pH值对亚甲基蓝/β-环糊精包合常数的影响

本文用紫外-可见分光光度法测定了亚甲基蓝/β-环糊精包合物的包合平衡常数(简称包合常数K)。并探讨了包合物溶液放置时间、亚甲基蓝初始浓度、溶液pH值对包合常数的影响。结果表明:亚甲基蓝/β-环糊精包合物的包结比为1∶1,溶液放置时间和亚甲基蓝初始浓度不影响亚甲基蓝/β-环糊精的包合常数,溶液pH对包合常数有较大的影响,pH=3~10时包合常数随pH值的增加而增加,包合常数在pH=7时为1×104L/mo。l     

SnO_2@PW_(12)的制备及对废水中亚甲基蓝的降解

采用简单浸渍法制备了SnO2@PW12催化材料,通过XRD和TEM对其结构进行了表征,研究了该催化材料对有机染料亚甲基蓝降解的催化活性。讨论了催化剂投加量、亚甲基蓝溶液的初始浓度、酸度等对催化降解效果的影响。结果表明,当溶液酸度为pH=4,催化剂用量为50mg/L,浓度为5mg/L亚甲基蓝溶液在30W的紫外灯下照射40min脱色率可达89.72%。SnO2@PW12光催化降解亚甲基蓝为一级动力学反应。     

激光二极管诱导荧光高灵敏检测亚甲基蓝

建立了水中微量亚甲基蓝的高灵敏激光诱导荧光检测方法。利用638 nm/100 mW激光二极管产生激光,激发亚甲基蓝使之产生最大波长为662 nm的荧光,该荧光强度与亚甲基蓝含量成线性关系,亚甲基蓝在1～180μg/L浓度范围内线性关系良好(R~2=0.9998),荧光强度在60 min内基本稳定。使用组装的激光诱导荧光检测系统对亚甲基蓝试样进行测试,结果良好。该法对水样品中痕量亚甲基蓝的测定具有应用价值。     

超高效液相色谱-串联四极杆质谱法筛查青黛中非法掺入的染色物质

建立了超高效液相色谱-质谱联用法测定青黛中非法掺入的染色物质孔雀石绿、隐色孔雀石绿、天青A、天青B、天青C和亚甲基蓝的检测方法.样品经乙腈溶液(含5%甲酸)提取,采用超高效液相色谱-串联三重四极杆质谱(UPLC-MS/MS)的多反应监测模式(MRM)进行定性和定量检测,其中孔雀石绿、隐色孔雀石绿内标法定量,天青A、天青B、天青C、亚甲基蓝外标法定量.6种染色物质测定的线性范围在1～30 ng/m L之间,孔雀石绿、隐色孔雀石绿、天青A、天青B、天青C、亚甲基蓝的检出限分别为0.5、0.5、1.0、1.0、1.0、1.0 ng/g,定量限分别为1.0、1.0、2.0、2.0、2.0、2.0 ng/g,3个水平的回收率在79.7%～119.7%之间,精密度的RSD%在0.7%～1.8%之间.方法前处理简单,灵敏度高,适用青黛中非法掺入的染色物质孔雀石绿、隐色孔雀石绿、天青A、天青B、天青C和亚甲基蓝的快速检测.     

交联聚丙烯酰胺溶液染色研究

采用显微镜研究了预交联聚合物凝胶溶液的染色过程,结果表明由于静电作用,亚甲基蓝溶液中阳离子基团与凝胶颗粒中的阴离子基团相互作用形成一种深蓝色的缔合物;交联聚物线团也可以与亚甲基蓝分子形成深蓝色的缔合物,使交联聚合物线团显色,能够直接观测到交联聚合物线团在溶液中的形态。采用扫描电镜、动态光散射、流变仪和岩心封堵实验研究了染色后交联聚合物的线团形态尺寸和溶液的流变性、封堵特性。结果表明,染色后的交联聚合物线团仍是几百纳米左右的在水中分散的球形体,在形态和尺寸上与未染色的交联聚合物溶液没有发生较大的变化;染色后交联聚合物溶液在一定剪切速率范围内表现为胀流性和负触变性。     

