离子交换树脂-固相萃取富集-电感耦合等离子体光谱法测定水中重金属元素

建立了离子交换树脂-固相萃取富集-电感耦合等离子体光谱(ICP-AES)联用测定水中的重金属元素Zn,Mn,Cu,Co,Ni,Cd,Pb的方法。实验采用Dowex50WX8强酸型阳离子交换树脂,通过优化富集分离条件和排除共存离子的干扰,最终确定最佳的样品pH,样品流速,洗脱液种类和浓度,样品体积分别为3.0~4.0,3.0 mL·min-1,3.0 mol·L-1 HNO₃,200 mL。方法中各元素的检出限和定量限范围分别为0.09~0.45和0.31~1.50 μg·L-1,加标回收率和相对标准偏差RSD(n=6)分别为95.3%～104.2%和1.25%～4.12%。采用该方法测定不同地区的样品,并与直接采用ICP-MS法进行对比,其测定结果基本吻合。实验表明该方法的检出限,定量限可以满足水中重金属元素Zn,Mn,Cu,Co,Ni,Cd,Pb的检测要求,准确性和精密度好,结果可靠,适用于测定水中Zn,Mn,Cu,Co,Ni,Cd,Pb。     

FAAS法测定苦杏仁和甜杏仁中的13种金属元素

采用硝酸、高氯酸(V/V=4/1)常压微沸条件下消解苦杏仁和甜杏仁样品,火焰原子吸收法测定苦杏仁和甜杏仁中的金属元素:Mn、Ca、K、Mg、Na、Zn、Cu、Fe、Co、Cd、Ni、Pb、Cr的含量,研究了测定不同元素仪器的最佳工作条件、方法的准确度和精密度.结果表明:苦杏仁中Mn、Ca、K、Mg、Na、Zn、Cu、Fe、Co、Cd、Ni和Pb的含量分别为11.756,1614.167,5153.191,238.478,97.668,274.836,16.844,546.316,9.952,3.474,5.979,2.143μg·g-1Cr未检出,方法回收率(n=9)在97.32%-102.57%之间,RSD(n=9)在0.14%-2.22%之间;甜杏仁中Mn、Ca、K、Mg、Ni、Zn、Cu、Fe、Co、Cd、Ni和Pb的含量分别为6.622,1937.503,8663.824,216.956,257.546,77.961,12.483,372.183,7.990,3.666,2.268,3.214μg·g-1Cr未检出,方法回收率(n=9)在97.23%-102.43%之间,RSD(n=9)在0.47%-2.14%之间.该法快速,简单,准确度和精密度均较高,能达到分析要求.     

FAAS测定半夏12种金属元素的含量

采用先灰化、再用体积比为4:1的HNO_3-HClO_4混酸常压微沸条件下消解半夏样品,火焰原子吸收光谱法测定半夏中的金属元素Na、K、Ca、Mg、Fe、Cu、Zn、Co、Mn、Pb、Ni、Cd含量,研究了测定不同元素的仪器最佳工作条件,并作了方法的准确性和精密度考察。结果表明,半夏中Na、K、Ca、Mg、Fe、Cu、Zn、Co、Mn、Pb、Ni的含量分别为1172.09,1000.13,11098.56,1690.48,103.93,9.35,56.75,88.39,10.70,8.79,70.62μg/g,Cd未测出。方法的加标回收率为96.45%—104.5%,精密度RSD(n=9)为0.34%—2.7%。测定方法简单易行、快速、准确,结果令人满意。     

萃取分离-电感耦合等离子体质谱法测定高纯铝中的杂质元素

采用APDC-MIBK萃取分离铝,电感耦合等离子体质谱(ICP-MS)法同时测定高纯铝中Co,Ni,Cu,Mo,Cd,Pb和Bi。详细地讨论了仪器工作参数,内标元素,分离、富集条件,样品基体的干扰,确定了实验的最佳测定条件。结果表明,方法的检出限为0.011～0.052 μg·L-1,回收率为92.2%～103.0%,相对标准偏差(RSD)小于2.3%。方法准确、快速、简便,应用于高纯铝中Co,Ni,Cu,Mo,Cd,Pb和Bi等杂质元素的测定,结果满意。     

