Many kinds of pesticides have been developed and used to yield a good harvest but the residues in agricul-tural products cause health problems. It is important to keep watch on these residues by using adequate methods...Many kinds of pesticides have been developed and used to yield a good harvest but the residues in agricul-tural products cause health problems. It is important to keep watch on these residues by using adequate methods of analysis. Pretreatment such as gel permeation chromatography (GPC) or column chromatography is often needed for the quantitative analysis of pesticide in agricultural products by conventional methods such as gas chromatography/low resolving power mass spectrometry (GC/LRMS). However, these pretreat-ments need a lot of work and take time. New methods saving the necessity of these pretreatments have been desired. We have applied selected reaction monitoring (SRM) to quantitatively determine cypermethrin residues in Perilla frutescens samples and compared the results with LRMS and HRMS in SIM mode. A background peak caused by the matrix overlapped the cypermethrin peak in the analysis using LRMS. SRM and HRMS in SIM mode provided chromatograms without matrix interference. The high selectivity of the product ion (m/z 127) produced from precursor ion (m/z 163) isolated the target peaks from the matrix peaks when using SRM. This method eliminates the pretreatment step, thus saving time and simplify ing the ana-lytical process.展开更多
A new method was developed for the simultaneous analysis of 12 pesticide residues in onion and fennel by gas chromatography(GC)-triple quadrupole mass spectrometry(MS/MS)-electron impact ion source(EI)-select reaction...A new method was developed for the simultaneous analysis of 12 pesticide residues in onion and fennel by gas chromatography(GC)-triple quadrupole mass spectrometry(MS/MS)-electron impact ion source(EI)-select reaction monitoring mode(SRM).The 12 pesticide includes fungicide,acaricide,carbamate and plant growth regulator pesticide.The complicated matrix samples of onion and fennel were extracted by acetonitrile,cleaned up by solid phase extraction of Carb/PSA.By optimizing the GC-MS/MS-SRM parameters,the interference from clean-up procedure was further removed and 12 pesticide residues were determined accurately.The average recoveries for most pesticides(at the spiked level of 0.05-0.20 mg/kg) were between 114%-156%,the relative standard deviation(RSD) of the method was less than 20%,and the limit of detection were 0.5-5 μg/kg.展开更多
运用气相色谱-离子阱质谱（ion trap mass spectrometry，ITMS）建立了大气中8种多溴二苯醚的二级质谱（MS／MS）检测方法。优化后的MS／MS方法对7种三溴至七溴二苯醚（BDE28、-47、-99、-100、-153、-154、-183）和十溴二苯醚（BDE209...运用气相色谱-离子阱质谱（ion trap mass spectrometry，ITMS）建立了大气中8种多溴二苯醚的二级质谱（MS／MS）检测方法。优化后的MS／MS方法对7种三溴至七溴二苯醚（BDE28、-47、-99、-100、-153、-154、-183）和十溴二苯醚（BDE209）的仪器检出限分别为0．04～0．23pg和9．38pg；方法检出限为6．0～27．1pg／m^3和211．6pg／m^3；6点标准曲线相关系数（r）为0．9980～0．9999。方法对8种目标物的加标回收率为79．1％～101．0％，相对标准偏差（RSD）为4．3％～14．3％（n=6）。对6份南京实际大气样品的检测结果表明：离子阱质谱的选择反应监测（selected reaction monitoring，SRM）技术能有效的降低背景干扰。优化后的MS／MS方法对目标化合物有较高的灵敏度，可应用于大气中痕量多溴二苯醚的定量检测。展开更多
Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent,circulative manner by homopteran insects.Using fluorescence 2-D difference gel electrophoresis to ...Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent,circulative manner by homopteran insects.Using fluorescence 2-D difference gel electrophoresis to compare the proteomes of F2 genotypes of Schizaphis graminum segregating for virus transmission ability,we recently discovered a panel of protein biomarkers that predict vector competency.Here we used aphid and whitefly nucleotide and expressed sequence tag database mining to test whether these biomarkers are conserved in other homopteran insects.S.graminum gene homologs that shared a high degree of predicted amino acid identity were discovered in two other aphid species and in the whitefly Bemisia tabaci.Selected reaction monitoring mass spectrometry was used to validate the expression of these biomarkers proteins in multiple aphid vector species.The conservation of these proteins in multiple insect taxa that transmit plant viruses along the circulative transmission pathway creates the opportunity to use these biomarkers to rapidly identify insect populations that are the most efficient vectors and allow them to be targeted for control prior to the spread of virus within a crop.展开更多
文摘Many kinds of pesticides have been developed and used to yield a good harvest but the residues in agricul-tural products cause health problems. It is important to keep watch on these residues by using adequate methods of analysis. Pretreatment such as gel permeation chromatography (GPC) or column chromatography is often needed for the quantitative analysis of pesticide in agricultural products by conventional methods such as gas chromatography/low resolving power mass spectrometry (GC/LRMS). However, these pretreat-ments need a lot of work and take time. New methods saving the necessity of these pretreatments have been desired. We have applied selected reaction monitoring (SRM) to quantitatively determine cypermethrin residues in Perilla frutescens samples and compared the results with LRMS and HRMS in SIM mode. A background peak caused by the matrix overlapped the cypermethrin peak in the analysis using LRMS. SRM and HRMS in SIM mode provided chromatograms without matrix interference. The high selectivity of the product ion (m/z 127) produced from precursor ion (m/z 163) isolated the target peaks from the matrix peaks when using SRM. This method eliminates the pretreatment step, thus saving time and simplify ing the ana-lytical process.
文摘A new method was developed for the simultaneous analysis of 12 pesticide residues in onion and fennel by gas chromatography(GC)-triple quadrupole mass spectrometry(MS/MS)-electron impact ion source(EI)-select reaction monitoring mode(SRM).The 12 pesticide includes fungicide,acaricide,carbamate and plant growth regulator pesticide.The complicated matrix samples of onion and fennel were extracted by acetonitrile,cleaned up by solid phase extraction of Carb/PSA.By optimizing the GC-MS/MS-SRM parameters,the interference from clean-up procedure was further removed and 12 pesticide residues were determined accurately.The average recoveries for most pesticides(at the spiked level of 0.05-0.20 mg/kg) were between 114%-156%,the relative standard deviation(RSD) of the method was less than 20%,and the limit of detection were 0.5-5 μg/kg.
基金supported by NSF BREAD IOS:1109989,USDA-NRI 2007-04567,NSFDBI-0606596USDA-ARS 764 CRIS projects1907-101-16,1907-21000-024/25-00DNIH/NCRR funded Yeast Resource Center P41RR01182
文摘Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent,circulative manner by homopteran insects.Using fluorescence 2-D difference gel electrophoresis to compare the proteomes of F2 genotypes of Schizaphis graminum segregating for virus transmission ability,we recently discovered a panel of protein biomarkers that predict vector competency.Here we used aphid and whitefly nucleotide and expressed sequence tag database mining to test whether these biomarkers are conserved in other homopteran insects.S.graminum gene homologs that shared a high degree of predicted amino acid identity were discovered in two other aphid species and in the whitefly Bemisia tabaci.Selected reaction monitoring mass spectrometry was used to validate the expression of these biomarkers proteins in multiple aphid vector species.The conservation of these proteins in multiple insect taxa that transmit plant viruses along the circulative transmission pathway creates the opportunity to use these biomarkers to rapidly identify insect populations that are the most efficient vectors and allow them to be targeted for control prior to the spread of virus within a crop.