一种应用于活细胞中检测Hg(Ⅱ)的苯并噻唑类荧光探针（英文）

合成和表征了一种苯并噻唑类的荧光探针(YH1),并用光谱法研究了它对不同金属离子的响应。结果表明:YH1对Hg2+显示出好的选择性和灵敏度,与Hg2+作用后,在紫外光的激发下它的溶液颜色由蓝色变为无色。在1.4~8.8μmol·L-1浓度的范围内,YH1的荧光强度与Hg2+浓度有线性关系,其对Hg2+的检出限为0.56μmol·L-1。此外,YH1可跨过细胞膜,细胞毒性低,还可应用于He La活细胞中对Hg2+进行荧光成像。     

亚甲基蓝及NH4+,Na+,K+与SiO2的表面配位常数测定

采用动电位、等温吸附方法研究了不同pH条件下SiO2的表面电性和对有机染料-亚甲基蓝的吸附行为,运用WinSGW软件计算得出亚甲基蓝在SiO2颗粒表面配位常数.研究发现亚甲基蓝通过静电和氢键作用吸附,相应的化学反应模型和表面配位常数分别为≡Si2O-+MB+≡Si2OMB(lg K=4.48)和≡SiOH+MB+≡SiOHMB+(lg K=2.30).在此基础上研究了一价阳离子NH+4,Na+,K+对亚甲基蓝在SiO2表面吸附的影响,根据WinSGW软件模拟得到的NH+4,Na+,K+与SiO2表面的配位常数分别为:≡Si2O-+M+≡Si2OM[lg K=3.76,2.73,2.58(M+=NH+4,Na+,K+).在铵根离子浓度高时,还会在表面上发生≡SiOH+NH3+MB+≡SiOHNH3MB+(lg K=6.69)化学反应而生成包含有三种组分的≡SiOHNH3MB+表面三元配合物.研究结果可为了解有机染料和氨氮在被污染土壤和水体中的分布提供一定的理论依据.     

一种应用于活细胞中检测Hg(Ⅱ)的苯并噻唑类荧光探针

合成和表征了一种苯并噻唑类的荧光探针(YH1),并用光谱法研究了它对不同金属离子的响应。结果表明:YH1对Hg2+显示出好的选择性和灵敏度,与Hg2+作用后,在紫外光的激发下它的溶液颜色由蓝色变为无色。在1.4~8.8μmol·L-1浓度的范围内,YH1的荧光强度与Hg2+浓度有线性关系,其对Hg2+的检出限为0.56μmol·L-1。此外,YH1可跨过细胞膜,细胞毒性低,还可应用于He La活细胞中对Hg2+进行荧光成像。     

PMBNPs/MWCNTs/Nafion修饰电极差分脉冲伏安法测定利血平

合成了一种新型的导电聚合物纳米粒子-多聚亚甲基蓝纳米粒子(PMBNPs),以扫描电镜、紫外光谱及荧光光谱对PMBNPs进行了表征。将PMBNPs固定化在MWVCNTs/Nafion修饰电极表面,制备了PMBNPs/MWCNTs/Nafion修饰电极。通过循环伏安法和电化学阻抗谱对其电化学性质进行了表征,结果表明较之亚甲基蓝溶液和电化学聚合的亚甲基蓝,由多个亚甲基蓝分子组成的纳米粒子制备成的修饰电极具有良好的电活性,可以实现检测信号的放大。据此,将PMBNPs/MWCNTs/Nafion修饰电极用于利血平的电化学检测。     

CuW_(11)Cd/PANI掺杂材料的制备、表征及光催化性能

采用化学氧化法制得K_8[CuW_(11)CdO_(40)]/PANI掺杂材料,并用IR、UV、XRD、EDS、SEM对所合成的掺杂材料进行了表征。并利用所合成K_8[CuW_(11)CdO_(40)]/PANI掺杂材料为催化剂,研究了对亚甲基蓝溶液光降解催化活性。通过实验确定了光降解的最佳条件为:亚甲基蓝溶液初始pH为2,亚甲基蓝溶液初始浓度为10mg·L~(-1),催化剂用量为0.08 g,在光照100 min,亚甲基蓝溶液的脱色率为98.11%。因此,K_8[CuW_(11)CdO_(40)]/PANI掺杂材料是一种很好的光降解催化剂。     

