首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A novel flow injection analysis (FIA) method with Rayleigh light scattering (RLS) detection was developed for the determination of total protein concentrations. This method is based on the weak intensity of RLS of bromothymol blue (BB) (3',3"-dibromothymolsulfonephthalein) which can be enhanced by the addition of protein in weakly acidic solution. A common spectrofluorimeter was used as a detector. It was proved that the application of this method to quantify the total proteins in real samples by using bovine serum albumin was possible. The RLS signal was detected at lambda(ex)= lambda(em)=572 nm. The linear range was 7.0-70.0 microg mL(-1), the detection limit was 3.75 microg mL(-1), the reproducibility was 5.5% (n=7), and the sample throughput was 26 h(-1).  相似文献   

2.
廖立敏  李建凤  王碧 《结构化学》2011,30(10):1397-1402
A new molecular structural characterization(MSC)method called molecular vertexes correlative index(MVCI)was constructed in this paper.The index was used to describe the structures of 45 compounds and a quantitative structure-activity relationship(QSAR)model of toxicity(–lgEC50)was obtained through multiple linear regression(MLR)and stepwise multiple regression(SMR).The correlation coefficient(R)of the model was 0.912,and the standard deviation(SD)of the model was 0.525.The estimation stability and prediction ability of the model were strictly analyzed by both internal and external validations.The Leave-One-Out(LOO)Cross-Validation(CV)correlation coefficient(RCV)was 0.816 and the standard deviation(SDCV)was 0.739,respectively.For the external validation,the correlation coefficient(Rtest)was 0.905 and the standard deviation(SDtest)was 0.520,respectively.The results showed that the index was superior in molecular structural representation.The stability and predictability of the model were good.  相似文献   

3.
Saito K  Taninaka I  Murakami S  Muromatsu A 《Talanta》1998,46(5):1187-1194
The extraction behaviour of copper(II) and silver(I) with 2-(3,6,10,13-tetrathiacyclotetradec-1-oxy)hexanoic acid (TTCTOHA) was investigated at 25+/-0.1 degrees C and ionic strength of 0.1. The value of the logarithmic distribution coefficient, logK(DR) of TTCTOHA between octan-1-ol and aqueous phases was determined to be 4.13. Copper(II) was extracted with TTCTOHA into octan-1-ol as CuL(2), where L represents the anionic species of TTCTOHA. The logarithmic extraction constant, logK(ex(10)), was determined at -7.42. Silver(I) was extracted with TTCTOHA into octan-1-ol as AgL and Ag(2)L(2). The logarithmic distribution constant, logK(DC), of AgL was estimated to be 0.49. On the other hand, silver(I) was extracted into 1,2-dichloroethane as AgL and the logarithmic extraction constant, logK(ex(10)), was determined to be -2.24.  相似文献   

4.
Chung YC  Jan MS  Lin YC  Lin JH  Cheng WC  Fan CY 《Lab on a chip》2004,4(2):141-147
A high efficiency DNA extraction microchip was designed to extract DNA from lysed cells using immobilized beads and the solution flowing back and forth. This chip was able to increase the extraction efficiency by 2-fold when there was no serum. When serum existed in the solution, the extraction efficiency of immobilized beads was 88-fold higher than that of free beads. The extraction efficiency of the microchip was tested under different conditions and numbers of E. coli cells. When the number of E. coli cells was between 10(6) and 10(8) in 25 microl of whole blood, the extraction efficiency using immobilized beads was only slightly higher than that using free beads (10(0) to 10(1) fold). When the number of E. coli cells was in the range 10(4) to 10(6) in 25 microl of whole blood, the extraction efficiency of immobilized beads was greater than that of the free beads (10(1) to 10(2) fold). When the number of E. coli cells was lower, in the range 10(3) to 10(4) in 25 microl of whole blood, the extraction efficiency of immobilized beads was much higher than that of the free beads (10(2) to 10(3) fold). This study indicated that DNA could be efficiently extracted even when the number of bacterial cells was smaller (10(5) to 10(3)). This microfluidic extraction chip could find potential applications in rare sample genomic study.  相似文献   

