the possibility of improving the plasma signal by investigating different sampling approaches for liquids to increase the signal-to-background ratio of the signal. Liquid LIBS has the potential to become one of the best ultra-sensitive elemental characterization methods by standardizing the technique and making it applicable for potential industrial applications. In this context, this paper investigates two different sampling approaches for liquid LIBS signal enhancement. The experimental configurations, optimization of the experimental parameters, and the limit of detection of the sampling approaches of the proposed LIBS are detailed, followed by its potential application in vertical hydroponic farming.