极谱法测定金矿石中的砷

在氢氧化钠-硼砂的底液体系中对金矿石进行极谱测定,在峰电位-0.35 V,砷的质量浓度在2～400μg/mL之间时砷的浓度与峰电流成线性关系。选用含有甘露醇的氢氧化钠硼砂的底液测定砷,精度好,准确度高,检出限为0.002μg/mL。     

甲基环糊精-对叔丁基酚包络物电化学研究及应用

本文主要研究了甲基-β-环糊精-对叔丁基酚包络物的极谱行为。在0.05mol/L的KCl底液中,甲基-?-环糊精-对叔丁基酚包络物在2.5次微分极谱仪上产生还原波,其峰电位为-0.85V(vs.SCE),其峰电位随对叔丁基酚浓度的增大而负移,峰形稳定;并且峰电流与对叔丁基酚浓度在1.0×10-5mol/L~6.0×10-5mol/L之间呈良好的线性关系,检测下限为1.0×10-5mol/L。     

2-羟基-4-甲氧基二苯甲酮的极谱行为研究

用线性扫描极谱法研究了在B-R缓冲溶液中2-羟基-4-甲氧基二苯甲酮(又名BP-3)的极谱行为。实验表明,以pH=4.90的B-R缓冲溶液和0.1 mol/L KCl溶液作为底液,BP-3产生还原波,其二阶导数峰电位为-1.21 V(vs.SCE),峰电流与其浓度在9.46×10-7~4.73×10-5mol/L范围内呈线性关系,线性方程为ip”(μA/s2)=-0.039 96 3.307×105c,相关系数r=0.999 9。初步讨论了电极过程及电极反应机理,结果表明该波为不可逆吸附波。用标准加入法测定了合成试样及市售防晒护肤霜中BP-3的质量分数。     

铟—4—（2—吡啶偶氮）间苯二酚络合吸附波的研究

在0.15mol/lNH_4Ac底液(pH6.5)中得到灵敏的铟(Ⅲ)-PAR 络合吸附波。其峰电位为-0.75V(vs.SCE)。峰电流与 In(Ⅲ)的浓度在1.0×10~■～、4.0×10~■mol/l 范围内成线性关系。用等摩尔系列法测得络合物的络合比为1:1。用循环伏安法,单扫示波极谱等研究了波的性质及其反应机理。     

2-羟基-4-甲氧基二苯甲酮-5-磺酸的极谱行为研究

用线性扫描极谱法研究了2-羟基-4-甲氧基二苯甲酮-5-磺酸(又名BP-4)的极谱行为。在2.0 mol/L H2SO4溶液中,BP-4产生还原波,波形好,其二阶导数峰电位为-0.93 V(vs.SCE),峰电流与其浓度在1.0×10-7～1.0×10-5mol/L的范围内呈良好的线性关系,线性方程为ip″(nA/s2)=187.5 1.558×108c,相关系数r=0.9996。初步讨论了电极过程及电极反应机理,该波为不可逆波。     

微机化多功能电分析仪测定农药杀菌剂三环唑

报道了农药杀菌剂三环唑有效体的脉冲极谱测定新方法。三环唑硝化产物的极谱波在磷酸缓冲溶液中 (Na3 PO4 H3 BO3 NaOH) ,其峰电位Ep =-0 .5 5V (Ag/AgCl电极 ) ,其浓度和峰高在 :1× 10 - 5mol/L～ 3.4×10 - 5mol/L时线性关系良好 ,利用该法测定了粉剂中的三环唑 ,其结果与GLC法吻合。另外 ,对极谱电极反应机理进行了较详细的论证 ,实验结果与理论推导一致性很好。     

硫酸中镉的吸附催化波研究和应用

研究了在HCI—V.C—KI—PVA混合底液体系中镉的络合吸附波的性质。对该体系进行了最佳条件选择,确定了镉的吸附催化波电位为-0.65V(vs.SCE),镉离子浓度在8.897×10~(-8)～1.335×10~(-5)mol/L范围内与波峰电流呈线性关系,测定下限4.448×10~(-8)mol/L,并对极谱机理进行了讨论。     

2,2′,4,4′-四羟基二苯甲酮的极谱行为研究

用线性扫描极谱法系统研究了2,2′,4,4′-四羟基二苯甲酮(BP-2)在不同缓冲体系中的极谱行为.实验表明,在2.5 mol/L的H2SO4溶液中BP-2的二阶导数峰电位为-1.06 V,其峰电流与浓度在5.0×10-6mol/L～3.0×10-5mol/L的对数值有良好的线性关系,线性方程ip″(nA/s2)=19 096.79+745.75×lg c(mol/L),相关系数为0.993 6.BP-2的微分循环伏安曲线表明,该极谱波为不可逆还原波.     

