目的建立气相色谱-三重四级杆质谱法(gas chromatography-triple quadruple mass spectrometry,GC-MS/MS)测定人参中22种有机氯农残的分析方法。方法参考《中华人民共和国药典》2015年版,选择样品前处理方法,优化色谱质谱条件,建立22种...目的建立气相色谱-三重四级杆质谱法(gas chromatography-triple quadruple mass spectrometry,GC-MS/MS)测定人参中22种有机氯农残的分析方法。方法参考《中华人民共和国药典》2015年版,选择样品前处理方法,优化色谱质谱条件,建立22种有机氯农残的GC-MS/MS检测方法。结果22种有机氯农药在2.5~1000μg/L范围内,线性关系良好,线性相关系数(r^2)为0.9992~0.9999;加标回收率良好为81.40%~118.29%,相对标准偏差(relative standard deviation,RSD)值为9.25%;重复性良好,RSD值为1.46%~3.28%;检出限为0.01~2.57μg/kg,定量限为0.03~8.63μg/kg。结论该方法能满足中国药典的检测要求,检测结果通过了中国食品药品检定研究院开展的人参中22种有机氯农残能力验证项目,表明本实验室具备该项目的检测能力,对人参及其它中药材中有机氯农残的监控,保障人们的安全食用和身体健康具有积极意义。展开更多
Ephemeral gullies,which are widely developed worldwide and threaten farmlands,have aroused a growing concern.Identifying and mapping gullies are generally considered prerequisites of gully erosion assessment.However,e...Ephemeral gullies,which are widely developed worldwide and threaten farmlands,have aroused a growing concern.Identifying and mapping gullies are generally considered prerequisites of gully erosion assessment.However,ephemeral gully mapping remains a challenge.In this study,we proposed a flow-directional detection for identifying ephemeral gullies from high-resolution images and digital elevation models(DEMs).Ephemeral gullies exhibit clear linear features in high-resolution images.An edge detection operator was initially used to identify linear features from high-resolution images.Then,according to gully erosion mechanism,the flow-directional detection was designed.Edge images obtained from edge detection and flow directions obtained from DEMs were used to implement the flow-directional detection that detects ephemeral gullies along the flow direction.Results from ten study areas in the Loess Plateau of China showed that ranges of precision,recall,and Fmeasure are 6 o.66%-90.47%,65.74%-94.98%,and63.10%-91.93%,respectively.The proposed method is flexible and can be used with various images and DEMs.However,analysis of the effect of DEM resolution and accuracy showed that DEM resolution only demonstrates a minor effect on the detection results.Conversely,DEM accuracy influences the detection result and is more important than the DEM resolution.The worse the vertical accuracy of DEM,the lower the performance of the flow-directional detection will be.This work is beneficial to research related to monitoring gully erosion and assessing soil loss.展开更多
文摘目的建立气相色谱-三重四级杆质谱法(gas chromatography-triple quadruple mass spectrometry,GC-MS/MS)测定人参中22种有机氯农残的分析方法。方法参考《中华人民共和国药典》2015年版,选择样品前处理方法,优化色谱质谱条件,建立22种有机氯农残的GC-MS/MS检测方法。结果22种有机氯农药在2.5~1000μg/L范围内,线性关系良好,线性相关系数(r^2)为0.9992~0.9999;加标回收率良好为81.40%~118.29%,相对标准偏差(relative standard deviation,RSD)值为9.25%;重复性良好,RSD值为1.46%~3.28%;检出限为0.01~2.57μg/kg,定量限为0.03~8.63μg/kg。结论该方法能满足中国药典的检测要求,检测结果通过了中国食品药品检定研究院开展的人参中22种有机氯农残能力验证项目,表明本实验室具备该项目的检测能力,对人参及其它中药材中有机氯农残的监控,保障人们的安全食用和身体健康具有积极意义。
基金funded by the National Natural Science Foundation of China (Grant No. 41930102, 41971333, 41771415, and 41701449)the Priority Academic Program Development of Jiangsu Higher Education Institutions (Grant No. 164320H116)the Open Fund of Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution (Grant No. KLSPWSEPA04)。
文摘Ephemeral gullies,which are widely developed worldwide and threaten farmlands,have aroused a growing concern.Identifying and mapping gullies are generally considered prerequisites of gully erosion assessment.However,ephemeral gully mapping remains a challenge.In this study,we proposed a flow-directional detection for identifying ephemeral gullies from high-resolution images and digital elevation models(DEMs).Ephemeral gullies exhibit clear linear features in high-resolution images.An edge detection operator was initially used to identify linear features from high-resolution images.Then,according to gully erosion mechanism,the flow-directional detection was designed.Edge images obtained from edge detection and flow directions obtained from DEMs were used to implement the flow-directional detection that detects ephemeral gullies along the flow direction.Results from ten study areas in the Loess Plateau of China showed that ranges of precision,recall,and Fmeasure are 6 o.66%-90.47%,65.74%-94.98%,and63.10%-91.93%,respectively.The proposed method is flexible and can be used with various images and DEMs.However,analysis of the effect of DEM resolution and accuracy showed that DEM resolution only demonstrates a minor effect on the detection results.Conversely,DEM accuracy influences the detection result and is more important than the DEM resolution.The worse the vertical accuracy of DEM,the lower the performance of the flow-directional detection will be.This work is beneficial to research related to monitoring gully erosion and assessing soil loss.
