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1.
目的 采用气相色谱法-质谱法对牛奶中有机磷农药残留的不确定度进行评估。方法 通过气质联用法对测定牛奶中有机磷农药残留量测定过程进行分析,应用数学模型计算出测定过程中的不确定度,最后计算出相对合成标准不确定度和扩展不确定度。结果 当牛奶中敌敌畏含量为0.507 mg/kg时,其扩展不确定度为7.35×10-3 mg/kg(k=2);当牛奶中甲拌磷含量为0.509 mg/kg时,其扩展不确定度为5.45×10-3 mg/kg(k=2);当牛奶中乐果含量为0.450 mg/kg时,其扩展不确定度为6.35×10-3 mg/kg (k=2);当牛奶中毒死蜱含量为0.459 mg/kg时,其扩展不确定度为6.09×10-3 mg/kg (k=2);当牛奶中对硫磷含量为0.435 mg/kg时,其扩展不确定度为6.53×10-3 mg/kg (k=2)。结论 影响测量结果不确定度的主要来源为测量重复性和方法的准确度,其他因素的影响相对较小。  相似文献   

2.
评定气相色谱法测定蜂蜜中马拉硫磷残留量的不确定度。方法 参照JJF 1059.1-2012《测量不确定度评定与表示》和JJF1135-2005《化学分析测量不确定度评定》, 建立气相色谱法测定蜂蜜中马拉硫磷残留量的不确定度的数学模型, 对测量过程中各测量不确定度分量进行分析和计算。结果 通过对各测量不确定度分量的计算和合成,蜂蜜样品中马拉硫磷的残留量为0.021 mg/kg, 扩展不确定度为0.0037 mg/kg(k=2)。结论 气相色谱法测定蜂蜜中马拉硫磷残留量的不确定度主要来源为标准曲线的拟合, 其次是样品测量重复性和标准溶液, 而回收率与样品前处理影响较小。  相似文献   

3.
目的采用气相色谱法-质谱法对牛奶中有机磷农药残留的不确定度进行评估。方法通过气质联用法对测定牛奶中有机磷农药残留量测定过程进行分析,应用数学模型计算出测定过程中的不确定度,最后计算出相对合成标准不确定度和扩展不确定度。结果当牛奶中敌敌畏含量为0.507 mg/kg时,其扩展不确定度为7.35×10-3 mg/kg(k=2);当牛奶中甲拌磷含量为0.509 mg/kg时,其扩展不确定度为5.45×10-3 mg/kg(k=2);当牛奶中乐果含量为0.450 mg/kg时,其扩展不确定度为6.35×10-3 mg/kg(k=2);当牛奶中毒死蜱含量为0.459mg/kg时,其扩展不确定度为6.09×10-3 mg/kg(k=2);当牛奶中对硫磷含量为0.435 mg/kg时,其扩展不确定度为6.53×10-3 mg/kg(k=2)。结论影响测量结果不确定度的主要来源为标准溶液配制的准确性、测量重复性和方法的准确度,其他因素的影响相对较小。  相似文献   

4.
对气相色谱法测定茶叶中杀螟硫磷残留量的不确定度进行评估,从各检测步骤分析该方法不确定度来源。计算出茶叶中杀螟硫磷为0.5365mg/kg时,其扩展不确定度为0.0131 mg/kg(扩展因子k=2)。研究结果表明,茶叶中杀螟硫磷农药残留量测定的测量不确定度主要来源于色谱峰面积测定。  相似文献   

5.
目的 评定气相色谱法测定鲜枸杞中氧乐果含量的不确定度。方法 参考JJF 1059.1-2012《测量不确定度评定与表示》,应用国家农业行业标准NY/T 761-2008《蔬菜和水果中有机磷、有机氯、拟除虫菊酯和氨基甲酸酯类农药多残留的测定》对鲜枸杞中氧乐果农药残留进行检测,并对其测定过程的不确定度进行了评定和分析。结果 在鲜枸杞中的氧乐果含量测定中,当样品的氧乐果含量为0.045 mg/kg时,其扩展不确定度为0.006 mg/kg(k=2),结果表示为(0.045±0.006)mg/kg。结论 鲜枸杞中氧乐果农药残留测量结果的主要不确定度来自样品重复测量,标准溶液配制,样品前处理、定容,标准溶液重复测定,样品称量5个因素,其中样品重复测量引入的相对标准不确定度分量贡献最大,而由样品称量引入的相对标准不确定度分量最小。  相似文献   

6.
建立气相色谱法测定茶叶中毒死蜱残留的不确定度评定数学模型,全面考虑测量过程中的不确定度来源,分别用最小二乘法对标准曲线拟合的不确定度,以及极差法对测定次数较少的不确定度进行评定。茶叶中毒死蜱残留的评定结果为(0.1777±0.0288)mg/kg,k=2。  相似文献   

