Facile synthesis of magnetic molybdenum disulfide@graphene nanocomposite with amphiphilic properties and its application in solid-phase extraction for a wide polarity of insecticides in wolfberry samples.

A novel magnetic molybdenum disulfide@graphene (Fe3O4/MoS2@G) nanocomposite with amphiphilic properties was prepared via a co-mixing solvothermal method. To demonstrate the feasibility of Fe3O4/MoS2@G as a sorbent during sample preparation, it was employed for the magnetic solid phase extraction (MSPE) of ten pyrethroids, three triazoles and two acaricide pyridaben and picoxystrobin in an emulsified aqueous solution. Dichloromethane was used as the extractant to form an emulsified aqueous solution. Subsequently, the Fe3O4/MoS2@G sorbent with amphiphilic properties was used to retrieve 15 wide polarity insecticides from dichloromethane via MSPE. The proposed method has the advantage of being applicable to different polar pesticides, strengthening the capacity of enrichment and purification of target analytes. The π-π interaction between the hydrophilic and hydrophobic moieties of Fe3O4/MoS2@G and the aromatic rings of target analytes were responsible for the efficient sorption. Thus, a reliable, convenient, and efficient method for the analysis of 15 insecticides with wide polarity in wolfberry samples was established by coupling Fe3O4/MoS2@G nanocomposite MSPE with gas chromatography-mass spectrometry (GC-MS) analysis. The obtained linearity of this method was in the range from 1 to 5000 ng mL-1 for 15 analytes, with determination coefficients (R2) ≥0.9907. The limit of detection (LOD) for 15 insecticides was in the range from 0.1 to 5.0 ng g-1. The recoveries of 15 insecticides from spiked wolfberry samples were in the range from 71.41% to 110.53%, and RSD was less than 14.8%.