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自行设计并制作了一种在线自动还原装置用于将尿样中可能存在的无机砷从砷(Ⅴ)还原砷(Ⅲ)。为使砷(Ⅴ)还原至砷(Ⅲ),将尿样4.8mL与1.2mL混合还原剂(每升溶液中含硫脲100g及抗坏血酸50g)混合后在反应器中于70℃加热2min。分取此溶液1.5mL与20g.L-1硼氢化钾溶液(溶于5g.L-1氢氧化钠溶液中)2.0mL,在氢化物发生器中反应生成AsH3,然后由载气(氩气)带至原子化器中,并进行原子荧光检测,所制的在线还原器及测定砷的方法已应用于儿童尿样中无机砷的测定,并在这些样品的基础上用标准加入法做回收试验,测得回收率在90.2%~102.6%之间。 相似文献
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建立了测定粗锌中砷含量的原子荧光光谱法。粗锌样品经硝酸溶液(1+1)低温溶解完全以后,在盐酸介质中,用抗坏血酸预还原,以硫脲掩蔽铜、铁、银等杂质元素,砷被硼氢化钾还原为氢化物,用氩气导入原子化器测量。砷测定结果的相对标准偏差为1.5%~3.0%(n=11),加标回收率为98.4%~103.6%。与国家标准测定方法分光光度法测定结果对比,相对偏差为0.1%~2.4%。该法准确、可靠,适用于砷含量在0.005 0%~0.50%之间的粗锌中砷的测定。 相似文献
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无火焰原子化-原子吸收光谱法测定不锈钢中砷量 总被引:1,自引:0,他引:1
在火焰原子吸收分光光度计火焰上方放置一只特制的不锈钢管作为原子化器,将不锈钢样品溶液定量滴加在不锈钢原子化管内,在乙炔-一氧化二氮高温火焰下对不锈钢样品中微量砷的含量进行无火焰原子化测定,以标准加入法进行定量分析.方法的特征质量为59 pg/1%,绝对检出限(3σ)为3.6 pg. 相似文献
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氢化物发生-原子吸收光谱法快速测定锌电解料液中痕量砷 总被引:2,自引:0,他引:2
在盐酸介质中,As(Ⅴ)用碘化钾和抗坏血酸还原成As(Ⅲ)后,再与强还原剂硼氢化钾反应生成气态氢化砷。氢化砷用氮载气送入原子化系统原子化后进行测定,砷的最大吸了波长为193.7nm,在0.5-50ng.ml^-1范围内,砷浓度与吸光度呈线性关系,检出限为3.4*10^9mol.L^-1。方法毋需预处理直接用于锌电解料液中微量和痕量砷的测定,结果满意。 相似文献
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建立氢化物发生-原子荧光光谱法(HG-AFS)测定铀钼矿钼反萃取液、净化液中砷含量的分析方法。仪器主要工作条件:负高压280 V,灯电流60 mA,原子化器高度9 mm,载气流量400 mL/min,屏蔽气流量1000 mL/min。砷的质量浓度在0~40μg/L范围内与荧光强度呈良好的线性,线性相关系数r=0.9998。方法测定砷的检出限为0.037μg/L,测定结果的相对标准偏差小于5%(n=6),加标回收率为90.5%~102.5%。针对溶液中的钼同多酸和杂多酸以及存在的其它氧化物,采取抗坏血酸-硫脲混合溶液进行预还原,溶液中铀含量约为0.1 g/L时,对砷的测定无影响。该法能满足铀钼矿钼反萃取液、净化液中砷含量0.005~4 g/L的测定要求。 相似文献
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石墨炉原子吸收法测定中药中的微量砷 总被引:12,自引:0,他引:12
以硝酸镍作基体改进剂,研究了砷的最佳灰化温度和原子化温度,建立了用石墨护原子吸收法直接测定中药中砷含量的方法。结果表明,砷含量在0~400×10-9范围内与吸光度呈良好的线性关系(γ=0.9993),对鱼腥草平行测定了6次,相对标准偏差为4.2%,样品中常共存的9种阳离子及酸在实验条件下不干扰测定,回收率在93%~97%之间,结果令人满意。 相似文献
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流动注射——氢化物原子吸收法测定食品级碳酸钙中砷 总被引:3,自引:0,他引:3
张衍林 《理化检验(化学分册)》1997,(6)
用盐酸溶解碳酸钙试样,碘化钾-抗坏血酸预还原,硼氢化钠作还原剂,流动注射法发生砷化氢,并用氮气载入电热石英原子化器中进行原子化,在240·h的采样频率下,砷的特征浓度为0.2ng·ml~(-1),检出限(3σ)为0.6ng·ml~(-1),回收率为96.4%,相对标准偏差为3.3%. 相似文献
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利用手持技术改进测定乙醇分子结构实验 总被引:1,自引:0,他引:1
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1989,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988. 相似文献
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Mustafa R. Ibrahim Zacharia A. Fataftah Paul von Ragu Schleyer Peter D. Stout 《Journal of computational chemistry》1987,8(8):1131-1138
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases. 相似文献
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由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1988,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae. 相似文献
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The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted
indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator
model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was
established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing
analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997. 相似文献