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This paper reports a new variant of sample clean-up procedure based on miniaturized matrix solid phase dispersion (MSPD) combining with water compatible magnetic molecularly imprinted polymers (MMIP) for preconcentration of melamine from milk samples prior high-performance liquid chromatography with UV detection. By employing MMIP as dispersant sorbent matrix interferences could be eliminated completely and the column packing step was interestingly omitted that decreasing in glassware expenditure, labor effort and extraction time which cause improvement of the method performance. In order to investigate the functionality, morphology and magnetic properties of the prepared MMIP, it was fully characterized by FT-IR, VSM, SEM, and TEM. Multivariate optimization was applied as a versatile statistical approach for evaluating the influence of the main variables and their interactions on extraction efficiency. Under optimized conditions, the proposed method exhibited a wide linear response in the concentration range of 250.0–5000.0 μg L−1, satisfactory recoveries for all samples (86.6% ≤), and supreme repeatability (RSD less than 6.3%) were achieved as well. The low limit of detection close to 67.0 μg L−1 implied high ability of proposed method for isolation of melamine from complicate milk sample. These befitting results demonstrated that the developed method is unique in terms of the facility, rapidly and least solvent consumption as well as accurate analysis of melamine at trace levels.

In the present work, hollow porous molecularly imprinted polymer (HPMIP) was prepared via adopting a sacrificial support approach using glibenclamide (GB) as template, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate as cross-linker (EGDMA) and mesoporous MCM-48 nanospheres as support. Owing to a short thickness of the foresaid HPMIP, a suitable steric structure was readily available that lead to fast and effective mass transfer of target analyte to sorbent and consequently supply high binding capacity. After ultrasonic-assisted dispersive solid phase extraction of urine sample, the analyte of interest was quantitatively pre-concentrated and determined by high performance liquid chromatography-ultraviolet detection (HPLC-UV). Influence of factors affecting the extraction efficiency such as sonication time, sample pH, sorbent dosage, and volumes of eluent and washing agents as well as their significant interactions were simultaneously optimized by experimental design methodology. Under optimized conditions, present method has linear response over concentration range of 10.0-3000.0μgL-1 in human urine samples with a satisfactory detection limit close to 3.5μgL-1. The inter-day precisions of the current method (coefficient of variation) are lower than 5%, while recoveries are more than 89.5%.