Bi_2O_3-石墨烯修饰玻碳电极阳极溶出伏安法测定西洋参中的铅和镉

建立西洋参中药中重金属铅和镉含量的电化学测定方法,考察市售西洋参药材的重金属铅和镉的含量。采用Bi_2O_3-石墨烯材料修饰玻碳电极,建立了阳极溶出伏安法同时快速测定铅和镉的新方法。在10~190μg/L浓度范围内,Pb~(2+)和Cd~(2+)的溶出峰电流与Pb~(2+)和Cd~(2+)的浓度呈良好线性关系,r=0.9991/r=0.9983,回收率RSD5.00%(n=6);西洋参重金属铅和镉的含量分别为15.19、16.81μg/L。Bi_2O_3-石墨烯材料修饰玻碳电极的阳极溶出伏安法检测重金属铅和镉简便、灵敏,可用于西洋参中铅和镉的检测。     

阳极溶出伏安法快速测试陶瓷溶出铅、镉浓度

采用阳极溶出伏安法（ASV）快速测试了目前国际上日用陶瓷的主要卫生指标——溶出铅、镉浓度,并将实际样品测试结果与石墨炉原子吸收法（GF-AAS）进行了比较。结果表明,该方法对溶出铅、镉的检出限分别低于40μg/L和25μg/L,回收率为90％-110％,RSD小于5．0％,能够达到国际陶瓷卫生标准的测试要求。并且该方法与GF-AAS相比,具有仪器价格低、检测快速、简单易用等优点。     

用氨基酸共聚物/氰桥配位聚合物修饰电极同位镀铋溶出伏安法测定微量铅、镉离子

本文在玻碳电极基底上,采用多重电化学聚合法制备了氨基酸共聚物/含钕离子杂金属氰桥配位聚合物复合修饰电极(Aminoacid copolymer/Nd(III)-Fe(III)-WO42-Cy HMCPs/GCE)。在此工作电极上,用示差脉冲伏安法研究了Pb2+、Cd2+的阳极溶出伏安行为,利用同位镀铋法解决了待测离子间的相互干扰。基于这种环境友好的伏安测定原理,建立了无汞电化学法同时测定微量Pb2+、Cd2+的新方法,可将Pb2+、Cd2+的定量检测范围扩展至四个数量级;Pb2+、Cd2+溶出峰电流值与其浓度在0.01～1.0μmol/L、1.0～100μmol/L范围内呈现两段线性关系,检出限(S/N=3)分别为4.4、3.3 nmol/L。     

DVD-Ag电极阳极溶出伏安法测定枸杞子中铅和镉残留

建立了利用DVD-Ag电极阳极溶出伏安法同时快速测定铅和镉的方法,并考察了I^-对电极上的铅和镉溶出分析的影响。利用该方法测定了枸杞子中铅和镉的残留含量。结果表明,优化实验条件下,在5～50μg/L浓度范围内,Pb-对电极上的铅和镉溶出分析的影响。利用该方法测定了枸杞子中铅和镉的残留含量。结果表明,优化实验条件下,在5～50μg/L浓度范围内,Pb⁽²⁺⁾和Cd(2+)和Cd⁽²⁺⁾的溶出峰电流与Pb(2+)的溶出峰电流与Pb⁽²⁺⁾和Cd(2+)和Cd⁽²⁺⁾的浓度呈线性相关,相关系数分别为0.992 3和0.995 3,Pb(2+)的浓度呈线性相关,相关系数分别为0.992 3和0.995 3,Pb⁽²⁺⁾和Cd(2+)和Cd⁽²⁺⁾的检出限分别为0.2μg/L和2.6μg/L(S/N=3)。对该方法进行了方法学考察,包括精密度、稳定性和回收率,结果均符合相关要求。枸杞子中Pb(2+)的检出限分别为0.2μg/L和2.6μg/L(S/N=3)。对该方法进行了方法学考察,包括精密度、稳定性和回收率,结果均符合相关要求。枸杞子中Pb⁽²⁺⁾和Cd(2+)和Cd⁽²⁺⁾的残留含量测定结果与经典的电感耦合等离子体质谱法(ICP-MS)一致性较好,表明该方法可用于枸杞子中铅和镉的残留量的检测。     

