Electrochemical speciation of dissolved Cu, Pb and Zn in an estuarine ecosystem (Ria de Vigo, NW Spain): comparison between data treatment methods

The total concentration and chemical speciation of Cu, Pb and Zn were determined by square wave anodic stripping voltammetry (SWASV) in the Ría de Vigo, an estuarine area located in NW Spain. Surface and bottom waters from 6 locations were collected in two seasons during 3 years. The total Pb was below 1 nM, and Cu and Zn concentrations, ranged from 3 to 44 nM and from 9 to 300 nM respectively. A gradient from sampling points located in the port of Vigo to external areas was observed. The speciation of the metals (ligand concentration and apparent complex formation constant K′) was calculated using several methods: The Langmuir and Scatchard linear fits for one and two ligands, the Lorenzo non-linear fit for one ligand and Langmuir non-linear fit for two ligands. The capability of the different methods to achieve reliable results have been discussed and Langmuir linear fit as well as Lorenzo non-linear fit are the most suitable. Cu presented the highest ligand concentrations, followed by Zn and Pb, while mean log K′ values fell in the range 5-9 (±0.6) for all metals and samples. The adjustment of the data treatment methods used to calculate the speciation parameters was found to vary depending on the extent of complexation and on whether one or two ligands needed to be considered.     

线性扫描阳极溶出伏安法测定食盐中的锌

在NH3-NH4Cl缓冲溶液中,以线性扫描阳极溶出伏安法测定食盐中的锌,锌的加标回收率为99.1%-106.0%,测定结果的相对标准偏差为0.90%-4.10%。锌的浓度在0.10-0.70mg/L与峰电流强度呈线性关系,线性方程为i=2.580c 0.0500,相关系数为0.9955。     

浙江省滨海盐土及青紫泥上油菜锌肥效应及施用方法研究

土壤分析表明，浙江省土壤缺锌面积约占耕地面积的５０％左右，尤其是滨海盐土，土壤中的有效锌含量平均为０．８７×１０－６．本研究证明油菜施锌肥有一定的增产效果，其肥效与土壤有效锌含量和施锌方法有关，化学锌肥与有机肥料混合施用，可显著提高油菜施用锌肥的增产效果。     

Decomposition of vegetables for determination of Zn,Cd, Pb and Cu by stripping voltammetry

A simple and accurate digestion method using nitric acid, perchloric acid and hydrogen peroxide has been developed for use in trace analysis for heavy metals in vegetables by differential pulse anodic stripping voltammetry. The recovery of the metals from the samples is lower if the hydrogen peroxide is omitted from the digestion mixture. Standard reference materials have been analysed satisfactorily by this method.     

ICP-AES测定茶叶中多种微量元素及溶出特性

探讨南方人们最常饮用某品牌的铁观音中Mn、Zn、Cu在不同浸泡条件下的溶出特性.采用微波消解法,开水浸泡法处理样品,ICP-AES法同时测定其含量.检测结果表明随着浸泡时间温度不同其结果有着规律性的变化,且浸泡结果与微波消解结果有着显著性差异.得出的结论是茶叶中微量元素和浸泡时间,温度不同其溶出特性不同,浸泡结果远低于微波消解测定结果.     

卡尔曼滤波析相光度法同时测定锰铁铜锌镉的研究——5-Br-PADAP—Triton X-100体系

运用卡尔曼滤波递推法,以2-(5-溴-2-吡啶偶氮)—5-二乙氨基苯酚(5-Br-PADAP)为显色剂,建立了同时测定锰、铁、铜、锌、镉析相光度法.在pH9.0硼酸-氢氧化钠介质中,胶束溶液在95℃加热1h,配合物被Triton X-100相完全富集,最大吸收峰分别为锰566nm、铁556nm、铜560nm、锌562nm、镉557nm,工作曲线范围除镉为0～8μg/5ml外,其余均为0～10μg/5ml.应用于大米中锰铁铜锌镉的同时测定,结果满意.     

负载型Cu-MnOX催化剂上CO加氢制二甲醚的研究--制备方法和反应条件的影响

由直接合成二甲醚的负载型Ｃｕ－Ｍｎ－ＺｎＯｘ／γ－Ａｌ２Ｏ３催化剂不同制备方法的研究中发现：不同的浸渍步骤和催化剂的焙烧温度对反应活性和催化剂的表面活性物种的影响很大,而干燥方式的影响较小;催化剂表面少量的Ｍｎ２Ｏ３晶相存在对提高二甲醚的选择性有利,而晶相ＣｕＯ和ＭｎＯ２的存在则会降低催化剂的活性。不同反应条件的实验结果显示：温度的提高增加了催化剂的脱水性能,但是却导致催化剂的活性降低,空速大于３０００ｈ＾－１时,条件的实验结果显示,温度的提高增加了催化剂的脱水性能,但是却导致催化剂的活性降低;空速大于３０００ｈ＾－１时,ＣＯ的转化率迅速下降;原料气组成中ＣＯ含量的增加,其转化率也呈下降趋势;合成压力的提高,使ＣＯ转化率提高相当明显;二甲醚的选择在整个条件试验过程中的变化不十分明显。     

