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《农药科学与管理》2021,(6)
分别依据标准方法 GB/T 20769-2008 《水果和蔬菜中450种农药及相关化学品残留量的测定液相色谱-串联质谱法》和GB 23200.121-2021 《食品安全国家标准植物源性食品中331种农药及其代谢物残留量的测定液相色谱-质谱联用法》,对大白菜中吡虫啉的残留量测定进行了不确定度评定。通过对两种方法测定步骤的具体分析并建立相应的数学模型,详细评定了包括标准溶液、样品称量、前处理过程、标准溶液峰面积、样品峰面积及方法精密度在内的不确定度分量,并计算出两种方法各自的合成相对标准不确定度及相对扩展不确定度。结果显示,在相同实验室条件下,在95%的置信限(k=2)内,方法GB 23200.121-2021的测量相对扩展不确定度为4.0%,小于GB/T 20769-2008的测量相对扩展不确定度5.6%;决定方法 GB 23200.121-2021不确定度大小的关键因素为标准溶液(占比64.3%);决定方法 GB/T 20769-2008不确定度大小的关键因素为标准溶液(占比33.1%)和方法精密度(占比51.7%)。 相似文献
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有机氯农药混合标准溶液配制不确定度评定 总被引:3,自引:0,他引:3
标准溶液的配制和稀释所引入的各种因素都可能影响其真实浓度,从而影响检测结果的准确性。评定其中的各种分量不确定度,为提高实验室的质量控制水平、降低分析成本和检测结果的正确性提供保证。本文以实际应用的24种有机氯农药混合标准溶液为例,采用了配制混合标准溶液过程单元操作的不确定度计算方法 (top down法),分析了在配制混合标准溶液过程中的所有影响因素,评定了所引入各种分量的不确度,合成扩展不确定度,得到了最终的扩展不确定度。最终结果显示,稀释过程中由2mL移液管所引入的不确定度贡献最大,表明选择好的移液器具和尽量精准的估读移液器具的刻度是影响标准溶液稀释最重要的因素。 相似文献
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高效液相色谱法测定苹果中多菌灵残留量的测量不确定度分析 总被引:3,自引:1,他引:2
建立了评定NY/T 1680-2009“蔬菜水果中多菌灵等4种苯并咪唑类农药残留量的测定——高效液相色谱法”中影响测量不确定度的各因素的数学模型,考察了样品前处理和液相色谱测定的各个环节,并根据所建立的数学模型计算了评定测量不确定度的各分量。采用该方法测得市售苹果中多菌灵的残留量为0.23 mg/kg。分析表明:多菌灵残留量测定的不确定度主要来源于样品溶液的平行测定、样品稀释以及萃取、净化等处理过程产生的回收率差异;此外,标准溶液的配制和检测过程以及提取处理等其他环节对其也有一定影响。经计算,在置信概率P=95%时,采用该方法测定试样中多菌灵残留的扩展不确定度为0.02 mg/kg,若不考虑多菌灵残留在样品中分布的均匀性,则苹果试样中多菌灵残留的检测结果可表示为(0.23±0.02) mg/kg(包含因子k=2)。 相似文献
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依据NY/T761—2008标准第二部分,采用气相色谱法对黄瓜中乙烯菌核利残留进行测定,分析检测过程中的各不确定度分量来源,建立了不确定度评定的数学模型,进而对各不确定分量进行合成与扩展。结果表明:黄瓜中乙烯菌核利残留测量结果的合成相对标准不确定度和扩展不确定度分别为2.78%和5.56%(k=2),其中标准溶液的稀释与定容过程、乙烯菌核利残留的提取和净化过程所产生的回收率差异、色谱峰面积测量导致的误差是测量不确定度的主要来源。本研究结果可为客观评价蔬菜中农药残留检测结果提供参考。 相似文献
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自2018年《CNAS-GL006化学分析中不确定度的评估指南》颁布后,不确定度计算方法的需求日益增强。本研究依据GB 23200.8-2016《水果和蔬菜中500种农药及相关化学品残留量的测定气相色谱-质谱法》,采用气相色谱-质谱法,结合内标定量法,对草莓中丙溴磷、亚胺硫磷、五氯硝基苯和氯氟氰菊酯的残留进行了测量不确定度的详细评定,共涉及标准品纯度、储备液配制、工作液配制、称样量和前处理过程5个B类评定分量,以及标准溶液峰面积、样品溶液峰面积和添加回收率3个A类评定分量。结果显示:在0.08 mg/kg添加水平下,丙溴磷、亚胺硫磷、五氯硝基苯和氯氟氰菊酯的测量合成相对标准不确定度依次为3.55%、3.22%、2.20%和3.66%,样品溶液峰面积和添加回收率2个A类不确定度分量对4种农药合成不确定度的贡献较高,其中丙溴磷、亚胺硫磷和氯氟氰菊酯均超过60%,五氯硝基苯超过31%。本研究中4种农药在草莓样品中的测量结果在95%的置信限(k=2)内可表示为:丙溴磷,0.085±0.006 mg/kg;亚胺硫磷,0.084±0.005 mg/kg;五氯硝基苯,0.079±0.003 mg/kg;氯氟氰菊酯,0.082±0.006 mg/kg。不确定度评定结果将最大限度地减少待测物在最大残留限量附近的残留值判定可能存在的争议。 相似文献
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The nature of a reductive system which actively degrades mexacarbate in the rat intestine and liver was investigated. The system is characterized by its stability against heat and protease treatments and its requirements for a flavin cofactor and an acidic pH for a maximum activity. As a result of purification and spectroscopic identification attempts the system responsible for the above reductive activity was identified to be flavoprotein. Under anerobic conditions such flavoproteinflavin cofactor systems degrade mexacarbate first to 4-N-desmethylmexacarbate and then to polar water-soluble metabolites. 相似文献
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T. Kapari-Isaia A. Kyriakou L. Papayiannis D. Tsaltas S. Gregoriou I. Psaltis 《Plant pathology》2008,57(2):348-353
A new laboratory technique combining shoot-tip grafting in vitro and biological indexing on indicator plants was explored for the detection of citrus exocortis and related viroids. Τhree in vitro laboratory methods were used and compared with the classical biological method. With the classical in vivo method, diagnosis is based on the expression of symptoms on indicators 11–14 weeks after inoculation. In contrast, with the first in vitro method, microindexing in vitro of citron seedlings by graft inoculation, diagnosis was possible 12 days after inoculation; with the second method, microindexing in vitro of citron cuttings by graft inoculation, 20 days after inoculation; and with the third method, microindexing in vitro of citron cuttings by injection inoculation, 40 days after inoculation. Inoculated Etrog citron plantlets grown in vitro and tested by RT-PCR showed the same viroid content as the source plants. Of the three in vitro viroid indexing methods, microindexing on cuttings by grafting was easier and more reliable than microindexing either on seedlings or on cuttings by injection. 相似文献