FAAS法测定地石榴中12种金属元素

采用浓硝酸∶高氯酸(4+1)常压微沸条件下消解地石榴样品,应用火焰原子吸收光谱法测定了地石榴中的金属元素Na、K、Mg、Ca、Fe、Co、Ni、Cu、Zn、Mn、Cd、Pb含量,研究了测定不同元素的仪器最佳工作条件、方法的准确性和精密度。结果表明,地石榴中Na、K、Mg、Ca、Fe、Cu、Zn、Mn、Cd含量分别为33.88,3444.54,328.54,1924.76,56.65,1.88,2.97,1.59,2.99mg.100g-1,Co、Ni、Pb未检出。方法的加标回收率为98.16%—103.6%,相对标准偏差(n=9)为0.21%—2.22%。测定方法简单易行,方便快捷,结果令人满意。     

FAAS法测定不同产地油菜花粉中13种金属元素含量

采用先灰化、再经硝酸-高氯酸(V∶V=4∶1)常压微沸条件下消化油菜花粉样品,应用火焰原子吸收法测定不同产地油菜花粉中的金属元素K,Na,Ca,Mg,Fe,Co,Ni,Cu,Zn,Mn,Cd,Cr和Pb的含量。研究了测定不同元素的仪器最佳工作条件,并作了方法的准确性和精密度的考察。结果表明：山丹和景泰油菜花粉中K,Na,Ca,Mg,Fe,Cu,Zn和Mn的含量分别为4 248.00,75.77,312.10,856.61,599.53,8.78,27.82,22.54 μg·g-1和7 585.75,242.56,287.88,699.43,1 020.65,10.25,40.44,30.97 μg·g-1。Co,Ni,Cr,Cd和Pb未检出。加标回收率为95.22%～105.49%,相对标准差(n=9)为0.30% ～5.00%。测定方法简单易行,方便快捷。     

火焰原子吸收法测定栽培小茴香中13种金属元素含量

采用先灰化、再用硝酸-高氯酸(φ 4∶1)常压微沸条件下消解小茴香样品,应用火焰原子吸收法测定栽培小茴香中的金属元素Na,K,Mg,Ca,Cu,Zn,Mn,Fe,Co,Ni,Cd,Cr和Pb含量,研究了测定不同元素的仪器最佳工作条件,并作了方法的准确性和精密度考察。结果表明,栽培小茴香中Na,K,Mg,Ca,Mn,Fe,Cu,Zn和Pb含量分别为1 508.7,27 653.0,2 036.0,4 848.1,24.8,323.5,15.2,23.7和10.8 μg·g-1;Ni,Co,Cd和Cr未检出。方法的加标回收率为97.45%～102.50%, 相对标准偏差(n=9)为0.34%～2.77%。测定方法简单易行,方便快捷,结果令人满意。     

火焰原子吸收法测定夏枯草、桑叶、野菊花中十种微量元素

湿法消化样品 ,火焰原子吸收法测定三种草药中的 Mg、Ca、Zn、Mn、Co、Ni、Pb、Cd、Fe、Cu等 10种微量元素。回收率分别为 97.7%— 10 1.5 % ;96 .0 %— 10 5 .1% ;97.1%— 10 3.6 % ,相对标准偏差为 1.6 %—4 .5 % ;1.7%— 4 .7% ;1.7%— 4 .6 %。结果表明 ,三种草药均含有丰富的微量元素如 Mg、Ca、Zn、Mn、Fe、Cu等 ;为原料的开发和应用提供有效数据。     

