Development of magnetic matrix solid phase dispersion method for the extraction of crystal violet and rhodamine B from sediments based on magnetic ZIF-8 and a deep eutectic solvent

A magnetic matrix solid phase dispersion (MSPD) method based on magnetic ZIF-8 (SDS@MZIF-8) and a deep eutectic solvent was developed and used to the extraction of crystal violet and rhodamine B in lake sediments. SDS@MZIF-8 was prepared and used as the extraction sorbent and dispersant in MSPD. The magnetic property of MZIF-8 facilitated the recovery of the extraction sorbent after the blending step. Hydrophilic deep eutectic solvents were prepared and used as efficient green dispersing solvents in MSPD. The use of magnetic sorbent in MSPD is simple and fast, eliminating some additional steps commonly used in the classical MSPD and shortening the extraction time. The parameters influencing the extraction efficiency were investigated and optimized. Under the optimized conditions, the intra- and inter-day relative standard deviations were less than 4.9 %. The linearity ranged from 2-400 µg g −1 with coefficients of determination higher than 0.9943. The detection and quantification limits of RB and CV varied between 0.3–0.5 μg g −1 and 1.0–1.8 μg g −1 , respectively. Finally, the developed method was applied to the analysis of RB and CV in the sediment samples. The recoveries ranged from 93.2 to 107.3 % and the relative standard deviations ranged from 0.8 to 4.9 %. The results suggest a high potential use of the proposed method to determine the organic pollutants in solid samples. Compared with the conventional MSPD extraction technique, the developed method considerably reduced the sample and solvent consumption, offering important environmental benefits.