主题：【原创】LC/MS/MS分析农残前处理

原文由 不黄的桔子(xxw5134) 发表:
有没有老师用LC/MS/MS分析农残的？
用LC/MS/MS分析农残有没有必要对样品进行净化？
比如蔬菜和水果中主要干扰是色素，那么色素是影响LC柱还是影响MS/MS？

作为质谱而言，尽可能干净的基底可以使本底对目标物的干扰降到最小，这样检测结果的准确性就能更高，因为LCMSMS是二级质谱在一级质谱上的再选择，这样抗干扰能力大大加强，所以有些方法里就不太注重前处理的净化，个人认为这样不是对的，如果干扰没办法除掉那是没办法的事，如果能去掉但只是为了省事而依赖仪器高灵敏度，这样不符合科学的精神。

过多的杂质不仅影响LC柱的寿命，也会使MSMS系统更容易受污染。

原文由 雾非雾(mcds) 发表:

原文由 不黄的桔子(xxw5134) 发表:
有没有老师用LC/MS/MS分析农残的？
用LC/MS/MS分析农残有没有必要对样品进行净化？
比如蔬菜和水果中主要干扰是色素，那么色素是影响LC柱还是影响MS/MS？

作为质谱而言，尽可能干净的基底可以使本底对目标物的干扰降到最小，这样检测结果的准确性就能更高，因为LCMSMS是二级质谱在一级质谱上的再选择，这样抗干扰能力大大加强，所以有些方法里就不太注重前处理的净化，个人认为这样不是对的，如果干扰没办法除掉那是没办法的事，如果能去掉但只是为了省事而依赖仪器高灵敏度，这样不符合科学的精神。

过多的杂质不仅影响LC柱的寿命，也会使MSMS系统更容易受污染。

不仅仅是为了省事，更重要的是为了减少前处理过程避免目标物的损失。

原文由 不黄的桔子(xxw5134) 发表:

不仅仅是为了省事，更重要的是为了减少前处理过程避免目标物的损失。

对于一些实在难检的农药，提取了，直接上样进仪器分析，这是没办法的事。

这里有几篇不用净化文献，只有摘要，下载不到。不知哪位老师有？

Analysis of pesticides in fruit, vegetables and cereals using methanolic extraction and detection by liquid chromatography–tandem mass spectrometry



Abstract

A multiresidue method is described for the determination of 74 pesticides commonly used in crop protection including mainly carbamate, conazole, benzimidazole and pyrimidine fungicides and insecticides. Pesticides residues are extracted from the samples with ethyl acetate. No additional clean-up steps are necessary. Analysis is performed by liquid chromatography–electrospray ionization–tandem mass spectrometry. The method has been validated for various fruits and vegetables matrices. Good sensitivity and selectivity of the method are obtained with limits of quantification of 0.01 mg/kg in almost all cases. Recoveries, RSD and accuracy values of the method fulfilled the criteria of validation commonly admitted. The method was applied very satisfactorily to routine analysis as a complement to traditional gc method. More than 2500 fruits and vegetables samples have been controlled, as a part of the pesticide monitoring program of the “Service de Protection de la Consommation” in Geneva. Quality control systems applied during the assays have demonstrated very good performances and stability with time.



Author Keywords: Pesticide; Liquid chromatography; Tandem mass spectrometry; Electrospray; Multiresidue; Food

A new multi-residue method for analysis of pesticide residues in fruit and vegetables using liquid chromatography with tandem mass spectrometric detection.

Jansson C, Pihlström T, Osterdahl BG, Markides KE.

Research and Development Department, Swedish National Food Administration, PO. Box 622, SE-751 26 Uppsala, Sweden. chja@slv.se

Abstract

A new multi-residue method for determination of pesticide residues in a wide variety of fruit and vegetables, using the National Food Administration (NFA) ethyl acetate extraction and determination by means of LC-MS/MS, is presented. The method includes pesticides normally detected by LC-UV or LC-fluorescence such as benzimidazoles, carbamates, N-methylcarbamates and organophosphorus compounds with an oxidisable sulphide group as well. After extraction with ethyl acetate, the extract is concentrated and an aliquot of the extract is evaporated to dryness and redissolved in methanol before injection on LC-MS/MS. The method has been validated for 57 different pesticides and metabolites. Representative species from different commodity groups were chosen as matrices in order to study the influence from different matrices on recoveries. The fortification levels studied were 0.01-0.5 mg kg(-1). Matrix effects were tested for all matrices by means of standard addition to blank extracts. The matrix effect, expressed as signal in solvent compared to signal in matrix, was in general found to be small. The obtained recoveries are, with a few exceptions, in the range 70-100%. The proposed method is quick and straightforward and no additional clean-up steps are needed. The method can be used for the analysis of all 57 pesticides in one single determination step at 0.01 mg kg(-1).

