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1.
侯明  张静 《分析科学学报》2004,20(6):619-621
在λex/λem=404.7/550nm,乳化剂OP存在下,荧光红-曙红Y能够发生有效能量转移,使曙红Y荧光强度大大提高;在pH6.5~7.6的KH2PO4-NaOH缓冲溶液中,Cu(Ⅱ)与曙红Y和邻菲罗啉形成配合物,使曙红Y的荧光猝灭,从而建立了测定痕量铜的荧光分析新方法。铜含量在0~250μg/L范围内与曙红Y的荧光猝灭程度呈良好的线性关系。方法的检出限为0.82μg/L;测定100μg/L铜溶液,其RSD为4.6%(n=11);样品加标回收率为102.1%~105%。本法用于人发、茶叶和大米中痕量铜的测定,结果满意。  相似文献   

2.
报道了一种新的双席夫碱荧光试剂——双—(2,4—二羟基苯乙酮)缩肼的合成;试剂在492.8nm处有一强荧光峰,当有铜离子存在时,可与试剂形成稳定的配合物而使试剂的荧光猝灭;利用此反应建立了一个荧光测定痕量铜的新方法,测定铜的线性范围为0.0~180.0μg/L,检出限0.02μg/L,方法可应用于矿泉水和水中痕量铜的测定。  相似文献   

3.
碲化镉纳米晶荧光猝灭法测定痕量铜(Ⅱ)   总被引:4,自引:0,他引:4  
陈波  曾娴  戴燕  俞英 《分析科学学报》2005,21(6):633-635
制备了水溶性的CdTe纳米晶。基于铜(Ⅱ)离子在pH=7,80的磷酸盐缓冲溶液中对该纳米晶的荧光具有较强的猝灭作用,建立了一种测定铜(Ⅱ)离子的新方法。在最佳条件下,体系的相对荧光强度(△F)与铜(Ⅱ)离子的浓度呈线性关系,线性范围为8.0~320.0μg/L,其线性回归方程为:△F=-8.18-0.14c(μg/L);检出限为3.24μg/L。本方法用于实际样品中痕量铜的测定,结果令人满意。  相似文献   

4.
合成了新型试剂3-对氟苯基-5.(2’-羧基苯偶氮)若丹宁,并经元素分析、IR确证了其结构。研究发现在pH=5.2时该试剂与痕量铋锄形成的螯合物可使试剂的荧光强度大大减弱,在λex/λem=305nm/404nm处有最大峰;其荧光猝灭值与铋的浓度在1.0-12μg/L范围内呈线性关系,检出限达0.26μ/L。建立了荧光光度法测定痕量铋的新方法。  相似文献   

5.
基于司帕沙星能够猝灭四溴荧光素的荧光且荧光猝灭程度与司帕沙星的量成正比,建立了一种测定微量司帕沙星的方法。在pH3.5的Clark—Lubs缓冲溶液中,四溴荧光素激发波长λex=485nm、发射波长λem=545nm,司帕沙星的质量浓度在0~2.0mg/L范围内符合比耳定律,方法检出限为42.7μg/L。已用于片剂及胶囊中司帕沙星的测定。6次平行测定回收率为93.8%~104.3%,相对标准偏差为1.1%~2.8%。  相似文献   

6.
三元杂多酸荧光猝灭测定食品中硼砂的研究   总被引:3,自引:0,他引:3  
研究发现,硼钼杂多酸能与罗丹明B形成缔合物,导致罗丹明B的荧光发生静态猝灭,以此建立了荧光猝灭测定痕量硼砂的新方法.在选定的实验条件下,当λex/λem=540/582 nm,硼砂浓度在2.4~108μg/L范围内时,荧光猝灭强度与硼砂含量呈良好线性关系(r=0.9982),检出限为1.42μg/L,加标回收率在91.3%~101%之间,相对标准偏差(RSD)<3.76%.该方法用于食品中痕量硼砂的测定,结果满意.  相似文献   