Combination of liquid-phase hollow fiber membrane microextraction with gas chromatography-negative chemical ionization mass spectrometry for the determination of dichlorophenol isomers in water and urine

A method for the determination of trace amount of dichlorophenol isomers in urine samples using the combination of liquid-phase hollow fiber microextraction (LPME-HF) with gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-MS) has been demonstrated. The method has been optimized with respect to several parameters including the effects of negative chemical ionization (NCI) reagent pressure, the hollow fiber length, extraction time, stirring rate, sample pH and salt concentration for the determination of dichlorophenol isomers in water. The correlation coefficient (r²) of the calibration curves for 2,5-dichlorophenol, 2,3-dichlorophenol, 2,6-dichlorophenol, 3,5-dichlorophenol and 3,4-dichlorophenol were 0.988, 0.981, 0.985, 0.971 and 0.994, respectively. The average recovery rates for 2,5-dichlorophenol, 2,3-dichlorophenol, 2,6-dichlorophenol, 3,5-dichlorophenol and 3,4-dichlorophenol were 0.97, 0.93, 0.96, 0.95 and 0.95, respectively (n = 3 for each dichlorophenol) indicate that the methodology is feasible for the determination of trace amounts of dichlorophenol isomers in water and urine samples. Limits of detection (LOD) have been found to be in the range of 5-20 ng/ml. In addition, differentiation of the five dichlorophenol isomers is an easy task using the current approach of combining LPME-HF with NCI-GC-MS technique since they exhibit different NCI spectra.     

Development of a simple method for biotoxicity measurement using ultramicroelectrode array under non-deaerated condition

In this paper, a mediated method by using ferricyanide under non-deaerated condition for biotoxicity measurement was proposed. Ultramicroelectrode array (UMEA) was employed for effectively amplify the electrochemical signal from the total limiting currents to distinguish a little change in toxicity. Five species of microorganisms including two bacilli (Escherichia coli and Enterobacter cloacae), two pseudomonas (Pseudomonas fluorescens and Pseucomonas putida) and one fungus (Trichosporon cutaneum) were employed. 3,5-dichlorophenol (DCP) was taken as the reference toxicant. The IC50 values we obtained were similar with the values obtained using in the deaerated method. E. coli was used as model test microorganism. The final concentration of ferricyanide is 45 mM, E. coli OD600 8 and 1 h incubation were taken in optimum conditions in this study. Four heavy metal ions (Cr⁶⁺, Hg²⁺, Cd²⁺ and Bi³⁺) were examined under the optimum conditions. Comparison with the results reported previously has confirmed that this method provided a simple and rapid alternative to toxicity screening of chemicals, especially advantageous for in situ monitoring of water system.     

A BODIPY‐based Fluorescent Probe for Thiophenol

Thiophenol has been listed as one of the main sources of pollution. Sensitive probes for thiophenol are very significant. Herein, a BODIPY‐based fluorescent probe, named BDP, for poisonous thiophenol detection has been reported. BDP shows rapid response (15 s) and clear fluorescence enhancement (30 folds) to thiophenol in solution. The intensity of fluorescence and concentration of thiophenol have a good linear relationship. The detection limit is as low as 13.6 nmol · L⁻¹. BDP is stable towards pH and light radiation. Cell experiments demonstrate that BDP has good cell membrane penetrability, low cell toxicity and excellent imaging properties in living cells. Therefore, BDP has significant value on the detection of thiophenol in solution and in living cell.     