废水及空气中微量苯胺的极谱法分析

用极谱方法分析环境中的苯胺污染物的含量,苯胺重氮化反应产物再与亚硫酸钠、甲醛的反应物有一灵敏的二阶导数极谱波,峰电位-0.71V(vs、SCE)。研究了影响因素,优化了分析条件。线性范围在8.0×10-7～5.0×10-4mol/L,可用于废水与空气中微量苯胺的测定。     

2,2,＇4,4＇-四羟基二苯甲酮的极谱行为研究

用线性扫描极谱法系统研究了2,2,＇4,4＇-四羟基二苯甲酮（BP-2）在不同缓冲体系中的极谱行为。实验表明,在2.5 mol/L的H2SO4溶液中BP-2的二阶导数峰电位为-1.06 V,其峰电流与浓度在5.0×10^-6mol/L-3.0×10^-5mol/L的对数值有良好的线性关系,线性方程ip＂（nA/s^2）=19 096.79＋745.75×lgc（mol/L）,相关系数为0.993 6。BP-2的微分循环伏安曲线表明,该极谱波为不可逆还原波。     

孔雀石绿的电化学行为研究及应用

在HAc—NaAc缓冲溶液（pH=4．0）中,孔雀石绿在-0．745V（vs．SCE）处有一灵敏的极谱还原波,用单扫描示波极谱法建立了测定孔雀石绿的新方法,二阶导数峰电与孔雀石绿浓度在1．27×10^-7～1．78×10^-5mol／L范围内呈线性关系,相关系数为0．9988,检出限为2．54×10^-8mol／L。此法用于水样、土样中微量孔雀石绿的测定,其回收率分别在98．0％。101．2％和71．0％．83．0％。     

Cd（Ⅱ）与酰基吡唑啉酮的配位吸附波

用多种电化学方法研究了Cd（Ⅱ）与1－苯基－3－甲基－4－（a－呋喃甲酰基）－5－吡唑啉酮（HPMctFP）配位吸附波的性质及反应机理。考察了支持电解质、体系pH、配体用量、扫描的起始电位、扫描速度等对电极反应的影响。实验结果表明,在HAc—NaAc（pH=4．8）的介质中,于－0．67V（VS．SCE）处出现一尖锐、灵敏的极谱峰,此极谱波被证明为配合物的吸附波。Ca（Ⅱ）含量在0．2—12μg·mL^-1与峰电流呈线性关系,峰电流由中心离子Cd（Ⅱ）还原产生。配合物的组成为Cd^2＋：HPMαFP=1：1。     

噻吩甲酰基吡唑啉酮与Pb（Ⅱ）配合物的吸附波研究

用多种电化学方法研究了Pb（Ⅱ）与1-苯基-3-甲基-4-（α-噻吩甲酰基）-5-吡唑啉酮（HPM？TP）配位吸附波的性质及反应机理。考察了支持电解质、体系pH值、配体用量、扫描的起始电位、扫描速度等对电极反应的影响。实验结果表明,在HAc-NaAc（pH=3.1）介质中,于-0.51V（vs.SCE）处出现一尖锐、灵敏的极谱峰,此极谱波被证明为配合物的吸附波。Pb（Ⅱ）含量在0.002～8μg·mL-1与峰电流呈线性关系,峰电流由中心离子Pb（Ⅱ）还原产生。配合物的组成为Pb2＋：HPMαTP=1：2。并将其用于粗盐、麦片、化妆品样品中铅的测定,结果令人满意。     

A voltammetric investigation of the oxidation of pyrite in nitric acid solutions: relation to treatment of refractory gold ores

The anodic oxidation of pyrite on potential scans has been investigated in 0.22 mol dm^–3 nitric acid over the temperature range 26 to 80'C. The relative formation of sulphur and sulphate was determined from the anodic and cathodic charges associated with different regions of the voltammogram. It was found that the percentage of pyrite oxidizing to sulphur decreased with increase in potential to reach a negligible value at 1.5V vs SHE. No discernible change was observed in the potential dependence of the relative formation of sulphur and sulphate when the reaction temperature was varied. The significance of these results on the nitric acid treatment of refractory (sulphidic) gold ores is discussed.     