5.
Polyethylene terephthalate (PET) was aminolyzed with 1,6‐diaminohexane (DAH) and then sialic acid (NANA) was immobilized via amidation onto the surface. The surface concentration of NANA was determined by 2‐thiobarbituric acid (TBA) test. The hemocompatibility of the resulting PET fabrics was evaluated based on complete blood count (CBC), coagulating times, and protein adsorption. The ability to remove lipopolysaccharide (LPS) was also determined. In addition, the effect of contacting NANA‐immobilizing PET on the suppression of reactive oxygen species (ROS) production was measured by the chemiluminescence (CL) method. The results show that by immobilizing NANA onto PET, the adhesion of platelet (PLt) was reduced, and oxidative stress was suppressed. The level of LPS was also greatly reduced. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

6.
利用腈氧化物的1,3-偶极加成反应,合成新诺明(SMZ),以1,2,3-三氯代丁醛肟(Ⅰa),经转化为α,β-二氯代丁腈氧化物(Ⅱa)后,与对乙酰氨基苯磺酰胺加成,继而就地进行环合、消除反应,浮5-甲基-3-(对乙酰氨基苯磺酰氨基)异噁唑(Ⅲa),(Ⅲa)水解即得SMZ(Ⅳa)。同时依法制得5-苯基-3-(对氨基苯磺酰氨基)异噁唑(Ⅳb)。  相似文献   

7.
A cleaner and simple spectrophotometric method using microflow analysis (muFA) was performed. It consisted of a T-junction with microcoil on a polymethyl methacrylate (PMMA) chip which was fabricated by laser ablation and a molded polydimethylsiloxane (PDMS) as top plate. The fabricated PMMA chip was integrated with light emitting diode (LED) as light source and spectrometer as detector. The proposed device was applied to determining copper in water samples using nitroso-R salt as chromogenic reagent at 495nm. It was found that the proposed muFA system was with less reagents and samples consumption with tiny waste generation. The relative standard deviation (R.S.D.) was less than 2% (n=11) with the percentage recovery of 98.0+/-1.7% (n=7). The linear range for determination of copper in water samples was over the range of 0.05-3.0mugmL(-1) with a correlation coefficient (r(2)) of 0.999. The limit of detection (3sigma) was 47ngmL(-1) with a sample throughput of 30h(-1).  相似文献   

8.
掺硼纳米TiO2对农药毒死蜱的光催化降解作用   总被引:1,自引:0,他引:1  
采用溶胶-凝胶法制备了掺杂硼的纳米TiO2,并用X射线衍射、红外光谱表征了产物的组成和结构.用制备好的掺硼纳米TiO2作为光催化剂对农药毒死蜱进行了光催化降解研究.结果表明:通过掺硼可以显著提高TiO2对毒死蜱的光催化效率.在硼掺杂量为3%,催化剂煅烧温度为500℃,煅烧时间为1 h,催化剂用量为15%时,毒死蜱的降解率最高.  相似文献   

9.
温度对掺杂球形Ni(OH)_2质子扩散的影响   总被引:1,自引:0,他引:1  
刘建华  杨敬武  唐致远 《电化学》2000,6(2):187-192
应用微电极恒电位阶跃法研究了在Ni(OH) 2 电极的阳极及阴极过程反应中 ,温度对球形Ni(OH) 2 的质子扩散系数和表观扩散活化能的影响 .研究表明 ,于Ni(OH) 2 中掺杂Co和Co +Zn后可降低其阳极和阴极过程的表观扩散活化能 ,增大质子扩散系数 ,掺Co的效果更加明显 ,而掺Zn则增大表观扩散活化能 ,降低了扩散系数 .这说明前者的掺入其作用是降低了质子扩散阻力使电极的反应活性增加、而后者的掺入则是增大了质子的扩散阻力而使电极反应活性降低 .  相似文献   

