Preparation And Application Of Novel Polymer Monolithic Columns In Drug Analysis

Due to the trace amount of target analytes and the complicated matrix in environmental and biological samples,sample pretreatment was often used to isolate pure,and enrich target analytes to improve analysis sensitivity and accuracy.As a kind of solid-phase microextraction,polymer monolithic column microextraction(PMME)possesses advantages of being solvent-saving or solvent-free,simple to operate,time saving and high performing.The stationary phase of PMME is critical in improving the extraction performance.However,because of the limited types of extraction media,it is necessary to develop different adsorbents with high extraction capacity and selectivity.In this paper,the preparation of new capillary polymer monolithic columns and their application in trace analysis in complex matrix were studied.The contents were as follows:1.The current status of solid-phase microextraction were reviewed;the application of monolithic column in sample pretreatment were discussed;the current status of polymer monolithic capillary column synthesis,functionalization,and their applications in sample pretreatment were previewed in detail.2.The preparation and application of a new poly(methacrylic acid-ethylene glycoldimethacrylate-N-vinylcarbazole)(poly(MAA-EGDMA-NVC))monolithic capillary column were developed.The monolith was prepared by the in situ thermal polymerization.It exhibited a homogeneous and continuous structure,good permeability,high extraction efficiency,and a long lifetime.Owing to the ? electrons,high stability and polar surface of N-vinylcarbazole(NVC),NVC-incorporated monolith showed a higher extraction performance than neat poly(MAA-EGDMA)because of the enhanced ?-? stacking interactions derived from the ?-electron-rich benzene functional from NVC.The enrichment factors of poly(MAA-EDMA-NVC)monolithic column for three BZPs were 59.2–68.1.A sensitive microextraction method based on the poly(MAA-EGDMA-NVC)monolithic column,coupled with gas chromatography(GC),was established for the determination of three BZPs.It showed wide linearity of 0.1–50 ng/m L and R2 ? 0.9965.The limits of detection(S/N = 3)of 0.011–0.026 ng/m L were obtained;and the limits of quantification(S/N = 10)of 0.036–0.088 ng/m L were obtained.This method was used for the BZPs analysis in urine and beer samples.The recoveries were 81.4–93.3% and 83.3–94.7% for the spiked samples,with relative standard deviations(RSDs)of 4.1–8.1% and 3.8–8.5%,respectively.This method provides an accurate,simple,and sensitive detection platform for drug analysis.3.The preparation and application of a new poly(N-vinylcarbazole-divinylbenzene)(poly(NVC-DVB))monolithic capillary column were developed.The monolith was prepared by the thermal polymerization.The polymerization was optimized mainly by changing the ratio of porogen content.The optimized polymer monolith had a homogeneous and continuous column bed,good permeability and mechanical stability.Poly(NVC-DVB)had good affinity to BZPs due to its through-pore structure and stong ?-? stacking interactions derived from the rich benzene functional groups in polymer.A method for the determination of six BZPs by poly(NVC-DVB)monolithic column microextraction followed by ultra-high-performance liquid chromatography and quadrupole Orbitrap high-resolution mass spectrometry(HPLC/MS)analysis was developed.Most of the six BZPs behaved linear dynamic range in 0.005–5 ng/m L,while 0.05–5 ng/mL for nitrazepam and 0.01–0.5 ng/mL for lorazepam,with coefficients of determination R2 ? 0.9991.The detection limits(LODs)were established in the range of 1.08–6.04 ng/L,and the quantification limits(LOQs)in the range of 3.60–20.1 ng/L.Finally,the proposed method was successfully applied to detecting six BZPs in human urine and beer samples.The percentages of extraction recovery were in the ranges of 79.6–95.2% for urine and 80.5–94.2% for beer.4.The preparation and application of a graphene monolithic column were developed using the ?-electron-rich poly(NVC-DVB)as a supporter.The content of graphene was optimized to obtain a homogeneous and stable 3D graphene monolithic column.More importantly,it retained the unique properties of graphene that associated with individual sheets,and the porous structure of polymer monolith.Based on the large delocalized ?-electron system,graphene can form ?-? stacking interactions with BZPs and benzene rings of poly(NVC-DVB),which bearing the enhanced adsorption capacity for BZPs comparied with neat polymer.A sensitive microextraction method based on the graphene monolithic column,coupled with HPLC/MS,was established for the determination of six BZPs.The optimized method gave the linear range of 0.005–1 ng/mL for nitrazepam,estazolam,chlordiazepoxide and alprazolam,0.01–1 ng/m L for lorazepam and midazolam,with R2 ? 0.9986,the detection limits of 1.12–2.35 ng/L,the quantification limits of 3.74–7.83 ng/L.Finally the method was successfully applied to separation and enrichment of six BZPs from urine and hair samples.The recoveries for spiked urine and hair were in the range of 78.6–85.6% and 87.2–94.3%,with the RSDs of 3.4–6.9% and 2.9–8.3%,respectively.It provided a sensitive method for drug analysis in biological samples.5.The preparation and application of a UiO-66/poly(NVC-DVB)monolithic column were developed.Zirconium-terephthalate-based UiO-66 has remarkable thermal and mechanical stability,and high surface area.It is also highly resistant to many organic solvents,acid and alkali.The content of UiO-66 was optimized to obtain a homogeneous and stable UiO-66/poly(NVC-DVB)monolithic column.The incorporation of UiO-66 improved the adsorption capacity for fungicides compared with neat polymer.A sensitive microextraction method based on the Ui O-66/poly(NVC-DVB)monolithic column,coupled with HPLC/MS,was established for the determination of five fungicides.The optimized method gave the linear range of 0.005–1 ng/m L for pyrimethanil,0.01–1 ng/mL for flutriafol,and 0.05–1 ng/m L for tebuconazole,hexaconazole and diniconazole,with R2 ? 0.9911,the detection limits of 1.34–14.8 ng/L,the quantification limits of 4.45–49.4ng/L.Finally the method was successfully applied to separate and enrichment of five fungicides from environmental water and soil samples.The recoveries were in the range of 78.6–85.6% and 87.2–94.3%,with the RSDs of 3.4–6.9% and 2.9–8.3%,respectively.It provided a sensitive method for fungicides analysis in environmental samples.