Complexing capacity profiles of naturally occurring ligands in Tempranillo wines for Cu and Zn: an electroanalytical approach for cupric casse

Complexing capacity of naturally occurring ligands in Vitis vinifera (Tempranillo variety) wines has been studied with respect to two target metals (Cu and Zn) by differential pulse anodic stripping voltammetry (DPASV). Eight commercial wines of two certified brands of origin (CBO) and a young wine along its vinification process were monitored. Conditional stability constants and total complexing ligand(s) concentration(s) have been calculated for both metals. Discussion of the particular electrochemical responses for Cu and Zn for all samples is presented. A follow-up of the Cu stripping response allowed differentiating a commercial wine from one under processing related to the cupric casse phenomenon. Interaction of Cu with two molecular forms of cyanidin has been theoretically modeled at natural wine pH.     

Cathodic and Adsorptive Stripping Votammetry of Naftazone

Abstract

Naftazone (1,2-naphthoquinone-2-semicarbazone) undergoes a reversible two-electron transfer in both acidic and alkaline solutions and also gives rise at pH > 7 to an anodic wave attributed to the formation of a mercury derivative. Cathodic stripping voltammetry is proposed to determine the compound down to 5 × 10^?9 M after accumulation of its mercury salt formed at -0.05V in a 0.05M sodium hydroxide solution. These results have been compared with those obtained by performing an adsorptive collection of the drug in a pH 3 sodium perchlorate solution. Concentrations ranging from 1 × 10^?7 to 2 × 10^?7M can be easily investigated, the detection limit being 7 × 10^?11M. The influence of several operational parameters has also been considered.     

太阳神奶对学龄前儿童全血中微量元素的影响

选择5～6岁儿童64名，随机分为两组，分别服用太阳神奶(A组)和一般乳酸奶(B组)，每天服用100mL。连服9周，检测全血中微量元素锌、铁、铜、钙、锰的变化。经检测，服用太阳神奶A组经统计学分析，微量元素锌、铁、锰呈显著或非常显著变化。     

半枝莲中铜,锰,锌的初级形态分析

按照微量元素初级形态分析要求,对抗癌中药半枝莲的原药、头煎、二煎、及其残渣、用0.45μm膜分离煎液所得的颗粒物及可溶态共7种样品中的铜、锰、锌进行测定。通过计算得到一系列形态分析参数。其中原药中微量元素含量Cu 18.56×10~(-6),Zn 149.4×10~(-6),Mn 218.8×10~(-6)。头煎提取率:Cu32.67％、Zn 43.69％、Mn 44.49％。二煎提取率:Cu 1.61％、Zn 16.13％、Mn 5.01％。     

X射线荧光光谱薄膜法测定多金属矿样中常量Pb,Zn,Cu,Fe,Mn

本文拟定了一个Ｘ射线荧光光谱薄膜测定常见铅、锌、铜、锰矿中０．２～ｘｘ％Ｐｂ、Ｚｎ、Ｃｕ、Ｆｅ、Ｍｎ的方法。实验考察了制片重现性和样品分解可靠性对本法结果的关键性影响，采用酸溶、钒作内标、Ｍｙｌａｒ膜制片测量。手续简便、方法精密度和准确性符合有色地质分析质量要求。     

Adsorptive stripping voltammetric determination of dimenhydrinate at a hanging mercury drop electrode

Dimenhydrinate exhibits a single adsorptive stripping peak at a hanging mercury drop electrode after accumulation at 0.0V vs Ag/AgCl electrode at pH 3.8 (acetate buffer). The addition of trace amounts of copper ions enhanced the dimenhydrinate peak and its height depends on the concentration of each dimenhydrinate and Cu²⁺. The adsorptive stripping response was evaluated with respect to accumulation time and potential, concentration dependence, electrolyte, the presence of other purines, surfactants and other metal ions, and some variables. The calibration graph for dimenhydrinate determination is linear over the range 2.0×10^–8–2.0×10^–7 M (pre-concentration for 60s). The correlation factor is found to be 0.985 and RSD is 3.2% at 1.0×10^–7 M. Detection limit is 1.0×10^–8 M after 5 min accumulation. The determination of dimenhydrinate in pharmaceutical formulations by the proposed method is also reported.     