10.
以二氯磷酸苯酯(1)和γ-氨丙基三乙氧基硅烷(2)为原料,合成了一种新型的P-N-Si三元无卤阻燃剂--苯氧基-双-(三乙氧基硅丙基)磷酰胺(3),其结构经1H NMR, 31P NMR和FT-IR表征。研究了溶剂,反应温度,反应时间,投料比r[n(2) : n(1)]和缚酸剂对3产率的影响。结果表明:在最佳合成条件[THF为溶剂,三乙胺为缚酸剂,1 8 mmol, r=2.4,于40 ℃反应6 h]下, 3的产率为88.2%。利用TGA测试了3的阻燃性能。结果表明:3的初始分解温度为150 ℃, 600 ℃残炭为14.6%。3在棉纤维(c)中的添加量为15%(质量百分数,即c-315)时,600 ℃残炭为33.4%,高于c(7.6%)。  相似文献   

11.
The extraction and stripping behavior of yttrium(III) and iron(III) with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPA) was investigated and applied to liquid-membrane transport for their mutual separation. The extractability of yttrium(III) with EHPA was less than that of iron(III) at equilibrium, but the rates of extraction and stripping of iron(III) were slow. The carrier-mediated transport of yttrium(III) in the presence of iron(III) was investigated through a supported liquid membrane (SLM), impregnated with EHPA as a mobile carrier. Yttrium(III) with fast kinetics was selectively transported across an SLM from a dilute-acid solution into a sulfuric-acid stripping solution, while iron(III) with slow kinetics was hardly transported and was retained in the feed solution. Yttrium(III) was separated from iron(III) through the SLM and quantitative recovery was realized.  相似文献   

12.
Zhou Y  Nagaoka T  Li F  Zhu G 《Talanta》1999,48(2):461-467
A novel chemiluminescence (CL) system was evaluated for the determination of hydrogen peroxide, glucose and ascorbic acid based on hydrogen peroxide, which has a catalytic-cooxidative effect on the oxidation of luminol by KIO(4). Hydrogen peroxide can be directly determined by luminol-KIO(4)-H(2)O(2) CL system. The detection limit was 3.0x10(-8) mol l(-1) and the calibration graph was linear over the range of 2.0x10(-7)-6.0x10(-4) mol l(-1). The relative standard deviation of H(2)O(2) was 1.1% for 2.0x10(-6) mol l(-1) (N=11). Glucose was indirectly determined through measuring the H(2)O(2) generated by the oxidation of glucose in the presence of glucose oxidase at pH 7.6. The present method provides a source for H(2)O(2), which, in turn, coupled with the luminol-KIO(4)-H(2)O(2) CL reaction system. The CL was linearly correlated with glucose concentration of 0.6-110 mug ml(-1). The relative standard deviation was 2.1% for 10 mug ml(-1) (N=11). Detection limit of glucose was 0.08 mug ml(-1). Ascorbic acid was also indirectly determined by the suppression of luminol-KIO(4)-H(2)O(2) CL system. The calibration curve was linear over the range of 1.0x10(-7)-1.0x10(-5) mol l(-1) of ascorbic acid. The relative standard deviation was 1.0% for 8.0x10(-7) mol l(-1) (N=11). Detection limit of ascorbic acid was 6.0x10(-8) mol l(-1). These proposed methods have been applied to determine glucose, ascorbic acid in tablets and injection.  相似文献   

13.
The sorption of Pu(VI) onto TiO(2) was studied as a function of pH (2-10) and Pu concentration (10(-8)-10(-4) M) under an N(2) atmosphere, in 0.016 and 0.1 M NaClO(4). A batch-wise method was used, in which pH was measured in separate experimental containers after removal of a sample to determine the amount of Pu that had been sorbed. As Pu is radioactive, it was used as a tracer and measured by liquid scintillation counting. No ionic strength dependence was discerned, which was taken as an indication of inner sphere complex formation. In the interval of pH 2-7 the system could be described by the formation of two positively charged surface complexes using a 1-pK Stern model. Sorption of the plutonyl ion (PuO(2)(2+)) and the first hydrolysis species (PuO(2)(OH)(+)) was estimated using FITEQL to logK(1)=6.9 and logK(2)=1.4, respectively.  相似文献   

