Simultaneous Determination of Four Plant Hormones in Soil by Ultrasound-Assisted Ionic Liquid Based Dispersive Liquid-Liquid Microextraction

Amino-modified Scholl-coupling mesoporous polymer for online solid-phase extraction of plant growth regulators from bean sprouts

A new amino-modified Scholl-coupling mesoporous polymer (NH₂@SMPA)-online solid-phase extraction method, coupled with high-performance liquid chromatography (online SPE-HPLC) was established for the analysis of six plant growth regulators (PGRs) in bean sprouts. NH₂@SMPA was synthesized by acid-catalyzed deacetylation of acetylamino-Scholl-coupling mesoporous polymer (SMPA). The diversity of functional groups, such as aromatic, acetylamino, and NH₂, was conducive to multiple binding interactions between NH₂@SMPA and PGRs. NH₂@SMPA exhibited superior extraction capability for PGRs, compared with SMPA and commercial adsorbents. The extraction conditions, including loading solvent, pH of loading solution, eluting solvent, and flow rates of loading and elution, were optimized. Under the optimized conditions, wide linear ranges (0.01-500 μg kg^-1) and low detection limits (2.34-20.2 ng kg^-1) were obtained. The recoveries were satisfactory, i.e., 86.0% to 109% with relative standard deviations ≤9.8% (n = 3). Finally, the online SPE-HPLC method was successfully used for determination of PGRs in bean sprouts.

Ionic Liquid-Hybrid Molecularly Imprinted Material-Filter Solid-Phase Extraction Coupled with HPLC for Determination of 6-Benzyladenine and 4-Chlorophenoxyacetic Acid in Bean Sprouts

A new method involving ionic liquid-hybrid molecularly imprinted material-filter solid-phase extraction coupled to high-performance liquid chromatography (IL-HIM-FSPE-HPLC) was developed for the simultaneous isolation and determination of 6-benzyladenine (6-BA) and 4-chlorophenoxyacetic acid (4-CPA) in bean sprouts. Sample preconcentration was performed using a modified filter, with the new IL-HIM as the adsorbent, which shows double adsorption. The first adsorption involves special recognition of molecular imprinting, and the second involves ion exchange and electrostatic attraction caused by the ionic liquid. This method combines the advantages of ionic liquids, hybrid materials, and molecularly imprinted polymers and was successfully applied to determine 6-BA and 4-CPA in bean sprouts. The adsorption of 6-BA to IL-HIM is based on selective imprinted recognition, whereas the adsorption of 4-CPA is mainly dependent on ion-exchange interactions.