A comparison of the electrocatalytic activities of ordered mesoporous carbons treated with either HNO3 or NaOH

Ordered mesoporous carbon (OMC) was treated with HNO₃ or NaOH. The two treated OMCs have many oxygen-containing functional groups. Those treated with HNO₃ have more acidic surface groups than those treated with NaOH. Nicotinamide adenine dinucleotide (NADH) and H₂O₂ were selected as marker molecules for the comparison of the electrocatalytic property of the OMCs. A comparison between the cyclic voltammograms shows that the oxidation peak potential of NADH is 0.614 V at a bare glassy carbon electrode (GCE), 0.205 V at OMC/GCE, 0.223 V at NaOH-treated OMC/GCE, and 0.0 V at HNO₃-treated OMC/GCE (vs. Ag/AgCl). The results indicate that the HNO₃-treated OMC/GCE exhibits the highest electrocatalytic activity for NADH oxidation. Thus, acidic groups rather than other oxygen-containing functional groups, play a very important role in the catalytic activity of OMC.     

铜（Ⅱ）-孔雀石绿配合物极谱吸附波的研究

在0.5mol/L NH4C l溶液中,用单扫描示波极谱法在-0.69V（vs.SCE）可获得灵敏的铜-孔雀石绿（MG）配合物极谱吸附波,其二阶导数波峰高与孔雀石绿浓度在2.5×10-7-1.25×10-4mol/L范围内成正比关系,检出限为1.0×10-7mol/L,测得电活性配合物组成为Cu2＋：MG=1：4。该方法用于水样、土样中孔雀石绿的测定,回收率分别为95.2%-108.0%和92.0%-106.0%。     

Anodic oxidation of tellurium in NaOH solutions

The potential of tellurium anodes has been measured as a function of current density in 0.01-3 N NaOH at 30°C. The results indicate the oxidation of tellurium into tellurous acid. The initial discharge of hydroxyl ions governs the overall reaction rate within the concentration range 0.01-1 N. In concentrations above 1 N, the dual chemical-electrochemical formation of TeO is suggested to be rate-determining in the low current density range. At higher currents, hydroxyl-ion discharge again controls the reaction rate.

Accumulation of tellurous acid on the electrode surface at high anodic polarization leads to the interference of resistance overpotential, whose magnitude in dilute solutions is so large that the potential rapidly approaches 40 V. At such a potential, tellurium is probably oxidized to the trioxide.     

Determination of trace selenium by differential pulse adsorptive stripping voltammetry at a bismuth film electrode

The differential pulse adsorptive stripping voltammetric behavior of selenium (IV)-p-aminobenzene sulfonic acid-cetyltrimethylammonium bromide system at a bismuth-coated glassy carbon electrode (BiFE) has been investigated. A well-defined and sensitive stripping peak of the selenium (IV)-p-aminobenzene sulfonic acid complex was observed at −0.76 V (vs. SCE) in a 0.15 mol/L acetate solution (pH 2.9) at a deposition potential of −0.40 V (for 120 s). The linear range was 2-30 μg/L and the detection limit for an accumulation time of 300 s was 0.1 μg/L. This method was applied to determine the trace amount of selenium in the samples.     

差分脉冲阳极溶出伏安法测定中药材样品中的铜铅镉

用差分脉冲阳极溶出伏安法同时测定了8种中药材样品中铜、铅、镉的含量,它们的溶出电位依次是-0.15 V、-0.45 V、-0.65 V;铜、铅浓度在4.0×10-10~1.0×10-7g/mL范围内与峰电流呈线性关系,线性回归方程分别为y=378.84x(R2=0.9985)、y=661.96x(R2=0.9937)(x为浓度,单位10-6g/mL),镉浓度在4.0×10-10~8.0×10-7g/mL范围内与峰电流呈线性关系,回归方程为y=588.72x(R2=0.9963)(x为浓度,单位10-6g/mL),其检出限依次为1.0×10-11g/mL、1.8×10-11g/mL、1.0×10-11g/mL。此方法用于中草药样品中铜、铅、镉的测定,其回收率依次为88.06%、105.74%,、104.54%,方法简便,灵敏度高,结果准确可靠。