7.
采用气相色谱外标法对茶鲜叶中敌敌畏、乐果、马拉硫磷和杀螟硫磷4种农药残留量进行测定,依据不确定度评定的相关标准及规范,建立不确定度评定的数学模型,对整个检测过程中不确定度进行系统性评价,包括样品测定重复性、标准曲线拟合、添加回收率3个A类评定分量,以及标准溶液配制、样品称量和前处理、仪器测定4个B类评定分量。结果显示:当茶鲜叶中敌敌畏、乐果、马拉硫磷、杀螟硫磷的残留量分别为0.096、0.39、0.19、0.19 mg/kg时,其扩展不确定度分别为0.021、0.073、0.036、0.023 mg/kg(k=2,置信概率P=95%)。标准溶液配制及标准曲线拟合是引入不确定度的主要因素,在今后的检测过程中应加以重点关注。该评定结果为客观评价茶鲜叶中4种有机磷农药残留检测结果的准确性提供了参考。  相似文献   

8.
目的:评定气相色谱法测定蔬菜中有机磷农药残留量的测量不确定度,为客观分析蔬菜中多组分农药残留检测结果的可靠性提供参考。方法:以NY/T 761-2008第一部分方法二的标准方法为研究对象,分析有机磷农药残留量测定的全过程,从标准溶液、样品制备、重复性、标准曲线拟合和回收率等五个方面对检测方法的测量不确定度进行了评定,确认不确定度的来源和大小,合成标准不确定度,计算扩展不确定度并报出结果。结果:蔬菜中16种有机磷农药的含量范围为0.100~0.339 mg/kg,扩展不确定度范围在0.016~0.052 mg/kg之间(P=95%,k=2)。结论:气相色谱法测定蔬菜中有机磷农药残留量的测量不确定度主要来源为标准曲线拟合,其次为回收率,可通过选择合适的标准溶液浓度制作标准曲线、优化前处理方法、质控样品等措施减少不确定度,保证检测结果的准确、可靠。  相似文献   

9.
目的对QuEChERS-气相色谱-串联质谱法测定结球甘蓝中甲基毒死蜱农药残留进行不确定度评估。方法运用气相色谱-串联质谱法对结球甘蓝中甲基毒死蜱残留量进行测定,通过建立数学模型,分析测定过程的主要不确定度来源,对各个分量进行评估。结果不确定性的主要来源是标准溶液的配制、工作曲线的拟合及加标回收率引入。当甲基毒死蜱的残留量为0.041 mg/kg时,扩展不确定度为0.003 mg/kg (k=2)。结论该方法适用于气相色谱-串联质谱法测定甲基毒死蜱残留量的不确定度分析,可为农药残留测量结果的准确性提供科学可靠的依据。  相似文献   

10.
目的:建立一种固相萃取-气相色谱法检测甘蓝蔬菜中的马拉硫磷、氧乐果和治螟磷残留的分析方法。方法:用乙腈进行提取甘蓝样品,固相萃取柱净化,气相色谱火焰光度检测器(FPD)进行定性定量分析。结果:马拉硫磷、氧乐果和治螟磷在0.02~2.0μg/mL浓度范围内线性良好,相关系数(r2)均大于0.995。3种有机磷农药在低、中、高不同浓度的加标回收率均在81.2~100.6%。检出限如下:马拉硫磷:0.013mg/kg,氧乐果:0.010mg/kg,治螟磷:0.005mg/kg。精密度测试结果的相对标准偏差均在1.96~4.21%之间。结论:该方法操作简单,精密度高、准确度好,适用于甘蓝中多种有机磷农药残留的分析测定。  相似文献   

11.
本试验研究了大米粉中3种有机磷农药含量测量审核方法,采用气相色谱-质谱/质谱法对大米粉中马拉硫磷、毒死蜱、对硫磷进行测量审核,并通过加标质量控制措施对测定结果进行评价。结果表明:大米粉中马拉硫磷、毒死蜱、对硫磷测定结果分别为0.652 mg/kg、0.673 mg/kg、0.282 mg/kg,Z值分别为-0.80、-0.16、-0.51,该方法定量定性测定能力较好。  相似文献   