14.
Wei Y  Oshima M  Motomizu S 《The Analyst》2002,127(3):424-427
Monitoring the removal of carbonate from alkali metal hydroxide (MOH, M = K, Na) solutions with calcium oxide (CaO) was studied using a newly developed method for the determination of trace amounts of total carbonate (TC) in alkaline solutions based on a flow injection (FI) technique coupled with a gas diffusion system. The optimized conditions of the FI system were as follows: the flow rate of each carrier, reaction solution (H2SO4) and receptor solution (Cresol Red, pH 8.9) was 0.25 ml min(-1), the sample size was 0.1 ml and the concentration of H2SO4 in the reaction solution was 0.09 M. The limit of detection of TC by the proposed method was 4 x 10(-7) M. The removal efficiency of carbonate was affected by the amount of CaO added, the shaking time of the solutions and the concentration of MOH. For 1 M NaOH and KOH solution, the removal efficiency of carbonate was about 99% and the concentration of residual carbonate was 4 x 10(-5) and 1.2 X 10(-4) M, respectively, when the amount of CaO added was 2 g l(-1) and the shaking time was 16 h.  相似文献   

15.
The discharge from a bicycle factory in Dar-es-Salaam was analysed for dissolved trace metals so as to monitor what was being introduced onto the environment. An X-ray Fluorescence Spectrophotometer with a Si (Li) detector connected to a multichannel analyser Canberra 40 series was used for the analysis. Computation of the peaks and results was done by a Professional Deck 350 computer. The elements contained in the discharge were Ca (596 ppm), Ti (369 ppm), Cr (11 ppm), Zn (0.98%) and Sr (73.5 ppm). Further analysis of the speciation of chromium revealed that there was Cr(III) (9 ppm) and Cr(VI) 2 ppm. The level of Cr(VI) was considered too high considering its toxicity.  相似文献   

16.
The reactive uptake kinetics of ClONO(2) on pure and doped water-ice surfaces have been studied using a coated wall flow tube reactor coupled to an electron impact mass spectrometer. Experiments have been conducted on frozen film ice surfaces in the temperature range 208-228 K with P((ClONO)(2)) < or = 10(-6) Torr. The uptake coefficient (gamma) of ClONO(2) on pure ice was time dependent with a maximum value of gamma(max) approximately 0.1. On HNO(3)-doped ice at 218 K the gamma(max) was 0.02. HOCl formation was detected in both experiments. On HCl-doped ice, uptake was gas-phase diffusion limited (gamma > 0.1) and gas-phase Cl(2) was formed. The uptake of HCl on ice continuously doped with HNO(3) was reversible such that there was no net uptake of HCl once the equilibrium surface coverage was established. The data were well described by a single site 2-species competitive Langmuir adsorption isotherm. The surface coverage of HCl on HNO(3)-doped ice was an order of magnitude lower than on bare ice for a given temperature and P(HCl). ClONO(2) uptake on this HCl/HNO(3)-doped ice was studied as a function of P(HCl). gamma(max) was no longer gas-phase diffusion limited and was found to be linearly dependent on the surface concentration of HCl. Under conditions of low HCl surface concentration, hydrolysis of ClONO(2) and reaction with HCl were competing such that both Cl(2) and HOCl were formed. A numerical model was used to simulate the experimental results and to aid in the parametrization of ClONO(2) reactivity on cirrus ice clouds in the upper troposphere.  相似文献   

