A bio-sorbent based on polylactic acid nanocomposites for thin-film microextraction

In this work, a micro-solid-phase extraction technique employing polylactic acid (PLA)/ZnO-chitosan bio-nanocomposites was developed to isolate selected triazines from aqueous environments. Subsequently, the isolated analytes were injected into gas chromatography-mass spectrometry instrument following solvent desorption. The PLA bio-nanocomposites, incorporating varying concentrations of synthesized ZnO-chitosan, were fabricated utilizing the solvent casting method. The PLA/ZnO-chitosan bio-nanocomposites and ZnO-chitosan hybrid nanoparticles were analytically characterized by the use of field emission scanning electron microscopy, Fourier-transform infrared spectroscopy, tensile testing, and X-ray diffraction. Tensile tests showed that adding ZnO-chitosan hybrid nanoparticles to PLA increased both its tensile strength and elongation at break. Key parameters of the extraction process involving PLA/ZnO-chitosan bio-nanocomposites such as nanoparticle concentration, ionic strength, sample pH, extraction duration, and solvent choice were meticulously examined and optimized. The refined extraction device exhibited high sensitivity and rapidity, achieving analytical parameters with a detection limit ranging from 0.85 to 2.5 ng L-1 and a quantification limit between 5 and 10 ng L-1. Equilibrium was attained within 20 min. Over a concentration range of 10-1000 ng L-1, the method showed linearity, with a correlation value higher than 0.9997. Having a relative standard deviation between 4 and 8%, repeatability was confirmed at 100 ng L-1. Ultimately, the proposed extraction device's effectiveness was confirmed by successfully recovering specific analytes from natural water samples, with relative recovery percentages ranging from 98 to 102%, indicative of negligible matrix interference.