12.
This article examines the fate of four pesticides that can be present during the brewing of lager beer. For this purpose, malted barley was spiked at 2 mg/kg with pendimethalin and trifluralin (dinitroaniline herbicides) and fenitrothion and malathion (organophosphorus insecticides). Analyses of pesticide residues were carried out by a gas chromatograph with an electron capture detector, and their identity was confirmed by gas chromatography-mass spectrometry. Cleanup was necessary for the malt and spent grain samples. Beginning with mashing and ending with the final product 4 months later, various samples (spent grain, sweet wort, brewer wort, and beer) were taken to determine the concentration of the targeted residual pesticides during the various beer making phases. In all cases, the residual levels recorded in sweet wort sampled after the mashing phase were below the respective maximum residue limits established by Spanish legislation for barley. Significant proportions of pesticide residues (17 to 40%) were retained on the spent grain. Applying the standard first-order kinetics equation (r > 0.91), the half-lives obtained for the four compounds during the storage of the spent grain (3.5 months) varied from 138 days (fenitrothion) to 192 days (malathion and pendimethalin). Herbicide residues practically disappeared (<0.3%) after wort boiling, whereas the percentages of the remaining insecticides, fenitrothion and malathion, ranged from 3.5 to 4.3%, respectively, at this time. No residues of dinitroaniline compounds were detected in young beer, whereas there was a significant reduction in fenitrothion (58%) and malathion (71%) residues during fermentation. Lagering and filtering processes also reduced the content of the organophosphorus insecticides (33 to 37%). Finally, after the storage period (3 months), the content of fenitrothion was reduced by 75%, with malathion residues being below its detection limit.  相似文献   

13.
The aim of this study was to investigate the organophosphorus (OP) pesticide residues in market foods (cereals, vegetables, and fruits) in the Shaanxi area of China. The concentrations of eight OP pesticides were determined by gas chromatography with flame photometric detection (GC-FPD). In 18 of 200 samples, five OP pesticides, including dichlorvos, dimethoate, parathion-methyl, pirimiphos-methyl and parathion, were found in concentrations ranging from 0.004 to 0.257 mg/kg. The mean levels of dimethoate in fruits and parathion in vegetables exceeded the maximum residue limits (MRLs) allowed by the Ministry of Health, of China. Other detectable OP pesticide residues levels were below their MRLs. Demeton, diazinon and sumithion were not found in any sample. The results provide important information on the current contamination status of a key agricultural area in China, and point to the need for urgent action to control the use of some excessively applied and potentially persistent OP pesticides, such as dimethoate and parathion.  相似文献   

14.
建立了气相色谱同时测定小麦胚片中敌敌畏、灭线磷、硫线磷等26种有机磷农药残留量的方法,并通过考察基质效应比较了两种不同前处理方式对测定结果的影响。通过选用DB-17型毛细管色谱柱和程序升温实现目标物的分离,采用火焰光度检测器进行定量测定。结果表明,26种有机磷农药在0.010~1.0 μg/mL的浓度范围内与其对应的峰面积呈线性关系,线性相关系数均大于0.999,方法定量限在0.005~0.010 mg/kg之间。对样品进行三个水平的加标回收试验,结果表明,加标回收率在80.61%~116.19%之间,测定结果的相对标准偏差在0.62%~6.83%之间,该方法可应用于小麦胚片中26种有机磷农药的定性筛查和定量测定,在实际样品测定中筛查出马拉硫磷、甲基毒死蜱和杀螟硫磷,含量分别为0.074±0.005、0.062±0.004、0.043±0.002 mg/kg。  相似文献   

15.
目的研究对硫磷、甲基对硫磷和乐果对微酸性电解水的敏感性,检测其降解产物并推断降解过程。方法以对硫磷、甲基对硫磷和乐果标准品单一组分为研究对象,通过调节反应时间、微酸性电解水有效氯浓度和有机磷农药的初始浓度,采用气相色谱-质谱联用法检测有机磷农药的降解产物。对有机磷农药在微酸性电解水主要活性成分次氯酸和羟自由基作用下的降解途径进行了分析。结果在反应时间30 s下,有效氯浓度为5.66 mg/L时,对硫磷、甲基对硫磷和乐果的降解率均能达到100%。并检测到对硫磷和甲基对硫磷的直接降解产物对氧磷和甲基对氧磷。结论微酸性电解水能够有效降解有机磷农药,并对HOCl和·OH共同作用于有机磷农药这一降解途径做出假设。该研究对于电解水在消除果蔬有机磷农药残留的应用具有一定的理论意义。  相似文献   

16.
This paper describes the use of a fully automated on‐line reversed‐phase liquid chromatography–gas chromatography (RPLC‐GC) method for the determination of four organophosphorus pesticides (dimethoate, methidathion, chlorpyriphos and fenitrothion) in olive oil. These pesticides are among those more extensively used to control pests and disease in olive trees. Various treatments with these pesticides, at various doses and stages of olive ripening, were carried out in an olive grove. The olives were harvested in mid‐December and immediately processed into oil in the laboratory. Fully automated analyses by on‐line RPLC‐GC using the through oven transfer adsorption desorption (TOTAD) interface was carried out without any kind of sample pretreatment other than a simple filtration step. A statistical analysis was performed. No dimethoate remained in the oil owing to the high solubility of dimethoate in water. Differences between the other three pesticide residues were significant. Chlorpyriphos provided the lowest residues, followed by fenitrothion and methidathion. Treatments carried out in June did not leave residues in the oil, but all the treatments carried out in October and December led to pesticide residues that were higher than the limits of detection. Copyright © 2005 Society of Chemical Industry  相似文献   

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