News in Brief

About 200 billion yuan (24.3 billion US dollars) of investment was spent in infrastructure projects in west China region in 2003, occupying 55.2 percent of the country's total annual investment to the region. According to a leading group conducting the west development strategy, China plans to invest 363.5 billion yuan (44 billion US dollars) to the west in 2003, including 76 key projects.     

Problems in Chemistry

利用数学方法解决化学问题是化学及相关专业学生必备的技能之一。作者Daley,H.O.针对这一需要,为大学学习普通化学的学生编写了这本习题集。通过解题学生可以检验自己对化学原理掌握的深浅程度。     

Evidence for dose rate effect in gamma-radiolysis—II. Methylmethoxyacetate in 2,3-dimethylbutane and in cyclohexane

Solutions of 2,3-dimethylbutane (DMB) and cyclohexane containing a captodative solute, methylmethoxyacetate (MMA), were irradiated (continuous wave). Alkane dimeric products were analysed by capillary gas chromatography. G-yields were estimated as a function of the concentration of the captodative solute. By reaction with alkyl radicals, the captodative solute gives the free radical stabilized by the captodative effect. Combination reaction of this radical with itself or with alkyl radicals gives solute or mixed dimer which were also analysed. A large intensity effect was noticed, as was seen in the solutions of n-hexane-MMA. Dose effect was definitely rejected.     

Zur Kupier- und Molybd?nbestimmung in Mineralien, in Molybd?nkonzentraten und in Ferromolybd?n

Ohne Zusammenfassung     

Tritium in surface waters, tap water and in precipitation in Poland during the 1994–1999 period

Concentrations of tritium in environmental waters (precipitation, rivers, lakes, tap water) have been determined using electrolytic enrichment and liquid scintillation counting. In waters of big rivers (the Vistula and the Odra rivers), lakes and tap water the annual average concentrations were similar to each other being from 1.4 to 1.9 Bq·dm^-3. These concentrations were similar to those in the precipitation in which they ranged from 1.7 to 2.2 Bq·dm^-3. The lowest tritium concentrations were found in waters of the Seashore Region rivers (average for 1994–1999 was 1.1 Bq·dm^-3). The tritium concentrations in surface waters and in precipitation are still higher than that of natural level. The data obtained show that tritium concentration in the water of rivers might depend on the size of drainage area. The observed seasonal variations of tritium concentration in the precipitation collected in Warsaw and at the Mount Sniezka indicate the stratospheric source of tritium. It was found that about 30% of tritium deposited with precipitation is removed to the Baltic Sea with river waters.     

Radon concentrations in kindergartens and schools in two cities: Kalisz and Ostrów Wielkopolski in Poland

Plastic PicoRad detectors with activated charcoal have been used for radon monitoring in local kindergartens and schools in two cities, Kalisz and Ostrów Wielkopolski, in the region of Greater Poland. Detectors were exposed for a standard time of 48 h during the autumn and winter of 2011 in 103 rooms (Kalisz) and 55 rooms (Ostrów Wlkp), respectively. The detectors were calibrated in the certified radon chamber of the Central Laboratory for Radiological Protection in Warsaw, Poland. The arithmetic and geometric means of indoor radon concentrations in the examined rooms were 46.0 and 30.3 Bq/m³ for Kalisz and 48.9 and 29.8 Bq/m³ for Ostrów Wlkp, respectively. The measured levels of the indoor radon concentrations were relatively low, since the main source of indoor radon for these low storey (max. three storeys) buildings is radon escaping from the underlying soil with a low ²²⁶Ra concentration (~15 Bq/m³). Therefore, the calculated annual effective doses from that source for the children in Kalisz and Ostrów Wlkp were also low 0.35 mSv.     