PMID: 14760853 [PubMed - indexed for MEDLINE]

原文由 不黄的桔子(xxw5134) 发表:
有没有老师用LC/MS/MS分析农残的？
用LC/MS/MS分析农残有没有必要对样品进行净化？
比如蔬菜和水果中主要干扰是色素，那么色素是影响LC柱还是影响MS/MS？

净化是需要的，否则离子源脏得非常快，维护得非常勤。

采取何种前处理方法应该根据采用分析仪器和目标物性质而选择的。目前主要资料上讲的前处理主要还是针对GC这一块，而LC这块比较少。

原文由 戈壁明珠(zongguitang) 发表:

原文由 不黄的桔子(xxw5134) 发表:
有没有老师用LC/MS/MS分析农残的？
用LC/MS/MS分析农残有没有必要对样品进行净化？
比如蔬菜和水果中主要干扰是色素，那么色素是影响LC柱还是影响MS/MS？

净化是需要的，否则离子源脏得非常快，维护得非常勤。

本来就要一天一维护，离子源脏不怕，怕的是毛细管脏。

从学校搞来一文献，发在这里不知算不算侵权，如果侵权，麻烦版主把他删除。

原文由 不黄的桔子(xxw5134) 发表:
这里有几篇不用净化文献，只有摘要，下载不到。不知哪位老师有？

Analysis of pesticides in fruit, vegetables and cereals using methanolic extraction and detection by liquid chromatography–tandem mass spectrometry

Abstract

A multiresidue method is described for the determination of 74 pesticides commonly used in crop protection including mainly carbamate, conazole, benzimidazole and pyrimidine fungicides and insecticides. Pesticides residues are extracted from the samples with ethyl acetate. No additional clean-up steps are necessary. Analysis is performed by liquid chromatography–electrospray ionization–tandem mass spectrometry. The method has been validated for various fruits and vegetables matrices. Good sensitivity and selectivity of the method are obtained with limits of quantification of 0.01 mg/kg in almost all cases. Recoveries, RSD and accuracy values of the method fulfilled the criteria of validation commonly admitted. The method was applied very satisfactorily to routine analysis as a complement to traditional gc method. More than 2500 fruits and vegetables samples have been controlled, as a part of the pesticide monitoring program of the “Service de Protection de la Consommation” in Geneva. Quality control systems applied during the assays have demonstrated very good performances and stability with time.

Author Keywords: Pesticide; Liquid chromatography; Tandem mass spectrometry; Electrospray; Multiresidue; Food

A new multi-residue method for analysis of pesticide residues in fruit and vegetables using liquid chromatography with tandem mass spectrometric detection.

Jansson C, Pihlström T, Osterdahl BG, Markides KE.

Research and Development Department, Swedish National Food Administration, PO. Box 622, SE-751 26 Uppsala, Sweden. chja@slv.se

Abstract

A new multi-residue method for determination of pesticide residues in a wide variety of fruit and vegetables, using the National Food Administration (NFA) ethyl acetate extraction and determination by means of LC-MS/MS, is presented. The method includes pesticides normally detected by LC-UV or LC-fluorescence such as benzimidazoles, carbamates, N-methylcarbamates and organophosphorus compounds with an oxidisable sulphide group as well. After extraction with ethyl acetate, the extract is concentrated and an aliquot of the extract is evaporated to dryness and redissolved in methanol before injection on LC-MS/MS. The method has been validated for 57 different pesticides and metabolites. Representative species from different commodity groups were chosen as matrices in order to study the influence from different matrices on recoveries. The fortification levels studied were 0.01-0.5 mg kg(-1). Matrix effects were tested for all matrices by means of standard addition to blank extracts. The matrix effect, expressed as signal in solvent compared to signal in matrix, was in general found to be small. The obtained recoveries are, with a few exceptions, in the range 70-100%. The proposed method is quick and straightforward and no additional clean-up steps are needed. The method can be used for the analysis of all 57 pesticides in one single determination step at 0.01 mg kg(-1).

PMID: 14760853 [PubMed - indexed for MEDLINE]

到文献求助版，那儿有很多找文献的高手。

原文由 不黄的桔子(xxw5134) 发表:
采取何种前处理方法应该根据采用分析仪器和目标物性质而选择的。目前主要资料上讲的前处理主要还是针对GC这一块，而LC这块比较少。

净化的原理都是一样的，实际上LC对净化的要求比GC还要高，因为GC衬管理玻璃毛能阻拦住大部分不挥发杂质，而LC全部都要从柱子里经过。