DVD-Ag电极阳极溶出伏安法测定枸杞子中铅和镉残留

建立了利用DVD-Ag电极阳极溶出伏安法同时快速测定铅和镉的方法,并考察了I~-对电极上的铅和镉溶出分析的影响。利用该方法测定了枸杞子中铅和镉的残留含量。结果表明,优化实验条件下,在5～50μg/L浓度范围内,Pb~(2+)和Cd~(2+)的溶出峰电流与Pb~(2+)和Cd~(2+)的浓度呈线性相关,相关系数分别为0.992 3和0.995 3,Pb~(2+)和Cd~(2+)的检出限分别为0.2μg/L和2.6μg/L(S/N=3)。对该方法进行了方法学考察,包括精密度、稳定性和回收率,结果均符合相关要求。枸杞子中Pb~(2+)和Cd~(2+)的残留含量测定结果与经典的电感耦合等离子体质谱法(ICP-MS)一致性较好,表明该方法可用于枸杞子中铅和镉的残留量的检测。     

吸附溶出伏安法同时测定电站锅炉用水中的痕量铜、铁

建立了吸附溶出伏安法同时测定痕量铜、铁的方法.以邻苯二酚为配合剂,哌嗪-1,4-双(2-乙烷磺酸)(PIPES)为缓冲溶液,在最优条件下,对铜离子的测量范围为0～35μg/L相关系数r=0.999 4;对铁离子的测量范围为0～30μg,L,相关系数r=0.998 0.两者的检测限分别为0.069、0.407μg/L.此法应用于电站锅炉用水中痕量铜、铁的测定,回收率分别为103.6%和104.7%.说明该法不仅灵敏度高、准确性好.而且操作简单、快速.     

高灵敏度串联薄层溶出电解池研制及在尿铅测定中的应用

将薄层大面积玻碳电解池与小面积玻碳电解池以串联方式连接,在程控状态下使用.铅离子首先在大面积玻碳汞膜电极(LGCE)上预富集,溶出后在小面积玻碳汞膜电极(SGCE)上两次富集,因此提升了SGCE富集效率.测量25 0μg/L铅标准溶液,峰高的相对标准偏差RSD=1.2％.测量铅含量为25.6 μg/L的尿样,测得值27.4μg/L,相对标准偏差RSD=2 3％.富集时间400 s检出限为0.008 8 μg/L;定量检测限为0.029 2 μg/L.与常规的溶出分析比较,检出限降低11 90倍,显著提高检测的灵敏度.流动式电解池在溶出时的底液中不含样品基体.     

阳极溶出伏安法同时测定水中微量砷、汞的研究

采用微分脉冲阳极溶出伏安法同时测定了水中微量As和Hg。三电极系统以金盘电极为工作电极,以添加了盐酸羟胺的硫酸溶液为电解液。通过响应峰高的比较,找到了目标元素富集和溶出的最佳试验条件。在10-60μg/L的范围内As和Hg都线性良好,相关系数能达到0.997以上,相对标准偏差均小于3%。     

Nafion复合铋膜修饰丝网印刷电极测定痕量镉离子

制备了Nafion修饰的丝网印刷电极,并用于同位镀铋膜法测定痕量重金属离子Cd2+。将Nafion溶液滴涂在丝网印刷电极表面制得修饰电极。在含Bi3+的0.1 mol/L醋酸缓冲溶液(pH为4.7)中,将Bi3+与Cd2+共同电沉积在修饰电极表面,再以方波阳极溶出伏安法(SWSV)检测Cd2+的浓度。优化了镀膜条件,考察了Nafion膜厚度及Bi3+浓度对溶出电流的影响。在优化的条件下,0~100μg/L质量浓度范围内Cd2+浓度与溶出峰电流呈现良好的线性关系,检出限为1μg/L,重现性良好,可用于大米中痕量重金属离子Cd2+的快速测定。     

