离子选择性电极测定岩石矿物中的氯

用离子选择性电极法测岩石中的Ｃｌ＾－，相对误差不大于５．０％，处理成溶液后的检出限为１．５＊１０＾－６ｇ／ｍＬ。     

自动电位滴定快速测定84消毒液中的有效氯含量

During the outbreak of novel coronavirus pneumonia, 84 Disinfectant has been widely used. It is very important to determine the available chlorine content in 84 Disinfectant. A new method to rapidly determine the available chlorine content in 84 Disinfectant by automatic potentiometric titration was established. Statistically, there is no significant difference in results between automatic potentiometric titration and manual titration. Combined the principles of analytical chemistry and the application to the determination of anti-epidemic material, this experiment has theoretical and practical significance, and can be used as an experiment in analytical chemistry laboratory for sophomore students.     

Ab initio studies of CIO, reactions: prediction of the rate constants of CIO + NO for the forward and reverse processes.

The mechanisms for ClO+NO and its reverse reactions were investigated by means of ab initio molecular orbital and statistical theory calculations. The species involved were optimized at the B3LYP/6-311 +G(3df) level, and their energies were refined at the CCSD(T)/6-311+ G(3df)//B3LYP/6-311 + G(3df) level. Five isomers and the transition states among them were located. The relative stability of these isomers is ClNO2 > cis-ClONO > trans-ClONO > cis-OClNO>trans-OClNO. The heats of formation of the three most-stable isomers were predicted using isodesmic reactions by different methods. The predicted bimolecular reaction rate constant shows that, below 100 atm, the formation of Cl+NO2 is dominant and pressure-independent. The total rate constant can be expressed as: k(ClO+NO)= 1.43 x 10(-9)T(-083)exp(92/ T) cm3 molecule(-1)s(-1) in the temperature range of 200-1000 K, in close agreement with experimental data. For the reverse reaction, Cl+NO2-->ClNO2 and ClONO (cis and trans isomers), the sum of the predicted rate constants for the formation of the three isomers and their relative yields also reproduce the experimental data well. The predicted total third-order rate constants in the temperature range of 200-1000 K can be represented by: k0(He) = 4.89 x 10(-6)T(-5.85) exp(-796/T) cm6 molecule(-1)s(-1) and k0(N2) =5.72 x 10(-15)T(-5.80) exp(-814/T) cm6 molecule(-1)s(-1). The predicted high- and low-pressure limit decomposition rates of CINO2 in Ar in the temperature range 400-1500 K can be expressed, respectively, by: k-(ClNO2) = 7.25 x 10(19)T(-1.89) exp(-16875/T) s(-1) and kd(ClNO2) = 2.51 x 10(38)T(-6.8) exp(-18409/T) cm3 molecule(-1) s(-1). The value of k0(ClNO2) is also in reasonable agreement with available experimental data.     

Structural characterization of 5,6-dichlorotetradecanoic acid, an isolated metabolite of 9,10-dichlorooctadecanoic acid, by studying picolinyl esters, pyrrolidides and methyl esters with electron ionization mass spectrometry

A method is presented for identification of positional isomers of dichlorinated fatty acids, based on derivatization to picolinyl esters prior to gas chromatographic/mass spectrometric analysis in the electron ionization mode. The mass spectra of the picolinyl esters showed structure-specific fragmentation patterns. By using the picolinyl ester, 5,6-dichlorotetradecanoic acid was identified as a metabolite from a cell-culture medium obtained by culturing human cell lines in media supplemented with threo-9,10-dichlorooctadecanoic acid. This indicates that dichlorinated fatty acids are degraded by beta-oxidation. It is also possible to locate tentatively the position of chlorine atoms in 5,6-dichlorotetradecanoic acid as its methyl ester or pyrrolidide.     

Chlorine degradation of polyether-based polyurethane

The tensile properties of polyether-based polyurethane (PU) filaments decrease with increasing chlorine concentrations as well as with treatment times. Fourier transform infrared (FTIR) results show the formation of quinoid, azo, and aldehyde groups in the chlorine-treated PU, and increased hydrogen bonding between the C O C in the soft segment and the N H in the hard segments. A breakdown mechanism involving chain cleavages along the ether linkages in the soft segments as well as at the urethane linkages of the hard–soft segment interfaces is proposed. Chlorine-treated PU showed increased solubility in tetrahydrofuran (THF). The molecular weight data of the THF-soluble portion of treated PU also support the proposed locations of chain scissions. The increased soft segment T_g and T_m with increasing chlorine concentrations are results of increased phase-mixing and hydrogen bonding. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3263–3273, 1997     

ChemInform Abstract: Ring Structure Formation in Transition-Metal Nitrido Chlorides by Donor—Acceptor Formation.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

一种检测麻痹性贝毒的高效液相色谱法

提出了一种利用高效液相色谱法同时分析麻痹性贝毒GTX组分和NEO/dcSTX/STX组分的方法。本法仅使用了一种缓冲溶液作为流动相,在InertsilC8-3色谱柱(250mm×4.6mm,5μm)上,采用梯度改变乙腈在流动相中的比例和流速,一次进样可同时定性及定量待测试样中的上述全部毒素组分。该缓冲溶液为9.0mmol/L磷酸铵缓冲溶液(pH=7.2),含有2.8mmol/L的庚烷磺酸钠。色谱分离过程首先以纯水相缓冲溶液进行等度洗脱,在16.5~19min向流动相中梯度加入1.5%的乙腈,加速GTX3和GCX2的洗脱,以避免GTX2的色谱峰与乙腈的溶剂峰重叠,随后从19min开始加大流动相中乙腈的比例为8.5%,以缩短边缘组分的保留时间。荧光检测器的激发波长和发射波长分别设为330nm和390nm。用本方法分析染毒的华贵栉孔扇贝和近江牡蛎,证实了本方法对PSP毒素具有良好的分析测定效果。