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0.100 0g焦炭灰样品经氢氟酸-硝酸(1+3)溶液8mL消解,用火焰原子吸收光谱法测定其中钾和钠的含量。钾和钠的质量浓度分别在4mg.L-1及2mg.L-1以内与其吸光度呈线性关系,检出限(3σ)分别为12μg.L-1及6μg.L-1。方法用于分析焦炭灰标准物质,测定值与认定值相符,钾和钠的相对标准偏差(n=11)依次在2.7%~3.8%和1.3%~3.1%之间。 相似文献
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蒙益林高帅徐卉丁优仙姜海啸高晋峰 《化学分析计量》2021,30(11):50-54
建立火焰原子吸收光谱法测定变形高温合金GH4169中痕量钾、钠。称取0.5000 g样品,用8 mL混合酸(硝酸-氢氟酸-水的体积比为1∶1∶1)溶解,加入5 mL丙酮以提升灵敏度,在选定的仪器工作条件下进行测定。结果表明,钾元素采用样品标准加入法,钠元素采用镍基体匹配标准曲线法,溶液中钾、钠的质量浓度在0~500μg/L范围内与吸光强度呈良好的线性关系,相关系数分别为0.9980、0.9983,钾、钠的检出限分别为0.000098%、0.000058%。钾、钠9次重复测定结果的相对标准偏差分别为2.8%~7.0%、2.2%~7.9%,加标回收率分别为97%~110%、95%~107%。该方法满足变形合金GH4169中钾、钠含量的检测要求。 相似文献
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原子吸收法测定矿石中钠和钾已有很多报导,通常采用空气-乙炔火焰。据报导,在空气-乙炔火焰中,2μg/ml钠22%电离,5μg/ml钾30%电离。为克服这种干扰,需要加消电离剂。我们采用空气-液化石油气火焰,测定分子筛及矿石中的钠与钾。测定步骤:(1)矿石分析:于铂金坩埚中,用5~10毫升氢氟酸处理0.03~0.05克(准至0.0002 相似文献
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建立了火焰原子吸收光谱法测定高铼酸、高铼酸铵、铼粉中痕量钠的方法,对样品的预处理和测定钠的条件进行了研究。结果表明:水溶解法、硝酸溶解法或硝酸-硫酸溶解法溶解样品完全,测得钠的结果吻合;于选定条件下,钠的测定浓度在0.020 0~0.500 0μg/mL范围内线性良好;测定高铼酸、高铼酸铵和铼粉样品中0.27~0.47mg/L、0.000047%~0.00048%和0.000040%~0.00049%的钠含量,检出限、相对标准偏差(RSD,n=7)、加标回收率分别为高铼酸3×10-4μg/mL、6%~10%、98%~102%,高铼酸铵3×10-4μg/mL、8%~9%、96%~102%和铼粉3×10-4μg/mL、5%~9%、96%~103%。方法结果准确、分析快速、操作简便,应用于实际的样品分析,结果满意。 相似文献
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硫代乙酰胺键合硅胶在线选择性固相萃取火焰原子吸收测定环境样品中痕量铜 总被引:1,自引:0,他引:1
以制备的硫代乙酰胺键合硅胶为微柱填充材料,建立酸性条件(pH 1 0)下流动注射微柱选择性预富集,0.6 mol/L硫脲溶液洗脱,火焰原子吸收测定环境样品中痕量铜的方法。流动注射在线固相萃取的最佳采样流速为8.0 mL/min;最佳洗脱流速为5.0 mL/min,时间为60 s。在优化的条件下,采样体积为10和50 mL时,线性范围分别为2.0~100.0μg/L和0.5~30.0μg/L;检出限(3σ)分别为0.36和0.07μg/L;富集倍数分别为80和170;相对标准偏差分别为(n=9)3.5%和2.0%。研究了环境样品中常见阴阳离子对测定的干扰。应用于灌木枝叶样品(GBW07602)、标准模拟水样(GBW08608)样品和环境样品中铜的分离与富集,取得满意结果。 相似文献
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研究了用湿法消解啤酒样品、石墨炉原子吸收光谱(GFAAS)及火焰原子吸收光谱(FAAS)法分别测定啤酒中的痕量Pb2+和Zn2+。对仪器的工作参数进行了优化,探讨了混合酸消解体系、消解液用量,消解温度等因素的影响。结果表明,在200℃温度下,HNO3+HClO4(16+4)混酸能完全消解样品。Pb2+、Zn2+分别在0~80μg/L、0~1.50μg/mL范围内线性关系良好(线性相关系数r分别为0.9995和0.9997),其检出限分别为0.2μg/L、8.0μg/L。测定Pb2+、Zn2+的相对标准偏差(RSD)分别为1.8%和0.92%,加标回收率分别为96.5%和99.8%。该方法检出限低,精密度和准确度高,适用于啤酒样品中痕量铅、锌含量的测定。检测的9种啤酒样品中铅、锌含量范围分别为11.34~47.15μg/L、277~422μg/L,低于食品中的限量值。 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
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Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared. 相似文献
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Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position. 相似文献
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Stepkowska E. T. Perez-Rodriguez J. L. Jimenez de Haro M. C. Sayagues M. J. 《Journal of Thermal Analysis and Calorimetry》2002,69(1):187-204
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations
were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples
were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of
hematite Fe2O3. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the
best fitting experimental data.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6. 相似文献
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