日用陶瓷铅、镉溶出浓度快速检测方法的研究

本文采用阳极溶出伏安法（ASV）快速测试了目前国际上日用陶瓷的主要卫生指标——铅、镉溶出浓度．并将实际样品的测试结果与石墨炉原子吸收法（GF—AAS）进行了比较。结果表明,该方法对溶出铅、镉的检出限分别低于40μg／U和25μg／L,回收率在90～110％之间,RSD小于5．0％,能够达到国际日用陶瓷卫生标准的测试要求。并且该方法与GF—AAS相比,具有仪器价格低、检测快速、简单易用等优点。     

汞膜电极阳极溶出伏安法测定痕量锗的研究

提出了一种以铂基汞膜电极阳极溶出伏安法测定痕量锗的方法,发现在pH 7的酒 石酸缓冲溶液中于-1.20 V和-0.50 V左右出现两个溶出峰。锗的浓度在0.01～1 mg/L范围内 与第一个峰(-1.20 V)有良好的线性关系,检出下限为1×10-9。     

微分脉冲阳极溶出伏安法测定氢溴酸右美沙芬

应用循环伏安法和微分脉冲阳极溶出伏安法在玻碳电极上对氢溴酸右美沙芬的伏安行为进行了研究。实验结果表明,在pH6.5的B-R(Britton-Robinson)缓冲底液中,氢溴酸右美沙芬在+1.01 V(vs.Ag/AgCl)处有一明显的氧化峰,在4.0×10-6~8.0×10-5mol/L范围内与峰电流呈良好的线性关系(r=0.995 1),检出限为5.6×10-7mol/L。用该方法对氢溴酸右美沙芬片进行了测定,回收率为98.6%~102.9%,结果令人满意,还对其电极反应机理进行了初步探讨。     

Simultaneous determination of lead, copper and cadmium onto mercury film supported on wax impregnated carbon paste electrode: Assessment of quantification procedures by anodic stripping voltammetry

The deposition and stripping processes of lead and copper and cadmium ions over the wide concentrations range of 1 × 10⁻⁵ to 5 × 10⁻⁹ M, have been studied at mercury film deposited on wax impregnated carbon paste electrode, using cyclic voltammetry, linear sweep anodic stripping voltammetry and differential pulse anodic stripping voltammetry. The carbon paste electrode modified with the mercury film was characterized for its physical and electrochemical properties. The parameters of deposition and stripping processes of the analytes have been investigated using standard solution of the metal ions at various concentrations and different supporting electrolytes and different pH. The linear sweep anodic stripping has been adopted for the determination of analytes at higher concentration whereas the analytes at lower concentrations were determined using DPASV. The DPASV behavior for the ions studied dependent on concentrations of the analyte as well as on the time used in the pre-concentration step. The method developed using standard solutions have been successfully applied for the determination of Cu(II), Pb(II) and Cd(II) in Fin Fish muscles and water samples.     

Interaction of Pb and Cd during anodic stripping voltammetric analysis at boron-doped diamond electrodes

Highly boron-doped diamond (BDD) films were utilized for simultaneous electrochemical measurement of micromolar-level concentrations of Pb and Cd, and for the examination of their interactions. Differential pulse anodic stripping voltammetry (DPASV) was used for this detection. This approach can help to understand the possible detection of trace metals at BDD electrodes without the aid of mercury. These metals were found to strip at their characteristic potentials, in solutions containing Cd or Pb alone, and in those containing these metals together. The mixed solutions (concentration range: 1-5 μM) yielded well-separated stripping peaks for Pb and Cd and the differential stripping peak currents for the respective metals increased linearly with increasing metal concentration. There were mutual interferences due to Pb-Cd interactions, but these can be taken into account with the aid of three-dimensional calibration plots. A model has been developed to help explain the Pb-Cd interactions.     

Graphite-epoxy composite as an alternative material to design mercury free working electrodes for stripping voltammetry

The use of graphite-epoxy composite electrodes (GECE) as an alternative to mercury or modified electrodes for stripping voltammetry is presented. The effect of preconcentration time on the peak current was studied. It is shown, unlike traditional mercury electrodes, that the accumulation of lead using GECE does not yield a saturation current even at high preconcentration times of 30 min. A preconcentration time of 1 min was chosen as a compromise between analysis time and sensitivity. The peak current was increased by decreasing pH, the pH range 1-2 being the most sensitive. Concentrations as low as 1 ppb for lead and copper and 10 ppb for cadmium in standard solutions have been detected. Both analytical results and SEM characterisation confirm the behaviour of GECE as a complex microelectrode array at a rough surface.     

