Organically Modified Aerogel For In-tube Solid-phase Microextraction

Sample preparation has become a key part of the analytical process due to its diversity and complexity of the sample matrix and low number of analytes in components.An effective sample pretreatment technology can reduce the interference of impurities,enrich trace components,and improve the sensitivity of analytical methods.Solid-phase microextraction(SPME)is a kind of sample pretreatment technology,which integrates sampling,extraction,concentration and sample introduction.It has the advantages of simple operation,high precision and easy to realize online analysis with other analytical instruments.Conventional SPME is suitable for the determination of low boiling point and high thermal stability compounds by gas chromatography(GC),but it is difficult to achieve effective enrichment analysis for most high boiling point and thermal instability compounds.SPME can be used in combination with high performance liquid chromatography(HPLC)for the extraction and analysis of most target analytes.Fiber in-tube SPME is a form with distinctive feature of SPME.It is not only increases the extraction area,reduce the dead volume inside the tube,increase the extraction efficiency and enhance the accuracy of analysis.However,the factors of coating types,poor selectivity and short service life can limite the development of in-tube SPME.Aerogel is a kind of three-dimensional nano network porous material with excellent properties,huge surface area and abundant species takes some good application in the field of in-tube SPME.In this paper,the organic modified aerogels were prepared on the surface of basalt fibers(BFs)and titanium wire,and filled into into PEEK tube to be applied for simultaneously analyzing polycyclic aromatic hydrocarbons(PAHs)and estrogen compounds in environmental samples with good repeatability,recoveries and chemical stability.The main research contents and results are as follows:1.A isophthalaldehyde modified melamine-formaldehyde aerogel was prepared on the BFs,and filled into PEEK tube coupled to HPLC.The general morphology and surface properties of the BFs and aerogel were characterized by scanning electron microscopy and fourier transform infrared spectrometer.An online in-tube SPME-HPLC analysis method was established and afforded wide linear ranges(0.03-100 ?g L-1),low limits of detection(0.01-0.05 ?g L-1)and acceptable extraction repeatability(1.9-3.9% and 3.9-7.4%).The method was successfully applied to determination of eight PAHs in real samples.2.A novel organically modified silica aerogel was functionalized on the BFs and filled into the PEEK tube coupled with HPLC for in-tube SPME.The morphology and surface properties of the prepared silica aerogel was characterized by scanning electron microscopy and fourier transform infrared spectrometer.The effects of extraction sampling rate,sample volume,organic solvent content,ionic strength,p H value and desorption time on extraction and elution efficiency were investigated.Under the optimal conditions,a sensitive,automation and selective method was developed for the determination of five estrogens.The linear coefficient of the working curve of each material was 0.9991-0.9998,the linear range was 0.03-100 g L-1,the detection limit was between 0.01-0.03 g L-1.Finally,the developed method was successfully applied to the determination of estrogens in real samples.3.A polyurethane modified silica aerogel was functionalized on the BFs and filled into the PEEK tube coupled with HPLC for in-tube SPME.The effects of extraction sampling rate,sample volume,organic solvent content,ionic strength,pH value and desorption time on extraction and elution efficiency were investigated.Under the optimal conditions,a sensitive,automation and selective method was developed for the determination of five estrogens.The linearity was 0.10 to 50 ?g L-1 and 0.03 to 100 ?g L-1 with correlation coefficients ranging from 0.9991 to 0.9996,and low detection limits were 0.01 to 0.05 ?g L-1.Finally,the developed method was successfully applied to the determination of estrogens in real samples.4.A poly(dopamine)modified graphene aerogel was prepared on the titanium wire,and they were filled into PEEK tube coupled to HPLC.Under the optimal conditions,an online in-tube SPME-HPLC analysis method was established and afforded wide linear ranges(0.03-50 ?g L-1),low limits of detection(0.01-0.05 ?g L-1),acceptable extraction repeatability(0.77-3.65%).The method was successfully applied to determination of eight PAHs in two real samples.