2,4,6-trichlorophenol molecularly imprinted suspension polymer has been prepared and applied to the molecularly imprinted micro-solid-phase extraction procedure for selective preconcentration of phenolic compounds fro...2,4,6-trichlorophenol molecularly imprinted suspension polymer has been prepared and applied to the molecularly imprinted micro-solid-phase extraction procedure for selective preconcentration of phenolic compounds from environmental water samples. The influence of functional monomer, cross-linker, polymerization condition, porogen, and the ratio of template molecule and functional monomer to cross-linker on the size of the obtained particles were investigated. It was found that methyacrylic acid as functional monomer, divinylbenzene as cross-linker, the molar ratio of template molecule and functional monomer to cross-linker was 1:4:20, the amount of AIBN was 100 mg, ultraviolet radiation at 365 nm were the optimal conditions, and at these conditions, the polymers had the best adsorption efficiency and had the monodispersity of 2 - 3 μm microsphere particles. The characteristics of the MIMSPE method were valid by high performance liquid chromatography. This MIMSPE-HPLC method has been successfully applied to the direct preconcentration and determination of phenolic compounds (phenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol) in environmental water samples.展开更多
该研究旨在分析不同产区修水宁红茶的香气组分及感官品质差异,探讨产区对其品质的影响。采用顶空固相微萃取-气相色谱-质谱联用技术(headspace solid-phase microextraction and gas chromatography mass spectrometry,HS-SPME-GC-MS)分...该研究旨在分析不同产区修水宁红茶的香气组分及感官品质差异,探讨产区对其品质的影响。采用顶空固相微萃取-气相色谱-质谱联用技术(headspace solid-phase microextraction and gas chromatography mass spectrometry,HS-SPME-GC-MS)分析3个产区的修水宁红茶香气组分,并运用主成分分析(principal component analysis,PCA)和偏最小二乘判别分析(partial least squares discrimination analysis,PLS-DA)评估产区对香气组分的影响,结合偏最小二乘回归变量投影重要性(variable importance in projection,VIP)分析、单因素方差分析(P<0.05)以及计算气味活性值(odor activity value,OAV)确定关键香气组分。共鉴定出99种香气组分,包括醇类、醛类、酮类、酯类、萜烯类、烷烃类和酸类。PCA和PLS-DA表明,产区对修水宁红茶的香气组分具有显著影响。结合VIP分析,共筛选出22种VIP值大于1的香气组分,通过方差分析进一步筛选出8种香气组分,确定了(E)-3-己烯-1-醇、(E)-呋喃芳樟醇氧化物、δ-杜松烯、正己醛、(Z)-3-己烯己酸酯和苯甲醇是修水宁红茶的关键呈香物质。该研究揭示了产区对修水宁红茶香气组分的显著影响,确定了关键呈香物质,明确了其对感官品质的贡献,为修水宁红茶的香味调控和品质提升提供了科学依据和研究基础。展开更多
文摘2,4,6-trichlorophenol molecularly imprinted suspension polymer has been prepared and applied to the molecularly imprinted micro-solid-phase extraction procedure for selective preconcentration of phenolic compounds from environmental water samples. The influence of functional monomer, cross-linker, polymerization condition, porogen, and the ratio of template molecule and functional monomer to cross-linker on the size of the obtained particles were investigated. It was found that methyacrylic acid as functional monomer, divinylbenzene as cross-linker, the molar ratio of template molecule and functional monomer to cross-linker was 1:4:20, the amount of AIBN was 100 mg, ultraviolet radiation at 365 nm were the optimal conditions, and at these conditions, the polymers had the best adsorption efficiency and had the monodispersity of 2 - 3 μm microsphere particles. The characteristics of the MIMSPE method were valid by high performance liquid chromatography. This MIMSPE-HPLC method has been successfully applied to the direct preconcentration and determination of phenolic compounds (phenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol) in environmental water samples.
文摘该研究旨在分析不同产区修水宁红茶的香气组分及感官品质差异,探讨产区对其品质的影响。采用顶空固相微萃取-气相色谱-质谱联用技术(headspace solid-phase microextraction and gas chromatography mass spectrometry,HS-SPME-GC-MS)分析3个产区的修水宁红茶香气组分,并运用主成分分析(principal component analysis,PCA)和偏最小二乘判别分析(partial least squares discrimination analysis,PLS-DA)评估产区对香气组分的影响,结合偏最小二乘回归变量投影重要性(variable importance in projection,VIP)分析、单因素方差分析(P<0.05)以及计算气味活性值(odor activity value,OAV)确定关键香气组分。共鉴定出99种香气组分,包括醇类、醛类、酮类、酯类、萜烯类、烷烃类和酸类。PCA和PLS-DA表明,产区对修水宁红茶的香气组分具有显著影响。结合VIP分析,共筛选出22种VIP值大于1的香气组分,通过方差分析进一步筛选出8种香气组分,确定了(E)-3-己烯-1-醇、(E)-呋喃芳樟醇氧化物、δ-杜松烯、正己醛、(Z)-3-己烯己酸酯和苯甲醇是修水宁红茶的关键呈香物质。该研究揭示了产区对修水宁红茶香气组分的显著影响,确定了关键呈香物质,明确了其对感官品质的贡献,为修水宁红茶的香味调控和品质提升提供了科学依据和研究基础。