离子交换-原子吸收法测定水中ppb级痕量元素

本试验考查了四种不同树脂的回收,发现国产122螯合型阳离子树脂(水阳酸-苯酚-甲醛)是用于水中痕量元素分析的一种理想材料,在选定的pH,交换柱高等的条件下,122树脂同国外广泛选用的chelex-100树脂相似,具有选择性好,分配系数大,交换速度快,膨胀倍数小的特点,淋洗曲线证明:除铁外,各试验元素洗脱集中,回收完全,没有拖尾现象,此外,122树脂交换容量大(47.84毫克当量/克)有足够大的“始漏量”,可使水样中被研究元素得到10—40倍以上富集,实验证明,122氢型树脂的洗脱过程就是再生过程,无需转型再生,操作简便,快速,优于其它树脂,本文对共存元素的干扰及其干扰的消除进行了详细的研究,在本测定条件下,各类水样经分离-富集-洗脱后,可用火焰原子吸收连续测定ppb级Ca,Pb,Zn,Cd,Mn,Ni,Co,Fe方法实际测定限优于1ppb,各元素的标准偏差分别为:Cu 2.42%,Pb 1.06%,Zn 4.74%,Cd 2.66%,Mn 2.23%,Ni 2.95%,Co 1.16%,Fe9.30%     

火焰原子吸收光谱法测定中草药剑花中的8种微量元素

比较了干灰化法和湿法处理样品对测定结果的影响,用火焰原子吸收光谱法对剑花中Cu,Mn,Fe,Zn,Ni,Co,Cd和Pb八种微量元素进行分析测定。结果显示,用HNO₃-HClO₄(5∶1)混酸作消化液处理样品,精密度和回收率较好;在选定的实验条件下,剑花中各元素间相互不干扰,可在一份样品液中进行8种元素的分别测定;剑花中含有较丰富的Fe,Mn和Zn,以及Cu和Ni,未检出Co和Cd,但检出了有毒金属Pb。方法的检出限均小于0.086 μg·mL-1,RSD≤8.37%(n=8),加标回收率79.69%～118.6%。     

Solution absorption and luminescence studies of tetraphenylboron, -carbon, -silicon, -germanium, -tin, -lead, -phosphorus, -arsenic,and -antimony

The lowest absorption band of the tetraphenyl compounds resembles that of the lowest absorption band of benzene with the following difference. In benzene the electronic origin is strictly forbidden, and all intensity is associated with a symmetric progression built on one mode of asymmetric vibration. In the tetraphenyl compounds the intensity associated with the asymmetric vibration is relatively unaffected; however, there is increasing intensity associated with the electronic origin and a symmetric progression built on it along the series

$\text{φ}{}_4\text{Pb}\text{< φ}{}_4\text{Sn}\text{< φ}{}_4\text{Ge}\text{< φ}{}_4\text{Si}\text{< φ}{}_4\text{C}\text{? φ}{}_4\text{B}{}^{\mathrm{?}}\text{< φ}{}_4\text{Sb}{}^{\mathrm{+}}\text{< φ}{}_4\text{As}{}^{\mathrm{+}}\text{< φ}{}_4\text{P}{}^{\mathrm{+}}$

. For the cations it is the electronic origin and the progression built on it that are the primary source of intensity. This effect is attributed to an inductive perturbation. A similar effect is observed in the fluorescence spectrum. In phosphorescence, the relative enhancement of the electronic origin and the progression built on it is far less marked. The phosphorescence emission of φ₄Pb and φ₄Sb⁺ are red shifted from the others by ～0.5 eV, an effect attributed to formation of a triplet excimer. Increasing spin-orbit coupling in the triplet due to a heavy atom effect can be seen in the decreasing phosphorescence lifetime (range 4 sec to 4 msec) and decreasing ratio of $\text{φ}{}_{\mathrm{f}}\text{φ}{}_{\mathrm{p}}$ (fluorescence to phosphorescence quantum yields) in the order

$\text{φ}{}_4\text{C}\text{> φ}{}_4\text{B}\text{> φ}{}_4\text{Si}\text{> φ}{}_4\text{P}{}^{\mathrm{+}}\text{> φ}{}_4\text{Ge}\text{> φ}{}_4\text{As}{}^{\mathrm{+}}\text{> φ}{}_4\text{Sn}$

In all cases nonexponential decay of phosphorescence is observed.     