Analysis of phenols in water by high-performance liquid chromatography using coumarin-6-sulfonyl chloride as a fluorogenic precolumn label

A simple, sensitive and rapid reversed-phase high-performance liquid chromatography (RP-HPLC) method is proposed for the analysis of some environmentally important phenols in water. The use of coumarin-6-sulphonyl chloride (C6SCl) as a fluorescence-labeling reagent has been investigated. The compound reacts with phenols within 20 min under mild conditions (ambient temperature, pH 9.0) to give sulphonates that can be separated by RP-HPLC employing fluorescence detection at lambda(ex) = 360 and lambda(em) = 460 nm. The optimum conditions for fluorescence, derivatization and chromatographic separation have been established and detection limits in the range 0.1-0.9 microg l(-1) were obtained for the studied compounds. The calibration curves were linear for the range 6-200 microg l(-1) for phenol, 3-200 microg l(-1) for 2-chlorophenol, 4-chlorophenol and 2,3,5-trichlorophenol and for the range of 3-100 microg l(-1) for 2,3-dichlorophenol and 3,5-dichlorophenol. The practical applicability of the method to environmental samples was demonstrated by analyzing drinking and industrial water samples spiked with the phenolic compounds.     

Electrical impedance spectroscopy for detection of bacterial cells in suspensions using interdigitated microelectrodes

In this study, we present a new, simple and rapid impedance method to detect bacterial cells by making use of the impedance properties of bacterial cell suspensions using interdigitated microelectrodes. It was found that bacterial cell suspensions in deionized (DI) water with different cell concentrations could generate different electrical impedance spectral responses, whereas cell suspensions in phosphate buffered saline (PBS) solution could not produce any significant differences in impedance spectra in response to different cell concentrations. In DI water suspensions, impedance at 1 kHz decreased with the increasing cell concentrations in the suspensions. The impedance of cell suspensions in DI water was discussed and found that it was resulted from the cell wall charges and the release of ions or other osmolytes from the cells. A linear relationship between the impedance and the logarithmic value of the cell concentration was found in the cell concentration range from 10⁶ to 10¹⁰ cfu/ml, which can be expressed by a regression equation of Z (kΩ) = −2.06 log C (cells/20 μl) + 5.23 with R² = 0.98. The detection limit was calculated to be 3.45 × 10⁶ cfu/ml, which is comparable with many label-free immunosensors for detection of pathogenic bacteria reported in the literature. To achieve the selectivity of this method, we also demonstrated the feasibility of integrating magnetic separation to this impedance method. This study has demonstrated that bacterial cell concentration can be inferred by measuring the impedance of cell suspensions in DI water. This new detection mechanism could be an alternative to current impedance methods that have been reported for the detection of bacterial cells, e.g. impedance microbiology and electrical/electrochemical impedance biosensors.     

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by high-performance liquid chromatography with ultraviolet detection and liquid chromatography-tandem mass spectrometry for the determination of triclosan and 2,4-dichlorophenol in water samples

A novel, simple and efficient dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) technique coupled with high-performance liquid chromatography with ultraviolet detection (HPLC-UV) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of triclosan and its degradation product 2,4-dichlorophenol in real water samples. The extraction solvent used in this work is of low density, low volatility, low toxicity and proper melting point around room temperature. The extractant droplets can be collected easily by solidifying it at a lower temperature. Parameters that affect the extraction efficiency, including type and volume of extraction solvent and dispersive solvent, salt effect, pH and extraction time, were investigated and optimized in a 5 mL sample system by HPLC-UV. Under the optimum conditions (extraction solvent: 12 μL of 1-dodecanol; dispersive solvent: 300 of μL acetonitrile; sample pH: 6.0; extraction time: 1 min), the limits of detection (LODs) of the pretreatment method combined with LC-MS/MS were in the range of 0.002-0.02 μg L(-1) which are lower than or comparable with other reported approaches applied to the determination of the same compounds. Wide linearities, good precisions and satisfactory relative recoveries were also obtained. The proposed technique was successfully applied to determine triclosan and 2,4-dichlorophenol in real water samples.     

Transformation of 2,4-dichlorophenol by H2O2/UV-C, Fenton and photo-Fenton processes: Oxidation products and toxicity evolution

In the present study, H₂O₂/UV-C, Fenton and photo-Fenton treatment of 2,4-dichlorophenol was compared in terms of oxidation products and acute toxicity. The oxidation products were identified by gas chromatography-mass spectroscopy, high performance liquid chromatography and ion chromatography, whereas changes in acute toxicity were evaluated by the Vibrio fischeri luminescence inhibition assay. H₂O₂/UV-C and photo-Fenton processes ensured complete 2,4-dichlorophenolremoval, detoxification and significant mineralization. Hydroquinone and formic acid were identified as the common oxidation products of the studied advanced oxidation processes investigated. 3,5-dichloro-2-hydroxybenzaldehyde, phenol, 4-chlorophenol and 2,5-dichlorohydroquinone were identified as the additional H₂O₂/UV-C oxidation products of 2,4-dichlorophenol. Acute toxicity decreased with decreasing 2,4-dichlorophenol and increasing chloride release.     