铋膜电极阳极溶出伏安法测食盐中锌含量

用铋膜电极代替汞膜电极可避免环境污染。采用玻碳电极同位镀铋在酸性的KSCN介质中测定食盐中锌,结果峰形好、灵敏度高、峰电流值大,检测限为7．8×10^-8mol／L,线性范围为2．0×10^-6mol／L～1．3×10^-5mol／L,加标回收率为92．2％-102．2％。     

纳米二氧化钛膜电极测定痕量锌

以nano-TiO2膜修饰玻碳电极作为工作电极,采用线性扫描溶出伏安法测定饮料样中的痕量Zn2+。在pH值4.5的磷酸盐缓冲溶液中,Zn2+在-1.2 V电位下富集7min,再静置60s后阳极化扫描,于-0.72 V处出现一个灵敏而尖锐的阳极溶出峰。Zn2+溶出峰电流与其浓度在1.0×10-8~5.0×10-6mol.L-1范围内呈良好的线性关系,富集12 min,检出限(S/N=3)为2.5×10-9mol.L-1。方法用于实际饮料样中Zn2+的检测,结果令人满意。     

Synthesis and characterization of composite Hg-polyaniline powder material

A simple synthesis method is proposed to obtain a composite powder material constituted by polyaniline powder containing mercury droplets closely linked into PANI matrix. ¹⁹⁹Hg solid state NMR spectroscopy indicates that incorporated mercury is in a metallic form and proves a redox reaction between polyaniline (leucoemeraldine form) and an aqueous solution of Hg(I). This composite powder material has been studied by voltammetry with a cavity microelectrode (CME). This electrode appears suitable for characterizing such a material. CME containing Hg-polyaniline (Hg-PANI) powder has been used as an electrochemical microsensor for lead trace analysis by anodic stripping voltammetry of water without electrolyte addition.     

Effect of Bi(III) concentration on the stripping voltammetric response of in situ bismuth-coated carbon paste and gold electrodes

The effect of Bi(III) concentration (over the wide concentration range of 10⁻⁷ to 10⁻⁴ M) on the determination of Pb and Cd metal ions (in the 10⁻⁸ to 10⁻⁵ M range), by means of anodic stripping voltammetry (ASV) at in situ bismuth-coated carbon paste (CPE) and gold electrodes, has been studied. It is shown that in square wave anodic stripping voltammetry (SWASV) experiments the sensitivity of the technique generally depends on the Bi(III)-to-metal ion concentration ratio. It was found that, unlike the usually recommended at least 10-fold Hg(II) excess in anodic stripping experiments at in situ prepared mercury film electrodes, Bi(III)-to-metal ion ratios less than 10 are either optimal or equally effective at CPE and Au electrode substrates. Detection limits down to 0.1 μg L⁻¹ for Pb(II) and 0.15 μg L⁻¹ for Cd(II) were estimated at CPEs under conditions of small or moderate Bi(III) excess. Depending on Bi(III) concentration and deposition time, multiple stripping peaks attributed to Bi were recorded (especially in the case of Au substrates), indicating various forms of Bi deposits.     

丁香酚在活化玻碳电极上的电化学行为

用循环伏安法和差分脉冲溶出伏安法研究了丁香酚在活化玻碳电极于醋酸-醋酸钠（pH=6．0）缓冲溶液中的电化学行为。结果表明,丁香酚在该电极上于0．188V、0．485V有一对氧化还原峰,表明该电极对丁香酚有催化作用。在pH=6．0的醋酸-醋酸钠缓冲液中,用差分脉冲溶出伏安法在该电极上测定了丁香酚,线性范围为4．00×10^-6-2．58×10^-4mol／L。检测限为1．96×10^-6mol／L。成功用于样品的测定。