示波极谱测定空气中微量甲胺磷

提出了间接不波极谱测定微量甲胺磷的方法.研究在碱性条件下.甲胺磷水解生成甲硫酸钠,甲硫酸钠与亚硝酸作用生成亚硝基化合物,在Hg(Ⅱ)作用下水解,释放出NO_2~-.继与对氨基苯磺酰胺和8-羟基喹啉形成偶氮化合物.对其极谱行为进行研究.方法灵敏度高,对甲胺磷的选择性好,用干空气中甲胺磷测定,结果满意.     

示波极谱法测定环境样品中的微量酚

研究了酚与MBTH形成的红色偶氮化合物的极谱行为。该化合物在氢氧化钠-硼酸介质中于—0.54V(vs.SCE)处呈现一个灵敏的吸附波,波高与酚浓度在0.01～1.5μg·ml~(-1)范围内呈良好线性关系。方法简便快速,选择性较好。用于水和空气样品中的酚测定,结果满意。     

微量乐果的示波极谱测定

乐果是一种危害较大的环境污染物,常用间接比色法测定其含量,但方法灵敏度低,干扰多,不能直接测定有色、浑混样品。本文报道了根据PAR偶氮试剂在电极上有良好的还原波,参照比色手续将乐     

示波极谱法测定皮蛋中微量铅

在 pH 5 .2～ 5 .8的六次甲基四胺 HCl底液中 ,Pb2 +与邻菲啉 (phen)共存体系于- 0 .4 9V(vs .SCE)处产生一灵敏的极谱吸附波 ;铅浓度在 0 .0 15～ 0 .8μg·ml- 1范围内与峰电流呈良好线性关系 ,检出限可达 0 .0 0 8μg·ml- 1,线性回归方程为Iy=6 .80 + 12 4 .0 0Cx,相关系数为0 9973。用该方法测定了皮蛋中微量铅 ,试样加标回收率为 96 %～ 10 4 % ,相对标准偏差小于2 5 % ,结果与原子吸收吸光光度法一致。该方法准确、简便、选择性好。     

示波极谱法快速测定金属锑中的微量砷

提出了一个快速测定金属锑中微量砷的新方法，采用氢氧化钠沉淀分离基体锑与微量砷分离，并用催化示波极谱测定，效果良好。     

乙胺和二甲胺分子(n_N,3s)里德堡态共振的多光子电离

MPI质谱研究作为化学分析和研究光物理过程的工具受到广泛的重视[1－4]．REMPI的特征过程是，首先分子吸收。个光子共振激发到中间态，然后处于中间激发态的分子再吸收n个光子激发到电离连续区[5]．REMPI的谱特征可以给出中间态分布的详细信息[6]，利用REMPI过程可研究单光子跃     

乙胺和二甲胺分子(n N,3s)里德堡态共振的多光子电离

The multiphoton ionization spectra of ethylamine and dimethylamine are presented in the 400-470nm region, with resonance excitation to 3s Rydberg state. The MPI fragmentation patterns of two C2H7N isomers are readily distinguished. For ethylamine, the most prevalent fragmentation is β-Cleavage, while for dimethylamine that is H atom ejection.     

示波极谱法测定微量聚乙二醇的研究及其应用

提出了极谱法测定聚乙二醇 (PEG)的新方法。在 6× 1 0 - 3mol LHCl中 ,苯胺与亚硝酸钠反应生成重氮盐 ,该重氮盐分别与PEG 60 0、PEG 80 0、PEG 1 0 0 0、PEG 2 0 0 0反应的产物在HAc NH4 Ac缓冲溶液中各于-1 .0 6V、-0 .97V、-0 .92V、-0 .84V产生灵敏的极谱波。可用于分子量小于 2 0 0 0的PEG的定性及定量分析 ,导数波高分别与PEG 60 0浓度在 0～ 1 2g L、PEG 80 0浓度在 0～ 1 0g L、PEG 1 0 0 0浓度在 0～ 1 0g L、PEG 2 0 0 0浓度在 0～ 1 0g L范围内呈线性关系。     

Determination of Labetalol Hydrochloride in Drug Formulations by Spectrophotometry

A validated, selective and sensitive spectrophotometric method has been developed for the determination of labetalol hydrochloride in commercial dosage forms. The method is based on the coupling reaction of positive diazonium ion of 4‐aminobenzenesulfonic acid with phenolate ion of labetalol to form a colored azo compound which absorbs maximally at 395 nm. Under the optimized experimental conditions, the color is stable up to 2 h and Beer's law is obeyed in the concentration range of 0.8–17.6 μg mL^?1 with a linear regression equation of A = 4.84 × 10^?4 + 7.864 × 10^?2 C and coefficient of correlation, r = 0.9999. The molar absorptivity and Sandell's sensitivity are found to be 2.874 × 10⁴ L mol^?1 cm^?1 and 0.013 μg cm^?2 per 0.001‐absorbance unit, respectively. The limits of detection and quantitation of the proposed method are 0.08 and 0.23 μg mL^?1, respectively. The intra‐day and inter‐day precision variation and accuracy of the proposed method is acceptable with low values of standard analytical error. The recovery results obtained by the proposed method in drug formulations are acceptable with mean percent recovery ± RSD of 99.97 ± 0.52 ‐ 100.03 ± 0.63%. The results of the proposed method compared with those of Bilal's spectrophotometric method indicated excellent agreement with acceptable true bias of all samples within ± 2.0%.     

