The assay of trace volatile low molecular weight(MW) compounds in human breath or in ambient atmosphere typically involves gas chromatography with flame ionization detection (FID). This paper introduced a direct assa...The assay of trace volatile low molecular weight(MW) compounds in human breath or in ambient atmosphere typically involves gas chromatography with flame ionization detection (FID). This paper introduced a direct assay which can overcome the difficulties of collection low concentration samples. In order to pre concentrate the trace low MW compounds, a small trapping column filled with absorbent must be used before thermal desorption of the collected samples onto chromatographic column(packed with Porapak Q) for separation. It has been proved that the characteristic of absorbent mainly influence the recoveries and the linear range of this method is from 0 05 ng to 5200 ng for pentane, methanol, ethanol and acetone.展开更多
Seven polycyclic aromatic hydrocarbons （PAHs） in atmospheric particulates were determinated by high performance liquid chromatography （HPLC） with fluorescence detector using direction injection and an on-line enri...Seven polycyclic aromatic hydrocarbons （PAHs） in atmospheric particulates were determinated by high performance liquid chromatography （HPLC） with fluorescence detector using direction injection and an on-line enrichment trap column. The method simplified the sample pretreatment, saved time and increased the efficiency. With the on-line trap column, PAHs were separated availably even underground injecting 1.0 ml sample with relatively high column efficiency. The recoveries of the seven PAHs were from 85% to 120% for spiked atmospheric particulate sample. The limit of detection was 15.3-39.6 ng/L （S/N=3.3）. There were good linear correlations between the peak areas and concentrations of the seven kinds of PAHs in the range of 1-50 ng/ml with the correlation coefficients over 0.9970. Furthermore, it also indicated that the method is available to determine PAHs in atmospheric particulates well.展开更多
A comprehensive two-dimensional liquid chromatographic system(2D SCX/RP)is con-structed with a 10-port-2-way valve using strong cation exchange chromatography(Hypersil SCX,100 mm×4.6 mm I.D.)followed by reversed ...A comprehensive two-dimensional liquid chromatographic system(2D SCX/RP)is con-structed with a 10-port-2-way valve using strong cation exchange chromatography(Hypersil SCX,100 mm×4.6 mm I.D.)followed by reversed phase chromatography(Hypersil BDS C18,15 mm×4.6 mm I.D.)to separate the complex peptides from globin peptic hydrolysate.After the sample was loaded on the SCX column,the phosphate buffer(pH 4.0)was used to elute the peptides.Then,elutes flowed through the interface and the peptides focused on the head of the trapping columns(Hypersil BDS C18,15 mm×4.6 mm I.D.)but salt passed into the waste.After the valve was switched,the samples were flushed with a backward flow into the RP analytical column.The peptides on the SCX were eluted with 12 discontinuous steps linearly increasing salt concentrations.The peptides enriched on the trapping column were desalted and separated by the RP columns.The resolution and the resolved peaks of the 2D SCX/RP system were greatly increased and the total peak capacity reached as high as 2280.展开更多
文摘The assay of trace volatile low molecular weight(MW) compounds in human breath or in ambient atmosphere typically involves gas chromatography with flame ionization detection (FID). This paper introduced a direct assay which can overcome the difficulties of collection low concentration samples. In order to pre concentrate the trace low MW compounds, a small trapping column filled with absorbent must be used before thermal desorption of the collected samples onto chromatographic column(packed with Porapak Q) for separation. It has been proved that the characteristic of absorbent mainly influence the recoveries and the linear range of this method is from 0 05 ng to 5200 ng for pentane, methanol, ethanol and acetone.
基金Project supported by the National Natural Science Foundation of China (No.20437020)Major Research Program of Chinese Academy of Sciences (No.KZCX3-SW-432).
文摘Seven polycyclic aromatic hydrocarbons （PAHs） in atmospheric particulates were determinated by high performance liquid chromatography （HPLC） with fluorescence detector using direction injection and an on-line enrichment trap column. The method simplified the sample pretreatment, saved time and increased the efficiency. With the on-line trap column, PAHs were separated availably even underground injecting 1.0 ml sample with relatively high column efficiency. The recoveries of the seven PAHs were from 85% to 120% for spiked atmospheric particulate sample. The limit of detection was 15.3-39.6 ng/L （S/N=3.3）. There were good linear correlations between the peak areas and concentrations of the seven kinds of PAHs in the range of 1-50 ng/ml with the correlation coefficients over 0.9970. Furthermore, it also indicated that the method is available to determine PAHs in atmospheric particulates well.
基金Financial support from the National Natural Science Foundation of China(Grant Nos.20175029 and 20375040)is gratefully acknowledged.
文摘A comprehensive two-dimensional liquid chromatographic system(2D SCX/RP)is con-structed with a 10-port-2-way valve using strong cation exchange chromatography(Hypersil SCX,100 mm×4.6 mm I.D.)followed by reversed phase chromatography(Hypersil BDS C18,15 mm×4.6 mm I.D.)to separate the complex peptides from globin peptic hydrolysate.After the sample was loaded on the SCX column,the phosphate buffer(pH 4.0)was used to elute the peptides.Then,elutes flowed through the interface and the peptides focused on the head of the trapping columns(Hypersil BDS C18,15 mm×4.6 mm I.D.)but salt passed into the waste.After the valve was switched,the samples were flushed with a backward flow into the RP analytical column.The peptides on the SCX were eluted with 12 discontinuous steps linearly increasing salt concentrations.The peptides enriched on the trapping column were desalted and separated by the RP columns.The resolution and the resolved peaks of the 2D SCX/RP system were greatly increased and the total peak capacity reached as high as 2280.
