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1.
过碘酸钾氧化鸡冠花红动力学光度法测定食品中痕量碘   总被引:16,自引:0,他引:16  
张爱梅  王术皓 《分析化学》1998,26(8):967-969
基于硫酸介质中,草酸钠作活化剂,碘催化过碘酸钾氧化鸡冠花红而使其褪色的反应,建立了测定痕量碘的新方法。方法灵敏、简便、选择性好。测定碘的线性范围为0-20μg/L;检出限为0.66μg/L。用于食品中痕量碘的测定,结果满意。  相似文献   

2.
碘酸根与碘离子反应生成游离碘使异硫氰酸荧光素的荧光猝灭,λex为487nm,λem为517nm,碘酸根含量在2-8μg/L范围内与荧光猝灭程度有良好线性关系,检测限为0.74μg/L,该法灵敏度高,操作简便,用于含碘含盐中微量碘酸根的测定,结果满意。  相似文献   

3.
阻抑甲苯胺蓝褪色指示反应动力学法测定痕量碘   总被引:15,自引:0,他引:15  
刘长久  张华 《分析化学》1998,26(2):222-225
研究了在盐酸介质中,痕量碘阻抑盐酸肼还原甲苯胺蓝褪色反应及其动力学条件,建立了高灵敏、高选择性测定痕量碘的新方法。测定线性范围为0 ̄8μg/L;检出限4.1×10^-10g/mL。方法用于食品中痕量碘的测定,均获得较为满意的结果。  相似文献   

4.
流动注射-催化分光光度法测定加碘食盐中的无机总碘   总被引:10,自引:0,他引:10  
根据碘酸根离子(或其它氧化态的碘)在酸性介质中先经亚砷酸还原成碘离子,再利用碘离子催化Ce(Ⅳ)-As(Ⅲ)反应可测定碘酸根离子(或其它氧化态碘)的原理,建立了流动注射催化分光光度法测定碘酸钾或碘化钾加碘食盐中无机总碘的新方法,该法质量浓度的线性范围为0~0.50mg/L,适合于上述两种加碘食盐100倍稀释液的测定,质量浓度的检出限为0.03mg/L(对应于固体食盐3μg/g的I)。对于0.30m  相似文献   

5.
荧光猝灭法测定痕量亚硝酸根   总被引:18,自引:0,他引:18  
苑宝玲  林清赞 《分析化学》2000,28(6):692-695
研究了用荧光猝灭法测定了亚硝酸根。本方法是基于亚硝酸根与碘化钾反应生成了单质碘,碘可以使2’,7’0二氯荧光素(DCF)发生荧光猝灭,从而间接测定亚硝酯根。亚硝酸根浓度在10 ̄120μg/L范围内,荧光强度差值与亚硝酸根浓度呈线性关系。检测限为5.6μg/L。本法简便、灵敏度较高,已用于合成样和分析纯试剂中亚硝酸根的测定。  相似文献   

6.
荧光光度法测定大气中痕量二氧化硫   总被引:6,自引:0,他引:6  
朱国辉  朱庆枝  许金钩 《分析化学》1999,27(11):1303-1305
在弱酸性介质中,碘与荧光素反应导致荧光素荧光强烈猝灭,而SO^2-3的存在可以有效地抑制这猝灭作用,使得体繁荣为光强度增强,籍此可测定痕量SO^2-3,在线性范围为25-150μg/L,检出限为8.7μg/L。该法快速,灵敏,选择性好,操作简便,用于大气中二氧化硫实际样品分析,结果令人满意。  相似文献   

7.
在pH1.8的H_2SO_4-NaAc缓冲溶液中,用单扫示波极谱法,Sb(Ⅲ)或者Sn(Ⅳ)-7-碘-8-羟基喹啉-5-磺酸-Se(Ⅳ)体系可产生灵敏的络合吸附催化波。锑、锡浓度分别在0.4~200μg/L和0.8~180μg/L范围内与峰高呈线性关系,检测限分别为0.2μg/L和0.4μg/L,并用于工业废水、地下水和天然水中痕量锑和锡的测定。同时对电活性络合物的组成、极谱波的性质和电极过程机理也作了讨论和研究。  相似文献   

8.
钒(Ⅳ)—硫胺素荧光光度法的研究与应用   总被引:1,自引:0,他引:1  
陈小明  黄灵芝 《分析化学》1999,27(12):1435-1437
利用钒(Ⅳ)作为氧化剂将硫胺素氧化成硫胺荧,建立了一种测量痕量硫胺素的荧光分光光度法,并将该方法应用于药物中硫胺素的测定。该方法测定硫胺素的线性范围为0.8~240.0μg/L;检出限为0.45μg/L;对于40.0μg/L的硫胺素测定10次,其相对标准偏差为1.5%。  相似文献   

9.
增敏荧光光谱法测定复方新诺明中的磺胺甲(口恶)唑   总被引:2,自引:0,他引:2  
提出了在溴化十六烷基三甲铵(CTAB)存在下,PH为4.0的HAc-NaAc缓冲溶液中,增敏荧光光谱法测定复方新诺明中磺胺甲恶唑(SMZ)含量的新方法。碘胺甲恶唑浓度在0.08-0.8μg/mL范围内,荧光强度与碘胺甲恶唑浓度呈良好的一性关系。方法的检出限为0.016μg/mL(6.32*10^-8mol/L)。方法已用于测定复方新诺明中磺胺甲恶唑的含量。  相似文献   

10.
用耐尔蓝和高碘酸盐催化光度法测定痕量铱(Ⅳ)   总被引:11,自引:1,他引:10  
研究了在弱酸性介质中,利用铱(Ⅳ)催化高碘酸钾氧化耐尔蓝(NB)形成桃红色产物,建立了催化光度法测定痕量铱的新方法。方法的线性范围为4.0 ̄40μg/L;检出限为4.0μg/L,对40μg/L Ir(Ⅳ)测定的RSD为2.02%。本法满意地用于某些矿石和冶金产品中铱的测定。  相似文献   

11.
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   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
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   

15.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

16.
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   

17.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

18.
The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.  相似文献   

19.
20.
设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。  相似文献   

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