Self-aggregation of surfactants in water solution by NMR

Dynamic behavior of surfactant molecules, sodium dodecyl sulfonate (SDSN), cetyl trimethyl ammonium bromide (CTAB) and triton X-100, and their micelles in water solution at various concentrations were studied by chemical shift, self diffusion coefficient (D) and nuclear magnetic resonance relaxation (T₁ and T₂) measurements. Experimental results show that there exist turning points at surfactant concentration (C) nearby the critical micelle concentration (cmc) for all of the above-mentioned parameters, which approach the constant values when C equals 5 to 10 times cmc. T₁ and T₂ measurements show that when C<cmc, Triton X-100 molecules exhibit fast isotropic motion in water solution. After micellization, the motion of hydrophobic chains is far away from the extreme narrowing condition, however, the long hydrophilic oxyethylene chains move relatively freely, although their T₁ and T₂ become shorter in comparison with those of the molecules in mono-molecular state. The behavior of the hydrophobic chains within the micellar core of SDSN and CTAB is similar to that of Triton X-100 to some extent. Project supported by the National Climbing Project.     

单发肺炎实变型肺MALT淋巴瘤的多排螺旋CT诊断及鉴别

目的分析单发肺炎实变型肺黏膜相关淋巴组织（MALT）淋巴瘤的多排螺旋CT（MSCT）表现,以提高其诊断及鉴别诊断水平。方法回顾性分析11例患者经手术病理证实的单发肺炎实变型肺MALT淋巴瘤的MSCT和临床资料。结果11例患者中右肺中叶5例,下叶2例,左肺上叶1例,下叶3例;大叶性实变7例,节段性实变3例,非节段性实变1例;2例病灶边缘模糊,类似于炎症,6例边缘模糊程度介于炎症与肺癌之间,3例边缘相对清楚;同邻近胸大肌密度相比较,9例病灶呈略低密度,2例与胸大肌密度接近,CT值39.6～53.3 Hu,平均42.5 Hu;11例病灶内部均未见明显坏死、囊变,9例病灶内见形态及走行相对正常的“空气支气管征”,其中3例内部同时伴有小囊腔;7例CT增强检查,均呈轻～中度较均匀强化,CT值50.5～85.7 Hu,平均66.1 Hu;5例病灶内见“血管漂浮征”;11例病灶均未见明显胸腔积液,2例病灶邻近胸膜增厚,2例伴有纵隔内淋巴结肿大。结论单发肺炎实变型肺MALT淋巴瘤CT上往往表现为肿瘤样的实变、炎症样模糊边缘,多轻、中度较均匀强化,内部常有固有结构的残留,部分可见“空气支气管征”及“血管漂浮征”。MSCT对该肿瘤的的诊断及鉴别具有一定价值。     

Cloud-Point Extraction and Spectrophotometric Determination of Trace Quantities of Bismuth in Environmental Water and Biological Samples

ABSTRACT

A cloud-point extraction (CPE) process using the nonionic surfactant Triton X-114 to extract bismuth from aqueous solutions was investigated. The method is based on the complexation reaction of Bi(III) with 4-(2-benzothiazolylazo)2,2′-biphenyldiol (BTABD) and micelle-mediated extraction of the complex. The optimal extraction and reaction conditions (e.g., pH, reagent concentration, surfactant concentration, and effect of time) were studied. The analytical characteristics of the method (e.g., linear range, molar absorptivity, Sandell sensitivity, optimum Ringbom concentration ranges, limits of detection and quantification, preconcentration factor, and improvement factors) were obtained. Linearity was obeyed in the range of 2.50–85.0 ng mL^?1 of Bi(III) ion. The detection limit of the method was 0.75 ng mL^?1 of Bi(III) ion. The interference effect of some anions and cations was also tested. The method was applied to the determination of bismuth in environmental water, human hair, and urine samples.     

曙红Y-Triton X-100疏水性氢键纳米微粒的吸收、荧光及共振瑞利散射光谱及其分析应用

在pH2.4～2.8的酸性介质中,曙红Y分子(H2L)取代水分子而与Triton X-100形成氢键缔合物.该疏水性的氢键缔合物,在水相的"挤压"作用和范德华力的作用下,能进一步聚集形成纳米微粒.此时将引起吸收光谱的变化和荧光猝灭,并导致共振瑞利散射(RRS)显著增强,为建立褪色分光光度法、荧光猝灭法和共振瑞利散射法测定Triton X-100创造了条件.三种方法均有较高的灵敏度.其中以RRS法灵敏度最高,对于Triton X-100的检出限为20.6ng/mL.本文研究了曙红Y与Triton X-100相互作用的适宜条件和对吸收、荧光和RRS光谱的影响.考察了共存物质的影响,表明方法有良好的选择性.发展和建立了灵敏、简便、快速测定Triton X-100的分光光度、荧光猝灭法和RRS新方法.文中还结合红外光谱、透射电子显微镜技术和量子化学方法对曙红Y-Triton X-100氢键缔合物及纳米微粒的形成以及对相应的光谱特性的影响进行了讨论,并研究了方法在环境分析中的应用.     

