Porous Chitosan Composite Membrane Tandem Laser-Induced Breakdown Spectroscopy for Detection of Metal Elements in Liquid Samples

Laser-induced breakdown spectroscopy (LIBS) is currently one of the most popular techniques for direct element analysis of solid samples. However, when directly used for liquid sample analysis, there are disadvantages, including sample splashing, plasma quenching, and poor signal stability. These problems can be overcome through liquid-solid matrix conversion; at the same time, LIBS signal enhancement can be realized, and the sensitivity of detection of liquid samples can be improved. For this research, the authors used chitosan (CS) as a raw material, and introduced poly(vinyl alcohol) (PVA) and polyethyleneimine (PEI) to finally synthesize a new type of porous membrane material with better stability and more functional group content. The membrane was used as a liquid-solid conversion matrix material combined with LIBS technology to successfully achieve rapid separation and detection of Cu, Ag, Pb, and Cr, and the corresponding detection limits can reach 0.038, 0.069, 0.012, and 0.009 mg/L, respectively. This method further improves the sensitivity of the LIBS method. Combining it with membrane materials will replace inactive membranes and open up a new way for the rapid analysis of solution samples using LIBS technology.