Mesomorphic, dielectric, and optical properties of fluorosubstituted biphenyls, terphenyls, and quaterphenyls

Compounds with moderate and large negative dielectric anisotropy (Δɛ) are very attractive liquid crystal (LC) for vertical alignment mode (VA). Materials with such properties can be achieved by lateral substitution of a polar group into a mesogenic molecule. We synthesized some new LC materials with a negative value of Δɛ, a moderately high birefringence (Δn), and a low viscosity. The mesomorphic and physical behaviour of the novel biphenyls, terphenyls and quaterphenyls fluorosubstituted in the rigid core and also with fluorinated alkyl and alkoxy chains are investigated. The prepared series of four LC compounds are promising for new LC mixtures for various applications. Examples of nematic mixtures with Δɛ∼−3.25 will be presented.     

Bits,time, carriers,and matter

The formal structure of quantum information theory is based on the well-founded concepts and postulates of quantum mechanics. In the present contribution, I am inverting the usual approach presented in textbooks by beginning with the use of bit states as basic and fundamental units of information and establish a dynamical map for them. The condition of reversibility, imposed on an ordered sequence of actions operating on a bit state, introduces, by necessity, the unitarity property of actions. I also verify that the uniformity of time, as a parameter for ordering events, is due to the admission of a composition law for the actions. In the limit of infinitesimal intervals between actions, a reversible and linear equation arises for the dynamical changes in time of a qubit (superposition of bit states). The admission that a bit of information is stored or carried by a massive particle necessarily leads to the Schrödinger–Pauli equation (SPE); the bit is associated to a spin 1/2. Within this approach, I verify that the particle dynamical equation becomes “enslaved” by the spin dynamics. In other words, the bit (or spin) precedes in status the particle dynamical evolution, being at the root of the quantum character of the standard Schr¨odinger equation, even when spin and spatial degrees of freedom are uncoupled.     

Walks,walls, wetting,and melting

New results concerning the statistics of, in particular,p random walkers on a line whose paths do not cross are reported, extended, and interpreted. A general mechanism yielding phase transitions in one-dimensional or linear systems is recalled and applied to various wetting and melting phenomena in (d=2)-dimensional systems, including fluid films and p×1 commensurate adsorbed phases, in which interfaces and domain walls can be modelled by noncrossing walks. The heuristic concept of an effective force between a walk and a rigid wall, and hence between interfaces and walls and between interfaces, is expounded and applied to wetting in an external field, to the behavior of the two-point correlations of a two-dimensional Ising model belowT _c and in a field, and to the character of commensurate-incommensurate transitions ford=2 (recapturing recent results by various workers). Applications of random walk ideas to three-dimensional problems are illustrated in connection with melting in a lipid membrane model.Based on the Boltzmann Medalist address presented at the 15th IUPAP International Conference on Thermodynamics and Statistical Mechanics, Edinburgh, July 1983.     

Einstein,Podolsky, Rosen,and Shannon

The Einstein–Podolsky–Rosen paradox (1935) is reexamined in the light of Shannons information theory (1984). The EPR argument did not take into account that the observers information was localized, like any other physical object.Dedicated to the memory of James T. Cushing     

Quarks,diquarks, tetraquarks,and pentaquarks

A particle about 50% more massive than a proton, with positive charge, positive strangeness and positive baryon number, has been claimed in several experiments. Such a particle cannot be made from three quarks; its minimal configuration requires four quarks and an antiquark and it became known as a ‘pentaquark’. This article summarizes the evidence and concentrates on the theoretical interest that it has excited into the nature of correlations among quarks and antiquarks in the strong interaction limit of QCD.