17.
This paper describes experiments demonstrating the high mass-resolving power of the MULTUM II multi-turn type time-of-flight (ToF) mass spectrometer with a 1.308-meter circuit controlled by four toroidal electric sector fields(1) and an electron ionization (EI) ion source. A mass resolution of 250,000 [full-width at half maximum: (FWHM)] was obtained for N(2)(+) after a flight time of 9.0 ms (flight cycles: 1,200, flight length: 1,500 M). A doublet of (12)C(5)H(5)(14)N and (13)C(12)C(5)H(6) (m/Deltam = 9,746; Deltam: mass difference of doublet, m: mass of lighter ion of doublet) was separated and a mass resolution of 91,000 (FWHM) was obtained. A doublet of CDCl(2) and CH(2)Cl(2) (m/Deltam = 54,162) was also separated. A mass resolution of 115,000 (FWHM) was then achieved. When one peak of these doublets was used as a calibrant, the mass of the other peak was determined within a few ppm by mass difference. The ToF depending on the square of m/z was significantly larger than the systematic errors in the ToF, so that good mass accuracy was obtained by one-point mass determination.  相似文献   

18.
The behaviour of the Nickel(Ⅱ) ion in the presence of dimethyl-glyoxime (DMG) on the hanging mercury drop electrode in NH_3/NH_4Cl media was investigated with different electrochemical techniques. It was found that: (1) the reactant was Ni(Ⅱ) complex with DMG, Ni(Ⅱ)A_2, adsorbed on the electrode surface; (2) the intermediate was Ni(Ⅰ)A_2 and (3) the product was metal amalgam Ni(0)(Hg). Two electrons were transferred in the overall reaction and the transfer coefficient was 1.8 which was measured experimentally. From experimental results, it was obvious that the reaction orders with respect to Ni(Ⅱ), DMG and H~+ were 1,2, and 1, respectively. A new compound, X, was detected. The reaction scheme could be written as followsNi(Ⅱ)A_2+Hg<=>Ni(Ⅱ)A_2(ads)(Hg)Ni(Ⅱ)A_2(ads)(Hg)+e~-<=>Ni(Ⅰ)A_2(ads)(Hg)Ni(Ⅰ)A_2(ads)(Hg)+H~++e~-→Ni(0)(Hg)+HA(des)+A~-(des)→X+Hg  相似文献   

19.
A hybrid organic-inorganic material based on vermiculite was prepared to remove diethyl phthalate (DEP) from aqueous solution. Natural vermiculite was activated with HCl to improve the specific surface area and was then modified by silanization using trimethylchlorosilane. Organovermiculite prepared by ion exchange with hexadecyl trimethylammonium bromide (HDTMAB) was also tested for comparison. The leaching of 2 mol L(-1) HCl at 80°C increased the specific surface area of vermiculite from 14.4 to 500.0m(2)g(-1), and the average pore-diameter was decreased from 7.90 nm to 2.75 nm. Fourier transform infrared spectroscopy (FTIR) spectra indicated that trimethysilyl groups were grafted covalently on the surface of acid vermiculites. The specific surface area of trimethylchlorosilane-modified acid vermiculites (TMAVs) (355.4 m(2) g(-1)) was much larger than that of organovermiculite (6.0 m(2) g(-1)). The isotherm adsorption experiments of DEP showed that TMAVs exhibited linear isotherms, suggesting that the uptake of DEP was controlled by partitioning mechanism. The maximal partition coefficient (K(d)) of TMAVs was 3.1 times higher than that of organovermiculite, implying that TMAVs had stronger organic affinity than organovermiculite. The results demonstrate that the adsorption capacity and mechanism of organoclays were controlled by the specific surface area and organic loading, whereas the length of alkyl chain of organic modifier was not the key factor.  相似文献   

20.
纳米TiO2表面对Cd2+的吸附与光化学还原过程的QCM研究   总被引:2,自引:0,他引:2  
用石英晶体微天平(QCM)现场技术研究了Cd2+在纳米TiO2表面的吸附与光化学还原过程.研究结果表明,Cd2+在纳米TiO2表面的吸附量受溶液的浓度、pH值和不同添加物的影响.当pH<7时, Cd2+不发生吸附;pH=7时,Cd2+在TiO2膜上的吸附量接近于15.2 mg/g.在紫外光光照下, Cd2+不发生光化学反应,但在溶液中加入NO-3和HCO-2后, Cd2+在电极表面可发生光化学反应,分别生成了CdO·Cd(OH)2和Cd.当醇类物质加入后, QCM的频率略有下降, 但没有观察到单质Cd的生成.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号