Pervaporation separation of aqueous chlorophenols by a novel polyurethane urea–poly (methyl methacrylate) interpenetrating network membrane

A novel polymer membrane system consisting of interpenetrating network (IPN) of hydroxy terminated polybutadiene (HTPB) based polyurethane urea (PUU)–poly (methyl methacrylate) (PMMA) has been designed and developed as highly permselective membrane for pervaporation separation of toxic p-chlorophenol and 2,4-dichlorophenol from their dilute aqueous solutions. It was observed that 3 ppm 2,4-dichlorophenol in water could be reduced to 0.3 ppm 2,4-dichlorophenol using a PUU–PMMA IPN membrane of 28 cm² area and 150 μm thickness. This membrane has shown high selectivity towards p-chlorophenol and 2,4-dichlorophenol at very low concentration in feed. Feed concentration of p-chlorophenol was varied from 1000 to 7000 ppm and that of 2,4-dichlorophenol was varied from 3 to 4000 ppm. Fifty seven percent 2,4-dichlorophenol in permeate was obtained from 3 ppm concentration in feed compared to 87% 2,4-dichlorophenol in permeate from 1000 ppm in feed. Pervaporation studies were carried out by varying the temperature of feed, membrane thickness and PMMA content in the membrane. The results of this investigation have revealed that these membranes would be suitable for separation of chlorophenols from industrial effluents.     

A sensitive, rapid ferricyanide-mediated toxicity bioassay developed using Escherichia coli

A need for rapid toxicity techniques has seen recent research into developing new microbiological assays and characterising their toxicity responses using a range of substances. A microbiological bioassay that determines changes in ferricyanide-mediated respiration for toxicity measurement (FM-TOX) shows particular promise. The development and optimisation of an improved FM-TOX method, incorporating novel features, is described using Escherichia coli as the biocatalyst. Omission of an exogenous carbon source, used in previously described FM-TOX assays, substantially improves the assay sensitivity. In addition, the development of a two-step procedure (toxicant exposure followed by determination of microbial respiratory activity) was found to enhance the inhibition of E. coli by 3,5-dichlorophenol and four other toxicants, compared to single-step procedures. Other assay parameters, such as the ferricyanide concentration, exposure times and optical density of the biocatalyst were also optimised, sometimes based on practical aspects. Toxicity tests were carried out using the adopted technique on both organic and inorganic toxicants, with classic sigmoid-shaped dose-response curves observed, as well as some non-standard responses. IC₅₀ data is presented for a number of common toxicants. The optimised assay provides a good foundation for further toxicity testing using E. coli, as well as the potential for expanding the technique to utilise other bacteria with complementary toxicity responses, thereby allowing use of the assay in a range of applications.     

Sensitive measurement of methylene blue active substances by attenuated total reflection spectrometry with a trimethylsilane-modified glass slab optical waveguide

Attenuated total reflection spectrometry with a slab optical waveguide (SOWG) was explored for the simple, rapid and sensitive measurement of total anionic surfactants by the methylene blue active substance (MBAS) method. A fused-silica sheet used as a guiding layer was modified with trimethylsilane (TMS) to extract and concentrate the MBASs on the SOWG surface. Based on preliminary studies of the adsorption behavior and visible ATR spectrum of MB on the modified silica surface, a detection wavelength of 600 nm was chosen for the sensitive measurement of anionic surfactants. When the concentration of MB was set at 10 microM in the final measurement solution, the calibration curve for a typical anionic surfactant (sodium dodecylbenzenesulfonate) was linear up to 0.6 microM and the detection limit was 0.07 microM. The proposed method was applied to the determination of total anionic surfactants in river water.