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A. D. Avgelis 《European journal of plant pathology / European Foundation for Plant Pathology》1986,92(4):147-152
Tomatoes grown in plastic houses in Crete have been inspected since 1980 for virus diseases. Plants with virus-like symptoms were checked by sap inoculation to test plants and the isolated viruses were identified by host reaction and serology. The most common viruses were, in order of frequency, tomato mosaic virus (ToMV), potato virus X, tomato bushy stunt virus (TBSV), potato virus Y and cucumber mosaic virus. The large use of ToMV-resistant cultivars reduces gradually the importance of ToMV while TBSV tends to become a serious problem of tomato in Crete.Samenvatting Van 1980–1984 werden op Kreta de in plasticfolie-kassen geteelde tomaten geïnventariseerd op de aanwezigheid van virussen. Verdachte plante werden door sapinoculatie op toetsplanten onderzocht. De daarbij geïsoleerde virussen werden daarna via de symptomen op de waardplanten en serologisch geïdentificeerd. In volgorde van belangrijkheid werden de volgende virussen het meest aangetroffen: tomatemozaïekvirus, aardappelvirus X, tomatedwerggroeivirus, aardappel Y virus en komkommermozaïekvirus, De laatste jaren is door de toenemende teelt van tomaterassen met resistentie tegen tomatemozaïekvirus het belang van dit virus sterk verminderd, terwijl het tomatedwerggroeivirus een steeds ernstiger probleem lijkt te worden. 相似文献
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利用祁连山老虎沟地区海拔4200m气象观测站2010年的观测资料,采用FAO Penman-Monteith公式,再利用作物系数法,对高寒草甸生长季(5月22-9月22)的蒸散发量进行估算和分析。结果发现:研究期共有124天,蒸散发总量为238.3mm,日均为1.87mm·d-1。生长初期、生长中期、生长末期的蒸散发总量依次为22.6mm,179.1mm,36.6mm,依次占研究期总量的8.4%,75.2%,15.3%。5月下旬至6月中旬,日均蒸散发量以较低水平缓慢上升;6月下旬迅速增加;6月末至7月中旬猛然回落;7月中旬至8月末,日均蒸散发量迅速上升且维持在较高水平;此后直到9月22日,缓慢减少。5-9月月蒸散发总量依次为6.6mm,46.4mm,74.5mm,77.6mm,33.1mm。 相似文献
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Solarization of soil in piles for the control of Meloidogyne incognita in olive nurseries in southern Spain 总被引:4,自引:0,他引:4
The potential of solarization to control Meloidogyne incognita in piles of soil used at olive nurseries in southern Spain was studied in 1999 and 2000. Kaolin and soil infested with free eggs and egg masses of the nematode in nylon bags were buried 20 and 40 cm deep inside conical piles of soil 80 cm high and with a base diameter of 1 m. Soil piles were solarized for 3 weeks in July and August. The effect of various periods of solarization was assessed by egg hatch bioassays in sterile water, and by infectivity to tomato plants. Maximum soil temperature at 20 cm depth in solarized piles was 47·4°C in 1999 and 48·2°C in 2000, compared with 32·9°C and 31·7°C in nonsolarized piles. Solarization reduced egg hatch by > 95% compared with nonsolarized samples, irrespective of type, burial depth and location of inocula in a soil pile. Egg hatch of egg mass-infested samples buried at 20 cm depth was higher than that of free eggs buried at the same depth. The differential effect associated with burial depth and type of inoculum was not found in solarized piles. In nonsolarized piles, hatch of free eggs from samples buried at 40 cm depth was higher than that from samples buried at 20 cm depth. Egg hatch in samples from solarized piles was lower than that from nonsolarized piles. A bioassay of tomato plants in 2000 confirmed the reduction in infectivity of free eggs buried in solarized soil piles. Under the conditions in southern Spain, solarization of 40 cm-high piles of soil for 3 weeks can therefore be used for the control of root-knot nematodes in potting soil for olive nursery production. 相似文献