共查询到16条相似文献,搜索用时 109 毫秒
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介绍了一种可以快速、便捷、灵敏地进行现场半定量和定量测定水体中重金属Cu2+浓度的络天青-氨基化纤维素试纸。该试纸的检出限为0.1 mg/L,在pH值为6.07.0时,检测的线性范围为0.17.0时,检测的线性范围为0.110.0 mg/L,反应时间为120 s。该方法可与微型光谱仪或Cu2+标准比色板联用,可以同时进行定量或者半定量检测。该试纸弥补了显色剂易从试纸上脱落的不足,增强了试纸的稳定性与准确性。该方法可应用于工业废水中Cu2+的测定,与原子吸收分光光度法的测定结果相比较,两者基本一致。 相似文献
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试纸法快速测定溶液中的银离子 总被引:1,自引:0,他引:1
用重金属离子含量低的定量滤纸,依次在硝酸镉、硫化钠溶液中浸渍,晾干后,用于测定溶液中Ag+。Ag+浓度在0~10g/L时,直接用色阶比较法,检出限0.29/L;Ag+含量低于0.1g/L时,可使用简单微型装置,20ml样品的检出限可达0.25mg/L。几种测定方法比较,结果一致。 相似文献
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This study demonstrated a promising method for quickly extracting tea polyphenol (TP) by microwave-assisted extraction (MAE)
technology. Some influential parameters, including MAE temperature, microwave power, concentration of extraction solvent,
MAE time and the solid/liquid ratio, were investigated. The optimum condition of MAE was obtained by dual extraction with
60% ethanol (v/v) and the solid/liquid ratio 1:12 g/mL at 80°C for 10 minutes under the microwave power 600W. The yield of
TP was 96.5% under the described condition. Compared with traditional methods, including hot reflux extraction (HRE), ultrasound-assisted
extraction (UAE) and supercritical fluid extraction (SFE), the extraction time was saved 8 times than that of HRE, and the
yield was increased by 17.5%. The extraction time at comparable levels of production was saved 2 times, and the energy consumption
was one fourth that of UAE. The extraction time was saved 5 times than that of SFE, and the yield of TP was increased by 40%.
Moreover, compared with MAE of TP studied by others, it decreased the solid/liquid ratio from 1: 20 to 1: 12 g/mL without
90-min pre-leaching time, and the yield of TP was increased by 6%–40%. 相似文献
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This study demonstrated a promising method for quickly extracting tea polyphenol (TP) by microwave-assisted extraction (MAE) technology. Some influential parameters, including MAE temperature, microwave power, concentration of extraction solvent, MAE time and the solid/liquid ratio, were investigated. The optimum condition of MAE was obtained by dual extraction with 60% ethanol (v/v) and the solid/liquid ratio 1:12 g/mL at 80°C for 10 minutes under the microwave power 600 W. The yield of TP was 96.5% under the described condition. Compared with traditional methods, including hot reflux extraction (HRE), ultrasound-assisted extraction (UAE) and supercritical fluid extraction (SFE), the extraction time was saved 8 times than that of HRE, and the yield was increased by 17.5%. The extraction time at comparable levels of production was saved 2 times, and the energy consumption was one fourth that of UAE. The extraction time was saved 5 times than that of SFE, and the yield of TP was increased by 40%. Moreover, compared with MAE of TP studied by others, it decreased the solid/liquid ratio from 1 ∶ 20 to 1 ∶ 12 g/mL without 90-min pre-leaching time, and the yield of TP was increased by 6%–40%. 相似文献
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MeiLing Zou MingLiang Du Han Zhu CongSheng Xu Ni Li YaQin Fu 《Polymer Engineering and Science》2013,53(5):1099-1108
Uniformly dispersed Ag nanoparticles (AgNPs) with diameter about 5 nm embedded in electrospun polyacrylonitrile (PAN) nanofibers were synthesized by using tea polyphenols (TP) as the reductant. The reducing ability of TP toward Ag ions was characterized by Fourier transform infrared spectroscopy and ultraviolet–visible spectra, and the results revealed that TP exhibit satisfied reducing ability in the synthesis process. Transmission electron microscopy observation showed that the synthesized spherical AgNPs with diameter about 5 nm were immobilized on the surface and in the interior of PAN nanofibers by electrospinning technology. The interactions of Ag with PAN and TP were investigated by X‐ray photoelectron spectroscopy (XPS), and the results suggested that PAN polymer and TP both served as stabilizer during the synthesis of AgNPs because of the chelating interactions of Ag with cyano groups and phenolic hydroxyls. The synthesized AgNPs in PAN nanofibers exhibit good antibacterial property and may be used for antibacterial and catalytic applications. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers 相似文献