Elements in the Sera of Preschool Children Living in Central Taiwan

This study assessed elemental concentrations in the serum of 154 preschool children in central Taiwan via instrumental neutron activation analysis （INAA）. A total of eight elements, Br, C1, Fe, Na, Rb, Sc, Se and Zn of sera for Taiwanese preschool children living at four residential areas： Taichung city, Taichung urban townships and in a remote area inhabited by two groups of aborigines, Atayal and Bunun were determined. Standard reference materials （tomato leaves, NIST-SRM 1570a, and lichen, IAEA-336） were used as quality control standards to crosscheck the accuracy. Residential area, socioeconomic status and gender were shown to significantly influence serum levels of the eight trace elements. Statistical analysis revealed several different gender patterns via the two-tailed student＇s test. A quantified index of agreement （AT） was used to classify these elements. Small AT indicated a close consistency, while large AT indicated a larger fluctuation, or less agreement, such that the correlation between the elements could be interpreted using a series of quantified indices at the serum levels of preschool children.     

一种罗丹明衍生物的合成及其对三价金属离子(Fe~(3+)、Cr~(3+)和Al~(3+))的识别

三价金属离子(Cr~(3+)、Fe~(3+)和Al~(3+))与人体健康密切相关。目前,检测Cr~(3+)、Fe~(3+)和Al~(3+)需要采用不同的荧光探针,增加了检测成本和检测时间。发展能够同时检测Cr~(3+)、Fe~(3+)和Al~(3+)的高灵敏度和强抗干扰能力的荧光探针具有非常重要的意义。本文以罗丹明B为原料,合成和表征了一种罗丹明类荧光增强型探针(P),并研究了其光谱性质。研究表明,在V(甲醇)∶V(水)=9∶1体系中对三价金属离子Fe~(3+)、Cr~(3+)和Al~(3+)具有较高的选择性,不受其它二价金属离子及一价金属离子的影响,抗干扰能力强。同时,探针P对三价金属离子具有较高的灵敏度,对Cr~(3+)、Al~(3+)和Fe~(3+)的检测限分别为3.0×10~(-4)、2.7×10~(-4)和1.0×10~(-4)mol/L,表明其可用于Cr~(3+)、Al~(3+)和Fe~(3+)的检测。     

A Highly Selective Fluorescent Chemosensor for Cu2+

A new Zn²⁺ probe L2-Zn(L2=naphthofuran carbonylhydrazone derivant) was synthesized as a fluorescence chemosensor for Cu²⁺, by which Cu²⁺ ion could be detected with high selectivity and sensitivity in a wide pH range via a displacement “turn-off” signaling strategy. Whereas the coordination between Zn²⁺ and L2 resulted in a considerable enhancement of typical luminescence of a naphthalofuran group in complex L2-Zn, the addition of Cu²⁺ ion led to a dramatic decrease in the emission intensity of probe L2-Zn at about 503 nm(excitation at 423 nm). The competitive fluorescent experiments showed that other metal ions, such as Hg²⁺, Fe³⁺, Ag⁺, Ca²⁺, Co²⁺, Ni²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Cr³⁺ and Mg²⁺ could not impact the detection of Cu²⁺. The detection limit of the novel probe L2-Zn for Cu²⁺ ion was as low as 2.3×10^-7 mol/L, which is far lower than the guideline value of 1.6×10^-5 mol/L of the United States Environmental Protection Agency.     

新型水溶性罗丹明类荧光探针的合成及其对游离3价金属离子的识别

以罗丹明B为原料,设计合成一种新型水溶性荧光探针(L),并对其进行表征和光学性能研究.结果表明,探针L能在纯水体系(TRIS,pH=7.4)中快速识别游离M3+(Cr3+、Al3+、Fe3+)金属离子,为荧光增强型探针,具有灵敏度高、抗干扰能力强的特点.探针L对Cr3+、Al3+、Fe3+的荧光检测限分别为1.57×1...     