Development of a cloud point extraction and preconcentration method for silver prior to flame atomic absorption spectrometry

The possibility was investigated of using 2-mercaptobenzothiazole (MBT) for Ag(I) concentration by micellar extraction at cloud point (CP) temperature and subsequent determination by flame atomic absorption spectrometry (FAAS). The method is based on the complexation of Ag(I) with 2-mercaptobenzothiazole (MBT) in the presence of non-ionic micelles of Triton X-114. The effect of experimental conditions such as pH, concentration of chelating agent and surfactant, equilibration temperature and time on cloud point extraction was studied. Under the optimum conditions, the preconcentration of 10 mL of water sample in the presence of 0.1% Triton X-114 and 2 × 10⁻⁴ mol L⁻¹ 2-mercaptobenzothiazole permitted the detection of 2.2 ng mL⁻¹ silver. The calibration graph was linear in the range of 10–200 ng mL⁻¹, and the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Ag(I) in water samples.     

HX环的存在性

自李洪兴１９９１年提出了ＨＸ环这一问题以来,一直有这么一个问题没有解决,即是否存在非平凡的ＨＸ环的例子？但至今既没有找到非平凡的ＨＸ环,也没有证明任一环Ｒ上仅存在平凡的ＨＸ环,钟育彬１９９５年证明了一类环上仅存在平凡的ＨＸ环,那么,是否所有环仅存在平凡的ＨＸ环呢？针对这一点,本文作进上步研究,构造了一个非平凡的ＨＸ环,并建立了ＨＸ环上的同态与同构定理,为进上步研究ＨＸ环奠定了基础。     

季节调整中消除节假日因素方法的改进及其在我国的应用

本文首先对X-12-ARIMA季节调整方法中消除节假日因素的思路进行了简要的回顾。接着,从休闲日和工作日的独特视角指出季节调整方法中消除节假日因素思路的不足,分析了不同节假日因素对经济数据的不同影响。最后,根据我国一些特殊节假日的实际情况,在借鉴X-12- ARIMA季节调整中处理节假日方法的基础上提出了消除中国节假日因素的思路,并提供了一个实例。     

The application of cloud point preconcentration for the determination of Cu in real samples by flame atomic absorption spectrometry

A simple and practical preconcentration method using cloud point approach is proposed for the extraction and preconcentration of Cu (II). The analyte in the initial aqueous solution, acidified with HCl, is complexed with O,O-diethyldithiophosphate and Triton X-100 is added as a surfactant. After phase separation at 40°C based on cloud point of the mixture and dilution of the surfactant-rich phase with methanol, the enriched analyte is determined by flame atomic absorption spectrometry using conventional nebulization and the analytical wavelength used is 324.8 nm. The variables affecting the complexation and extraction steps were optimized. Under optimum conditions, preconcentration of 10 ml of sample in the presence of 0.1% (v/v) Triton X-100 permitted the detection of 0.94 ng ml⁻¹ of Cu. Analytical graphs were rectilinear in the concentration range of 5-200 ng ml⁻¹ and relative standard deviations were lower than 3%. The method affords recoveries in the range 97-101%. The method was successfully applied to the determination of Cu in drinking and rainwater, serum and human hair samples.     

Cloud point extraction of iron(III) and vanadium(V) using 8-quinolinol derivatives and Triton X-100 and determination of 10(-7)moldm(-3) level iron(III) in riverine water reference by a graphite furnace atomic absorption spectroscopy

The cloud point extraction behavior of iron(III) and vanadium(V) using 8-quinolinol derivatives (HA) such as 8-quinolinol (HQ), 2-methyl-8-quinolinol (HMQ), 5-butyloxymethyl-8-quinolinol (HO₄Q), 5-hexyloxymethyl-8-quinolinol (HO₆Q), and 2-methyl-5-octyloxymethyl-8-quinolinol (HMO₈Q) and Triton X-100 solution was investigated. Iron(III) was extracted with HA and 4% (v/v) Triton X-100 in the pH range of 1.70-5.44. Above pH 4.0, more than 95% of iron(III) was extracted with HQ, HMQ, and HMO₈Q. Vanadium(V) was also extracted with HA and 4% (v/v) Triton X-100 in the pH range of 2.07-5.00, and the extractability increased in the following order of HMQ < HQ < HO₄Q < HO₆Q. The cloud point extraction was applied to the determination of iron(III) in the riverine water reference by a graphite furnace atomic absorption spectroscopy. When 1.25 × 10⁻³ M HMQ and 1% (v/v) Triton X-100 were used, the found values showed a good agreement with the certified ones within the 2% of the R.S.D. Moreover, the effect of an alkyl group on the solubility of 5-alkyloxymethyl-8-quinolinol and 2-methyl-5-alkyloxymethyl-8-quinolinol in 4% (v/v) Triton X-100 at 25 °C was also investigated.