硫代硫酸根的溶出伏安吸附性质及应用

在 0 .0 1mol·L-1LiNO3介质中 (pH 2 .70 )S2 O32 -有一灵敏的阴极溶出峰( - 0 .42V) ,其峰电流与S2 O32 -浓度在 1× 1 0 -7mol·L-1～ 4× 1 0 -6mol·L-1范围内有线性关系。当富集 2 0 0s时 ,检测限可达 5× 1 0 -8mol·L-1。溶出峰具有吸附性质 ,在悬汞电极上的吸附符合Frumkin等温式。测得在悬汞电极上的饱和吸附量为 1 .0 3× 1 0 -9mol·cm-2 。该方法用于PbS2 O3溶度积的测定 ,结果与文献值基本一致。     

Studies on substituted phenols by differential pulse cathodic stripping voltammetry: 1. Pentachlorophenol

A study of chlorophenols using differential pulse cathodic stripping voltammetry (dpcsv) is reported. Of the wide range of chlorophenols investigated, only pentachlorophenol and 2,3,4,6-tetrachlorophenol yield stripping peaks.For pentachlorophenol in water, two peaks are obtained at stripping potentials of –1.2 V and –1.58 V versus SCE. In methanol, pentachlorophenol shows one peak with a stripping potential at –1.6 V versus SCE.In the case of 2,3,4,6-tetrachlorophenol in water, two peaks are observed at –1.06 V and –1.6 V versus SCE, while in methanol only one peak arises at a stripping potential of –1.6 V. A procedure was developed for the determination of pentachlorophenol in natural waters.     

健康老年人与若干常量及微量元素的相关性研究

用原子吸收光谱法测定了７０例健康老年人、３０例健康成年人和３０例老年高血压病人血清中Ｃｕ、Ｚｎ、Ｆｅ、Ｍｎ、Ｃａ、Ｍｇ６种元素的含量．结果表明，健康老年人组与健康成年人组（对照组）相比，除Ｆｅ以外，Ｃｕ、Ｚｎ、Ｍｎ、Ｃａ、Ｍｇ均有显著性差异；与老年高血压病人组相比，除Ｍｇ以外，Ｃｕ、Ｚｎ、Ｆｅ、Ｍｎ、Ｃａ均有显著性差异．我们认为稳定的Ｃｕ／Ｚｎ比值及较高的血Ｍｇ水平是健康老年人未发生心血管疾病及糖尿病的重要原因之一，而高Ｃｕ、高Ｃａ及显著偏高的Ｃｕ／Ｚｎ比值，则是发生高血压的一个重要原因。     

Pb,Cu和Zn在自然水体生物膜中铁/ 锰氧化物等组分上的富集规律

用选择性萃取法萃取天然基质采集的生物膜中的铁/锰氧化物, 考察生物膜上铁/锰氧化物对水体中Pb, Cu及Zn的富集作用. 结果表明, 锰氧化物对生物膜富集Pb起主要作用, 而铁氧化物和除铁/锰氧化物以外的以有机质为主的其它组分的作用很小; 膜上其它组分对Cu的富集贡献较大, 锰氧化物的贡献与铁氧化物的接近; 锰氧化物对Zn的富集贡献最大, 铁氧化物和其它组分的贡献比较接近. 锰氧化物对Pb, Cu及Zn的富集能力分别高于铁氧化物的富集能力, 铁氧化物和锰氧化物对3种金属富集能力的大小顺序分别是Zn>Cu>Pb和Zn>Pb≥Cu.     

Cu/Zn比对微波辐射老化制备CuO/ZnO/Al2O3催化剂结构和活性的影响

在微波辐射条件下, 对共沉淀法制备合成甲醇CuO/ZnO/Al₂O₃催化剂前驱体的母液进行老化, 通过改变Cu/Zn比, 研究了微波辐射对催化剂性能的影响, 并结合XRD, FTIR, DTG, H₂-TPR, XPS等表征手段, 探讨了微波辐射对前驱体物相组成及催化剂微观结构的影响. 结果表明: 在微波辐射老化条件下, Cu/Zn比对催化剂前驱体物相组成影响较大, 微波辐射有利于绿铜锌矿(Cu, Zn)₅(CO₃)₂(OH)₆晶相选择生成. 当Cu/Zn比为2.0时, 前驱体中含有较多的绿铜锌矿物相, 且结晶较好, 焙烧后形成的催化剂中CuO-ZnO协同作用较强, CuO分散性好, 导致H₂还原温度低, 在浆态床合成甲醇过程中表现出良好的催化活性和稳定性, 甲醇时空收率(STY)达到309.0 g•kg^－1•h^－1, 失活率仅为0.11%/d, 远优于常规水浴加热制备的催化剂.