目的建立通过式固相萃取-高效液相色谱法同时测定糕点中7种天然抗氧化成分和8种合成抗氧化剂的定量分析方法。方法目标物采用1%乙酸乙腈溶液提取,用通过式亲水亲油平衡(hydrophilic and oleophilic balance,HLB)固相萃取柱净化,净化液...目的建立通过式固相萃取-高效液相色谱法同时测定糕点中7种天然抗氧化成分和8种合成抗氧化剂的定量分析方法。方法目标物采用1%乙酸乙腈溶液提取,用通过式亲水亲油平衡(hydrophilic and oleophilic balance,HLB)固相萃取柱净化,净化液浓缩处理后供高效液相色谱仪分析,15种目标物以0.5%甲酸溶液-甲醇为流动相梯度洗脱,C18色谱柱分离,二极管阵列检测器280 nm处测定。结果15种抗氧化成分在1~50μg/mL范围内有良好的线性关系,表没食子酸儿茶素的检出限(limit of detection,LOD)为2 mg/kg,定量限(limit of quantification,LOQ)为5 mg/kg,其余14种化合物的LOD为0.2 mg/kg,LOQ为0.5 mg/kg;各组分的平均回收率为88.10%~94.73%,相对标准偏差(relative standard deviations,RSDs)≤5.2%。结论本方法具有快速简单、高灵敏度、重现性好等优点,对糕点中抗氧化剂含量的检测具有很好的实用价值,同时为糕点的质量安全提供了有效的技术支持。展开更多
Nanocomposite multilayer TiBN coatings were prepared on Si(100) and 9Cr18Mo substrates using TiBN composite cathode plasma immersion ion implantation and deposition technique(PIIID). Synthesis of TiBN composite cathod...Nanocomposite multilayer TiBN coatings were prepared on Si(100) and 9Cr18Mo substrates using TiBN composite cathode plasma immersion ion implantation and deposition technique(PIIID). Synthesis of TiBN composite cathodes was conducted by powder metallurgy technology and the content of hexagonal boron nitride(h-BN) was changed from 8% to 40%(mass fraction). The as-deposited coatings were characterized by energy dispersive spectrometer(EDS), grazing incidence X-ray diffraction(GIXRD), Fourier Transform Infrared Spectroscopy(FTIR) and high resolution transmission electron microcopy(HRTEM). EDS results show that the B content of the coatings was varied from 3.71% to 13.84%(molar fraction) when the composition of the h-BN in the composited cathodes was changed from 8 % to 40%(mass fraction). GIXRD results reveal that the TiBN coatings with a B content of 8% has the main diffraction peak of TiN(200),(220) and(311), and these peaks disappear when the B content is increased. FTIR analysis of the multilayer coatings showed the presence of h-BN in all coatings. TEM images reveal that all coatings have the characteristics of self-forming nanocomposite multilayers, where the nanocomposites are composed of face-centered cubic Ti N or h-BN nanocrystalline embedded in amorphous matrix. The tribological tests reveal that the Ti BN coatings exhibit a marked decrease of coefficient at room temperature(~0.25). The improved properties were found to be derived from the comprehensiveness of the self-forming multilayers structure and the h-BN solid lubrication effects in the coatings.展开更多
文摘目的建立通过式固相萃取-高效液相色谱法同时测定糕点中7种天然抗氧化成分和8种合成抗氧化剂的定量分析方法。方法目标物采用1%乙酸乙腈溶液提取,用通过式亲水亲油平衡(hydrophilic and oleophilic balance,HLB)固相萃取柱净化,净化液浓缩处理后供高效液相色谱仪分析,15种目标物以0.5%甲酸溶液-甲醇为流动相梯度洗脱,C18色谱柱分离,二极管阵列检测器280 nm处测定。结果15种抗氧化成分在1~50μg/mL范围内有良好的线性关系,表没食子酸儿茶素的检出限(limit of detection,LOD)为2 mg/kg,定量限(limit of quantification,LOQ)为5 mg/kg,其余14种化合物的LOD为0.2 mg/kg,LOQ为0.5 mg/kg;各组分的平均回收率为88.10%~94.73%,相对标准偏差(relative standard deviations,RSDs)≤5.2%。结论本方法具有快速简单、高灵敏度、重现性好等优点,对糕点中抗氧化剂含量的检测具有很好的实用价值,同时为糕点的质量安全提供了有效的技术支持。
基金Projects(21573054,21327002,51401201)supported by the National Natural Science Foundation of ChinaProject(U1537214)supported by the Joint Funds Key Project of the National Natural Science Foundation of ChinaProject(51535003)supported by the State Key Program of National Natural Science of China
文摘Nanocomposite multilayer TiBN coatings were prepared on Si(100) and 9Cr18Mo substrates using TiBN composite cathode plasma immersion ion implantation and deposition technique(PIIID). Synthesis of TiBN composite cathodes was conducted by powder metallurgy technology and the content of hexagonal boron nitride(h-BN) was changed from 8% to 40%(mass fraction). The as-deposited coatings were characterized by energy dispersive spectrometer(EDS), grazing incidence X-ray diffraction(GIXRD), Fourier Transform Infrared Spectroscopy(FTIR) and high resolution transmission electron microcopy(HRTEM). EDS results show that the B content of the coatings was varied from 3.71% to 13.84%(molar fraction) when the composition of the h-BN in the composited cathodes was changed from 8 % to 40%(mass fraction). GIXRD results reveal that the TiBN coatings with a B content of 8% has the main diffraction peak of TiN(200),(220) and(311), and these peaks disappear when the B content is increased. FTIR analysis of the multilayer coatings showed the presence of h-BN in all coatings. TEM images reveal that all coatings have the characteristics of self-forming nanocomposite multilayers, where the nanocomposites are composed of face-centered cubic Ti N or h-BN nanocrystalline embedded in amorphous matrix. The tribological tests reveal that the Ti BN coatings exhibit a marked decrease of coefficient at room temperature(~0.25). The improved properties were found to be derived from the comprehensiveness of the self-forming multilayers structure and the h-BN solid lubrication effects in the coatings.