7.
研究了在pH5.0~6.4的HAC-NaAC缓冲介质中和CTMAB存在下,Mo(Ⅳ)对二甲氧基羟基苯基荧光酮(DMH-PF)的荧光猝灭效应,建立了荧光猝灭法测定微量Mo(Ⅳ)的新体系,DMH-PF最大激发波长为λex=514nm、最大发射波长为λem=547nm,DMH-PF与Mo(Ⅵ)形成1:2配合物使荧光猝灭,荧光猝灭量与Mo(Ⅵ)在0~0.072mg/L范围内呈线性关系,方法的检出限为0.0022mg/L,体系稳定,灵敏度高,采用液膜分离富集钼,可应用于合金钢和石墨中微量钼的测定。  相似文献   

8.
氯酚类物质测定新方法及其与人血清白蛋白的相互作用   总被引:1,自引:0,他引:1  
建立了氯酚类物质(CPs)新的检测方法,通过光谱学特征,探讨了CPs与人血清白蛋白(HSA)的结合反应机制。以2,4-二氯苯酚(2,4-DCP)为代表,考察了溶液酸度、试剂用量、反应温度和反应时间等因素对CPs—HSA体系荧光猝灭强度的影响。由Stern—Volmer方程求出2,4-DCP与HSA的猝灭常数(Kq)及反应热力学参数。结果表明,方法线性范围为0.075~0.65mg/L,检出限为0.226μg/L(以2,4-DCP计)。该方法与C18柱固相萃取技术相结合,用于水中CPs的测定,相对标准偏差小于2.9%,加标回收率为96%~106%。对荧光猝灭机理的探讨结果表明,2,4-DCP致HSA内源荧光猝灭以静态猝灭为主。  相似文献   

9.
在HCI介质中,NO2ˉ与5-氨基-1,2,3,4。四氢-1,4酞嗪二酮(ATPD)发生亚硝化反应,使ATPD的荧光猝灭,且其荧光猝灭程度与NO2ˉ量呈线性关系,从而建立了测定痕量NO2ˉ的新方法。该法线性范围为0.067—1.172μg/mL,方法检出限为0.70μg/L。本法已用于雨水中痕量NO2ˉ的测定。  相似文献   

10.
酪氨酸在辣根过氧化物酶催化下被H2O2氧化为强荧光物质S,姜黄素对其荧光产生猝灭作用,据此建立了测定姜黄素的新方法。姜黄素浓度c在0.10~16.0μg/mL范围内与F0/F(F和F0分别为姜黄素存在和不存在时产物S的荧光强度)呈线性关系,线性回归方程c=5.4552F0/F-5.4860,线性相关系数r=0.9996,检出限为0.02μg/mL,测定结果的相对标准偏差为0.79%(n=10),加标回收率为94.7%~102%。研究了pH值、各物质的量、反应时间、干扰离子等对测定的影响。该法可用于药物中姜黄素含量的测定。  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.
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   

13.
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   

14.
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   

15.
16.

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   

17.
The kinetics of the interaction between lithium carbonate and silica with various degrees of dispersion was investigated by TG and DTA methods. It was found that the utilization of pyrogenic silica with a specific surface area of about 300 m2g-1 instead of aerosil with one of 175 m2g-1 leads to an increase of the reaction rate between lithium carbonate and silica, which depends on the formation and growth of lithium orthosilicate crystals in the first stage, and is conditioned by the diffusion of lithium and oxygen ions through the lithium orthosilicate layer formed at temperatures above 800 K. This supposition is supported by the kinetic analysis results obtained with the use of the different models. The optimal regime of heating is recommended. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

18.
小环化合物中饱和碳质子化学位移的计算   总被引:3,自引:0,他引:3  
小环化合物由于其张力、构型、构象和各向异性效应等原因,环碳上质子化学位移缺乏规律性,难以预测,对此作者曾提出一种近似算法。本文根据303种小环化合物中饱和碳质子的化学位移实验数据,将适于计算这类质子化学位移的公式表述为:  相似文献   

19.
针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。  相似文献   

20.
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   

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