| As a difficult point in drug analysis,the separation and analysis of trace components in actual samples has been receiving much attention.Exploring extraction technology plays an important role in drug discovery,dosage form research,quality monitoring and metabolic analysis.Therefore,Separation and enrichment is a key step to improve sensitivity of complex matrix analysis.The study of extraction materials with high enrichment ability,safety and environmental protection is the most important.Magnetic graphene nanocomposites have a wide range of applications in the field of separation and enrichment due to their large surface area,large delocalized 7r-electron system,strong magnetic properties,excellent mechanical/thermal stability and easy processing.Magnetic graphene nanocomposites are developed for the analysis of traditional Chinese medicines and pesticide residues,which can be quickly separated with good selectivity and low interference.In this paper,the active constituents in natural medicines and pesticides were used as target analytes.A novel magnetic solid-phase extraction(MSPE)combined with HPLC has been developed.The major work contents include the following:(1)Determination of paeonol in medicine based on 2D magnetic graphene nanocomposite solid phase extraction-HPLCIn this paper,2D magnetic graphene nanomaterials(2D-Fe3O4@SiO2@G)was established as a new method for the determination of paeonol by solid phase extraction.The materials were characterized by infrared,transmission electron microscopy and isoelectric point.At 40℃ and pH=6.0,2D-Fe3O4@SiO2@G nanoparticles could rapidly and quantitatively adsorb paeonol.The extractants could be eluted with 6.0 mL of 1.5 mol L-1 NaOH solution in 1.0 min.Under optimised conditions,the detection limit of this method was 0.020μg mL-1,the linear range was 0.05-20.00μgmL-1 and the correlation coefficient(R2)was 0.9961.The real samples were analyzed and determined by the method.The results were satisfactory.(2)β-cyclodextrin-loaded magnetic graphene oxide nanocomposite for solid phase extraction of anthraquinone from Aloe vera and medicine by HPLCA method for the determination of anthraquinone(emodin,rhein)by using β-cyclodextrin-loaded magnetic graphene oxide nanomaterials(Fe3O4@SiO2@GO@β-CD)was established.The materials were analysed by using FT-IR,SEM,VSM and XPS.Fe3O4@SiO2@GO@β-CD nanoparticles could rapidly and quantitatively extract emodin and rhein at pH 6.0.Emodin,rhein were washed with 5.0 mL of 1.0 mol L"1 NaOH solution within 20 min.The experimental results displayed the enrichment factors of emodin and rhein were 8.0 and 10.0,respectively.The results showed the correlation coefficients(R2)were 0.9989-0.9993.The limits of detection were 0.020μg mL-1 for emodin and 0.043μg mL-1 for rhein.The linear range were 0.025-50.00μg mL-1 for emodin and 0.050-26.00μg mL-1 for rhein.The results were satisfactory.(3)Separation and analysis of Rutin in Lily and Serum by alanine-derived ionic liquid-loaded magnetic graphene oxide solid phase extraction-HPLCMagnetic graphene oxide nanomaterials and alanine-derived ionic liquid were as an efficient adsorbent for the determination of rutin in lily,tablets and mouse serum samples by using solid phase extraction technique combined with HPLC.The prepared Fe3O4@SiO2@GO@[C4mim]Ala was analysed by using Fourier transformed infrared spectroscopy(FT-IR),scanning electron microscopy(SEM)and vibrating sample magnetometer(VSM).Fe3O4@SiO2@GO@[C4mim]Ala nanoparticles could rapidly and quantitatively adsorb rutin in pH of 6.0.Rutin could be eluted from the extractants with 8.0ml of glacial acetic acid within 20 min.Under optimised conditions,the detection limit of this method was 2.0 ng mL-1,the linear range was 2.5-5.0×103 ng mL-1,the correlation coefficient(R2)was 0.9996 and the enrichment factor was 7.5.Lily,tablets and mouse serum samples were tested by this method.The results were satisfactory.(4)Separation and analysis of tebuconazole by HPLC with tryptophan-derived ionic liquid supported magnetic graphene oxide nanocompositesA method for the determination of tebuconazole by using tryptophan-derived ionic liquid-loaded magnetic graphene oxide nanomaterials(Fe3O4@SiO2@GO@[C4mim]Try)was established.Fe3O4@SiO2@GO@[C4mim]Try nanoparticles could rapidly and quantitatively adsorb tebuconazole at pH 7.0.Tebuconazole could been eluted from the extactants with 2.0 mL methanol in 3 min.The results showed that the detection limit of this method was 0.014 gg mL-1,the linear range was 0.016-40.00μg mL-1,the correlation coefficient(R2)was 0.9901 and the enrichment factor was 20.0.The water,rice,corn and soil samples were determined by this method successfully. |
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