Miniaturized matrix solid-phase dispersion based on deep eutectic solvent and carbon nitride associated with high-performance liquid chromatography: A new feasibility for extraction and determination of trace nitrotoluene pollutants in soil samples.

In this research, a miniaturized version of matrix solid phase dispersion (MSPD) method was developed for successful extraction of five nitrotoluenes from soil samples. The terpene based deep eutectic solvent (DES) composed of borneol and DL-menthol was used simultaneously as extraction solvent and dispersing liquid. Graphitic-carbon nitride (g-C3N4) as sorbent was prepared by pyrolysis of melamine at a muffle furnace. The MSPD mixture was obtained by grinding soil, DES, and g-C3N4. Minimum amount of acetonitrile was used in the elution step. Some experimental variables including type and volume of DES, type of dispersant, mass ratio of dispersant to sample, volume of elution solvent, grinding time, and ultrasonication time were evaluated. Analysis of extracted samples was performed by high performance liquid chromatography-ultra violet detection. Under the optimized conditions; the limits of detection were achieved in the range of 0.12-0.33 μg g-1, and the relative standard deviations were equal to or lower than 9.3%. The extraction recoveries were ranged from 78 to 96%. This straightforward and fast method is effective for environmentally friendly extraction of nitrotoluenes from soil samples.