Electrochemical Reversible Reforming between Ethylamine and Acetonitrile on Heterostructured Pd-Ni(OH)2 Nanosheets

Rational design of electrocatalysts is essential to achieve desirable performance of electrochemical synthesis process. Heterostructured catalysts have thus attracted widespread attention due to their multifunctional intrinsic properties, and diverse catalytic applications with corresponding outstanding activities. Here, we report an in situ restoration strategy for the synthesis of ultrathin Pd-Ni(OH)₂ nanosheets. Such Pd-Ni(OH)₂ nanosheets exhibit excellent activity and selectivity towards reversible electrochemical reforming of ethylamine and acetonitrile. In the acetonitrile reduction process, Pd acts as reaction center, while Ni(OH)₂ provide proton hydrogen through promoting the dissociation of water. Also ethylamine oxidation process can be achieved on the surface of the heterostructured nanosheets with abundant Ni(II) defects. More importantly, an electrolytic cell driven by solar cells was successfully constructed to realize ethylamine-acetonitrile reversible reforming. This work demonstrates the importance of heterostructure engineering in the rational synthesis of multifunctional catalysts towards electrochemical synthesis of fine chemicals.     

微顺序注射-镉柱还原分光光度法测定海水中总氮

基于微顺序注射-阀上实验室,采用镉柱还原-偶氮染料染色分光光度法测定海水中总氮,对实验参数进行了优化,并进行了干扰因素实验。结果表明,海水中主要离子和盐度对本实验方法测定会产生干扰,采用一定盐度的国家标准海水作为溶剂制备系列标准溶液,可消除干扰。海水中总氮浓度在0.03~1.00 mg/L范围内与吸光度呈良好线性,线性相关系数r=0.9993;测定含氮浓度为0.2 mg/L的国家标准海水,相对标准偏差(RSD)为4.9％;方法的检出限为0.010 mg/L;样品加标回收率在99.5％~101.1％之间。经t检验分析,本方法与国标方法测定数据无显著性差异,可用于海水样品中总氮的测定。     

Polarographic Determination of Aztreonam

Abstract

The polarographic behaviour of Aztreonam is studied. In acid media, at pH values lower than 6, in differential pulse polarography a peak is observed at a potential close to ? 0.6 volts. The optimum conditions for the polarographic signal are established and the different parameters affecting the electrochemical process are studied. The relationship between peak intensity and the concentration of Aztreonam is linear for concentrations lower than 1.0 ? 10^?5 M, the detection limit being 1.4 × 10^?8 M It was observed that the presence of 1-arginine does not affect the polarographic signal of Aztreonam to any significant extent.     

Catalyst-free synthesis of 4-alkynylazobenzenes from quinols

A catalyst-free and environmently benign synthesis of highly conjugated 4-alkynylazoaromatic compounds from quinols having an alkyne is described. Formation of hydrazones by preferential condensation of quinols bearing many sensitive functional groups with mono-substituted hydrazines followed by dehydration under mild reaction conditions is the key to success of this method.     

砷铋钼三元杂多酸-羧甲基纤维素钠的极谱行为研究及微量砷的测定与应用

本文研究了砷铋钼杂多酸的极谱行为。该杂多酸络合物先在低酸度下迅速形成钼蓝,然后在0.4mol/LH_2SO_4中此杂多酸电活性络合物在滴汞电极上于—0.47(vs.SCE)产生灵敏的络合物吸附还原波。当存在CMC时灵敏度进一步提高,用二次微分极谱测试,波形良好,峰锐且呈对称。As 0.01～2.5μg/ml浓度与波高呈线性,检出限为0.blμg/ml,它比二元杂多酸极谱性能优越。方法应用于岩石及辉锑矿中微量砷的测定,结果令人满意。     

线性扫描极谱法测定青霉素

青霉素（Penicillin）又名盘尼西林,青霉素G的化学式为C16H18N2O4S,是一种高效、低毒、临床应用广泛的重要抗生素。它对革兰阳性细菌及某些革兰阴性细菌有较强的抗生作用,金黄色葡萄球菌、肺炎球菌、淋球菌及链球菌等对其高度敏感;脑膜炎双球菌、白喉杆菌、破伤风杆菌及梅毒螺旋体也很敏感。临床用于敏感菌引起的各种包急性感染,如肺炎、支气管炎、脑膜炎、心内膜炎、腹膜炎、败血症等。