建立了固相膜萃取/气相色谱-质谱法同时测定水体中多种痕量酚类化合物的分析方法。采用固相膜萃取技术提取水中的痕量酚类化合物,对洗脱液种类、洗脱液体积、水样初始p H值和洗脱速率等萃取条件进行优化,并用DB-5MS色谱柱分离,气相色谱...建立了固相膜萃取/气相色谱-质谱法同时测定水体中多种痕量酚类化合物的分析方法。采用固相膜萃取技术提取水中的痕量酚类化合物,对洗脱液种类、洗脱液体积、水样初始p H值和洗脱速率等萃取条件进行优化,并用DB-5MS色谱柱分离,气相色谱-质谱法（GC-MS/SIM）进行定量测定。实验结果表明,在pH2.0的初始条件下,选择10 m L乙酸乙酯-二氯甲烷混合溶液（体积比1∶1）作为洗脱剂,控制洗脱速率为1 m L/min时,酚类化合物的平均回收率高达82.3%-97.1%。在1-800μg/L质量浓度范围内,酚类化合物的峰面积与对应质量浓度呈良好线性关系,相关系数（r^2）均在0.996以上,检出限均不大于0.017μg/L,相对标准偏差（RSD,n=8）为1.6%-4.3%。将方法应用于我国北江流域水样检测,结果可靠。该方法萃取时间短、灵敏度和准确度高、简单易行,满足实际水体中对痕量酚类化合物的检测要求,可显著提高水中痕量酚类化合物的分析效率。展开更多
In the traditional research of volatile compounds, some trace-level compounds could not be identified by gas chromatography-mass spectrometry. Target and post-targeted methods were applied in the investigation of trac...In the traditional research of volatile compounds, some trace-level compounds could not be identified by gas chromatography-mass spectrometry. Target and post-targeted methods were applied in the investigation of trace-level volatile compounds in fresh turf crop （Lolium perenne L.） based on gas chromatography in combination with hybrid quadrupole time-of-flight mass spectrometry. According to literatures published, a target analysis was performed by using retention index, accurate masses of characteristic ions and second-stage mass spectra （MS2 spectra）. And a series of experiments showed that low electron impact energy was beneficial to the improvement of the abundances of low abundance molecular ion peak. peak was beneficial to qualitative analysis. Totally, 60 Enhancing the abundances of low abundance molecular ion volatile compounds were identified, the great majority cornpounds of which were benzeneacetaldehyde （14.8%）, 2,5-dimethyl-pyrazine （9.6%）, and hexanal （9.3%）. Identification was complied by mass spectral search, retention index and accurate masses of characteristic ions.展开更多
The characteristics of planed defects in (Cr,Fe)7C3 in a chromium steel and two kinds of cast alloys have been delineated.Combining matrix analysis of electron diffraction pattern with calculated angle between planed ...The characteristics of planed defects in (Cr,Fe)7C3 in a chromium steel and two kinds of cast alloys have been delineated.Combining matrix analysis of electron diffraction pattern with calculated angle between planed detect traces and using compound reciprocal space composed of matrix cell and two rotative cells,the [011] and [013] planed defects in (Cr,Fe)-C3 have been determined in an all-round way.A crystallographic model for (Cr.Fe)2C3 has been proposed.展开更多
文摘建立了固相膜萃取/气相色谱-质谱法同时测定水体中多种痕量酚类化合物的分析方法。采用固相膜萃取技术提取水中的痕量酚类化合物,对洗脱液种类、洗脱液体积、水样初始p H值和洗脱速率等萃取条件进行优化,并用DB-5MS色谱柱分离,气相色谱-质谱法（GC-MS/SIM）进行定量测定。实验结果表明,在pH2.0的初始条件下,选择10 m L乙酸乙酯-二氯甲烷混合溶液（体积比1∶1）作为洗脱剂,控制洗脱速率为1 m L/min时,酚类化合物的平均回收率高达82.3%-97.1%。在1-800μg/L质量浓度范围内,酚类化合物的峰面积与对应质量浓度呈良好线性关系,相关系数（r^2）均在0.996以上,检出限均不大于0.017μg/L,相对标准偏差（RSD,n=8）为1.6%-4.3%。将方法应用于我国北江流域水样检测,结果可靠。该方法萃取时间短、灵敏度和准确度高、简单易行,满足实际水体中对痕量酚类化合物的检测要求,可显著提高水中痕量酚类化合物的分析效率。
文摘In the traditional research of volatile compounds, some trace-level compounds could not be identified by gas chromatography-mass spectrometry. Target and post-targeted methods were applied in the investigation of trace-level volatile compounds in fresh turf crop （Lolium perenne L.） based on gas chromatography in combination with hybrid quadrupole time-of-flight mass spectrometry. According to literatures published, a target analysis was performed by using retention index, accurate masses of characteristic ions and second-stage mass spectra （MS2 spectra）. And a series of experiments showed that low electron impact energy was beneficial to the improvement of the abundances of low abundance molecular ion peak. peak was beneficial to qualitative analysis. Totally, 60 Enhancing the abundances of low abundance molecular ion volatile compounds were identified, the great majority cornpounds of which were benzeneacetaldehyde （14.8%）, 2,5-dimethyl-pyrazine （9.6%）, and hexanal （9.3%）. Identification was complied by mass spectral search, retention index and accurate masses of characteristic ions.
文摘The characteristics of planed defects in (Cr,Fe)7C3 in a chromium steel and two kinds of cast alloys have been delineated.Combining matrix analysis of electron diffraction pattern with calculated angle between planed detect traces and using compound reciprocal space composed of matrix cell and two rotative cells,the [011] and [013] planed defects in (Cr,Fe)-C3 have been determined in an all-round way.A crystallographic model for (Cr.Fe)2C3 has been proposed.