A New Tetrasubstituted Imidazole Based Difunctional Probe for UV-spectrophotometric and Fluorometric Detecting of Fe3+ Ion in Aqueous Solution

Two new compounds,4-(2-bromophenxl-4,5-diphenyl-imidazol-1-yl)ani 1 ine(probe 1)and 4-[2,4,5-tris(4-bromopheny1)-1H-imidazol-1-y1]aniline(probe 2),were synthesized via a soft and high-efficiency one-pot microwave-assisted method under solvent-free conditions.Their sensing to different metal ions was detected by UV spectrophotometry and fluorescence spectrometry.Probe 2 revealed highly selective and sensitive UV and fluorescence response to Fe^3+ion.Upon the addition of Fe^3+ion,probe 2 showed obvious color change of the solution,conspicuous absorbance enhancement and relatively quick fluorescence quenching.The detection limit for Fe^3+ion was respectively calculated to be 0.72μmol/L(fluorescent detection)and 0.48μmol/L(UV-spectnim detection).Also,probe 2 was bound by Fe^3+ion to tonn a 1:1 complex.Moreover,preliminary application of probe 2 tor detecting Fe^3+ion in aqueous solution was attempted,and satisfying results were obtained.     

一种具有荧光性质的阳离子Ga⁃MOF用于Fe3+和硝基化合物识别

通过溶剂热法合成了一种新型阳离子镓金属-有机框架Ga-MOF, 其化学式为[Ga₃O(H₂O)₃(TCA)₂]·NO₃·6DMF·2H₂O(JOU-27, H₃TCA=4,4′,4″-三苯胺三羧酸). 结构分析表明, JOU-27是基于氧心三核镓簇的三维微孔结构. 由于荧光配体H₃TCA的引入, JOU-27具有强的荧光发射强度, 因此可用于检测Fe³⁺离子和硝基芳香族化合物. 结果表明, 其对Fe³⁺的检出限低至2.22×10^-6 mol/L(Stern-Volmer常数K_SV=52823 L/mol); 当硝基苯(NB)浓度仅为3.27×10^-3 mol/L时, 荧光猝灭效率可达91%. 进一步的研究表明, JOU-27的猝灭性能可能与荧光共振能量转移(FRET)效应、 激发光吸收竞争以及骨架激发态与硝基芳烃化合物之间的电子转移有关.     

沉淀聚合制备荧光聚脲微球及Fe3+检测

以异氟尔酮二异氰酸酯为单体, 以氨基功能化的1.8-萘二甲酰亚胺(AABD)为荧光基团, 在水/丙酮质量比为3/7的混合溶剂中, 通过沉淀聚合制备了表面洁净的高度单分散荧光聚脲微球(FPU). 通过FTIR及¹H NMR对AABD及FPU的化学结构进行了表征; 通过UV-Vis光谱确定FPU中嵌入的AABD荧光单元的含量; 通过荧光光谱研究了FPU固体粉末分散在水中及溶解在N-甲基吡咯烷酮中的荧光特性以及FPU分散在不同Fe³⁺浓度水溶液中的荧光变化. 结果表明, FPU的平均粒径(D_n)为5.24 μm, 粒径分布(D_w/D_n)为1.004, 具有强烈的绿色荧光(激发波长为420 nm, 最大发射波长为522 nm); FPU分散在水中不发生荧光自猝灭, 其荧光强度随着Fe³⁺浓度的增加(10^-4 ~10^-3 mol/L)呈线性降低.     

含磷酰杂菲侧基的苯乙烯衍生物聚集诱导发光特性及其在过渡金属离子检测中的应用

以2-(6-氧化-6-氢-二苯基(c,e)<1,2>氧杂磷酰基)-1,4-二羟基苯(ODOPB) 为中心结构单元, 通过两步酯化反应, 在两侧分别引入4-戊氧基苯甲酰基和4-乙烯基苯甲酰基, 得到苯乙烯衍生物(MED).由于磷酰杂菲基团的大π共轭结构和极性共同作用, 使得形成聚集体后分子内转动受到限制, 降低了非辐射去活效率, 使 MED在达到一定聚集程度时, 荧光强度成倍增加, 呈现出聚集诱导发光增强(AIEE) 特性. 同时, Pt²⁺, Ru³⁺, Fe³⁺的加入对MED有显著的猝灭效果; 而Fe²⁺只是在形成聚集体过程中才有猝灭效果.     

