基于SiO(2)@Fe(3)O(4)的磁性纳米材料分离富集谷物中痕量黄曲霉毒素B(1)

In this study, a magnetic nanomaterial antibody (Ab)-SiO(2)@Fe(3)O(4) was synthesized, which was employed to absorb aflatoxin B(1) (AFB(1)) in complicated grain matrices. The Ab-SiO(2)@Fe(3)O(4) material was then paired with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for subsequent accurate detection. The Ab-SiO(2)@Fe(3)O(4) material has a specific adsorption capacity for AFB(1) because of the stable and specific biological binding between antigen and antibody. This process can achieve the identification between the material and food matrix quickly, thereby completing the separation and enrichment process. Then, high sensitivity and high accuracy HPLC-MS/MS were employed for signal readout and actual quantification, which can significantly increase the detection efficiency and enable high-throughput detection of numerous samples. In the pretreatment process, Fe(3)O(4) was first synthesized by microwave-assisted hydrothermal synthesis within 1 h, and Ab-SiO(2)@Fe(3)O(4) was then produced using the enhanced Stober’s approach. This material with high adsorption performance was synthesized under relatively mild conditions and short time. To obtain Ab-SiO(2)@Fe(3)O(4) materials with uniform particle size, magnetic properties, and dispersibility that met the requirements, synthesis conditions of Ab-SiO(2)@Fe(3)O(4) and conditions for capturing the AFB(1) target were analyzed. The findings demonstrated that the best effect was obtained when the dosage of FeCl(3)·6H(2)O was 10.0 mmol, the heating time was 40 min, and 100 μL tetraethoxysilane was employed for SiO(2) coating. The AFB(1) antibody was then combined with the surface of SiO(2)@Fe(3)O(4) under several conditions. The findings revealed that the best coupling efficiency of Ab could be obtained when the concentration of 2-morpholinoethanesulfonic acid monohydrate (MES) was 10 mmol/L, pH was 6.5, and the molar ratio of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC)∶N-hydroxysuccinimide substances (NHS) was 2∶1. The coupling buffer was then selected as phosphate buffer (PBS) with pH=7.4, and 8 mg Ab-SiO(2)@Fe(3)O(4) was employed to separate and enrich AFB(1) at 37 ℃ for 10 min. In the actual detection, acetonitrile-water-formic acid (85∶10∶5, v/v/v) was employed as the extraction solution. After ultrasonic extraction for 10 min, Ab-SiO(2)@Fe(3)O(4) was employed to separate and enrich AFB(1) in the extract. The supernatant was dried with nitrogen and reconstituted with 1-mL acetonitrile. The solution was then filtered through a 0.22 μm filter and detected using HPLC-MS/MS, thereby realizing the quick and quantitative detection of AFB(1). AFB(1) had an excellent linear relationship in the range of 2-50 μg/L under the optimal analytical conditions, and the correlation coefficient was less than 0.99. The LOD was 0.04 μg/kg, and the LOQ was 0.13 μg/kg. The spiked recoveries of AFB(1) in three grain matrices ranged from 76.21% to 92.85% with RSD≤5.29% at four different spiked levels. The approach was applied to the determination and analysis of AFB(1) in 30 real grain samples of rice, corn, and wheat. The findings demonstrated that AFB(1) was detected in one wheat sample and two corn samples, and its content was 0.38, 0.13, and 0.47 μg/kg, respectively, and no toxins were found in other samples. The approach combined Ab-SiO(2)@Fe(3)O(4) magnetic nanomaterials with HPLC-MS/MS, which could obtain high-efficiency separation and enrichment of AFB(1). Furthermore, the low-cost Ab-SiO(2)@Fe(3)O(4) could be stored for more than a week and complete the pretreatment process within 30 min. This effective pretreatment process combined with HPLC-MS/MS could realize the analysis of several samples within a short time, and had a promising application prospect in the detection of AFB(1) in grains.