一种新型比色荧光双通道水相检测氰根离子的化学传感器

合成了一种新型的,能在含水介质中比色荧光双通道单一选择性识别CN^-的传感器分子1-羟基萘甲叉酰肼乙基-3-羟基萘甲叉酰肼甲基苯并咪唑溴鎓盐(J1)。 在J1的DMSO/H₂O (体积比3:2)HEPES 的缓冲体系(pH=7.2)中分别加入F^-、Cl^-、Br^-、I^-、AcO^-、HSO₄^-、ClO₄^-、H₂PO₄^-、SCN^-和CN^-等阴离子后,只有CN^-的加入会使得溶液颜色发生明显的变化,由无色变为深黄色。 相应地在J1的DMSO/H₂O (体积比4:1)HEPES的缓冲体系(pH=7.2)中加入CN^-,溶液发出明亮的黄色荧光。 这一识别过程,不会受到其它阴离子的干扰。 紫外-可见光谱的最低检测限为1.57×10^-7 mol/L,检测线性范围为3.875×10^-4~2.15×10^-2 mol/L。 荧光光谱的最低检测限为4.63×10^-6 mol/L,检测线性范围为0.8×10^-4~1.60×10^-3 mol/L。 此结果表明,J1是一种良好的用于识别 CN^-的化学传感器,在含水介质中对CN^-具有选择性好、灵敏度高以及抗干扰性强的识别性能。 与此同时,基于J1对于CN^-的高选择性识别我们制备了CN^-的检测试纸,该试纸能够方便、快捷、准确地检测水中的CN^-。     

11-Mercaptoundecanoic acid functionalized gold nanoclusters as fluorescent probes for the sensitive detection of Cu2+ and Fe3+ ions

Metal ions are physiologically essential,but excessive metal ions may cause severe risk to plants and animals.Here,we prepared gold nanoclusters(Au NCs) protected by 11-mercaptoundecanoic acid(11-MUA),which have excellent fluorescence properties for the detection of metal ions.The results showed that the copper ions(Cu~(2+)) and iron ions(Fe~(3+)) in the solution have obvious quenching effect on the fluorescence intensity of Au NCs.The detection range of Fe~(3+) was 0.8–4.5 mmol/L(R~2= 0.992) and 4.5–11.0 mmol/L(R~2= 0.997).And Cu~(2+) has a lower linear range(0.1–1.0 mmol/L,R2= 0.993).When EDTA was added into the reaction system,it was observed that the quenching effect of Cu~(2+) and Fe~(3+)on Au NCs showed different phenomenon.Then,the effect of metal ions on the fluorescence of Au NCs was investigated.The selective detection of Cu~(2+) was achieved by EDTA masking of Fe~(3+).In addition,we realized the metal ions detection application of Au NCs in the serum     

氯化钾介质中铈(Ⅲ)的荧光特性及应用研究

Ce³⁺在pH<6.2的KCl介质中受252.4nm的紫外光激发时,发射出的353.8nm荧光可用于痕量铈的测定.在pH5～6时,用Al₂(SO₄)₃可消除Fe³⁺的干扰.在0～3.0×10^-6mol/L范围内,荧光强度与Ce³⁺的浓度遵守ΔF=2.37×10⁶C-0.001方程(n=10,r=0.9999),检测限为6.0×10^-9mol/L.用于GWB07103(GSR-1)岩石成分分析的回收率为95.0％～103.2％,变异系数是4.18％(n=10);用于水系沉积物和土壤标准物质中铈含量分析,结果与标准值无显著差异.