半胱氨酸/纳米金修饰电极差分脉冲伏安法测定芦丁

以半胱氨酸和纳米金自组装修饰裸金电极为基础,制备一种具有多层结构的修饰电极。研究芦丁分子在修饰电极上的电化学行为,发现通过多层结构修饰能够提高芦丁分子在金电极上的差分脉冲伏安响应灵敏度,从而建立一种使用差分脉冲伏安法测定复杂体系中芦丁含量的电化学分析检测方法。方法线性回归方程为I(μA)=0.112C(μg/m L)+0.07,相关系数R~2=0.999 3,分析方法检出限为6.0 mg/100 g,苦荞茶样品中芦丁加标浓度为2.0、5.0、7.0μg/m L时回收率在99.65%~101.10%之间。     

Nafion-碳纳米管修饰电极溶出伏安法测定大米中痕量铅

用Nafion和碳纳米管联合修饰玻碳电极,探讨铅离子在修饰电极上的溶出伏安行为。建立了基于化学修饰电极检测大米中铅的溶出伏安电化学传感方法。实验结果表明,在pH值4.0、0.1mol/L醋酸-醋酸盐溶液的缓冲体系,富集电位-0.6V,富集时间180s,铅离子浓度在0.01～1mg/L范围内与溶出峰电流呈现良好的线性关系,检测限可达5μg/L,达到大米卫生标准。该方法操作简便,检测时间不超过5min,适合大批量大米样品检测,具有很好的准确性、灵敏度和稳定性。为进一步研究重金属现场快速检测奠定良好的实验基础。     

同位镀铋方波溶出伏安法检测蜂蜜中的痕量铅

目的 采用同位镀铋方波溶出伏安法检测蜂蜜中的痕量铅。 方法 采用铋膜电极替代传统的汞膜电极,并结合方波溶出伏安法和电极同位镀铋膜法,实现对蜂蜜中痕量铅的快速检测。结果 优化了底液, pH, 铋浓度, 沉积电位和沉积时间五项最佳实验条件参数。铅在铋膜电极上可得到灵敏的溶出峰, 其溶出电位为0.580 V。在优化的实验条件下, 该方法检测铅的线性范围为5~100 μg/L(r=0.9965), 检测限低达0.630 μg/L。实验结果与石墨炉原子吸收法结果相比无显著性差异。结论 该研究为蜂蜜等食品中铅的快速、高灵敏检测提供了新的手段。     

方波溶出伏安法同时测定食盐中的痕量铅、镉

在4%的盐酸介质中,应用方波溶出伏安法,在电位-0.508V、-0.712V附近分别产生铅和镉的灵敏溶出峰,方法线性良好,具有简便、快速、灵敏度高的优点,以连续标准加入法定量分析,可适用于食盐中痕量铅、镉的连续分析检测。     

银基汞膜电极阳极溶出伏安法测定酱油中的痕量铅

<正> 铅对人体的危害极大,酱油中含量虽微,但人们食用酱油却是长期的,因此铅的累积量不可忽视。酱油中铅含量的国家卫生指标为小于1ppm。目前国内酱油生产的质量检验还没有铅的部颁分析方法。 铅的阳极溶出伏安法国内虽有很多报道,但用于酱油中的测定仅有一篇。本文拟用国产AD-2型极谱仪以银基汞膜电极为工作电极的阳极溶出伏安法测定酱油中的痕量铅。     

同位镀汞阳极溶出伏安法测定牛奶中镉、铅、铜

建立阳极溶出伏安法同时快速测定牛奶中的镉、铅和铜元素的方法。利用同位镀汞阳极溶出伏安法对 牛奶样品中镉、铅和铜元素含量进行同时测定,并对测试条件进行优化。镉、铅和铜元素峰电位分别为－0.70、 －0.52、－0.08 V;线性范围分别为0.1～40、1～80、0.5～100 μg/L;检测限为0.06、0.3、0.1 μg/L。采用该方法测 定了牛奶样品中的镉、铅和铜含量,加标回收率分别为99.57%、101.3%、98.00%,相对标准偏差（n=5）分别为 4.0%、2.9%、2.7%,将测定结果与原子吸收光谱法检测结果对比,两者无显著性差异(P＞0.05）。结果表明该方法 快速、简单、准确,可用于牛奶中镉、铅和铜元素的同时检测。     

锑膜电极阳极溶出伏安法及在水和食品重金属检测的研究进展

重金属威胁人类健康,尤其是水和食品的痕量重金属更是人们关注的焦点。本文综述了近年来锑膜修饰电极的制备和阳极溶出伏安法在痕量重金属离子检测方面的应用研究进展。首先介绍了锑膜电极的制备方法。然后,介绍了三种阳极溶出伏安法的研究进展,包括方波、差分脉冲和线性扫描阳极溶出伏安法。最后介绍锑膜及复合锑膜修饰电极在水和食品重金属检测中的应用进展。锑膜修饰电极阳极溶出伏安法测定痕量重金属有灵敏度高、选择性好、操作简单快速等优势,适用于水和食品中的重金属检测。     

阳极溶出伏安法测定饮用水中镉、铅、铜、砷

目的建立阳极溶出伏安法快速测定饮用水中镉、铅、铜、砷含量的检测方法。方法采用微波消解处理水样,以玻碳电极为工作电极,Ag/AgCl电极为参比电极,铂电极为对电极测定其溶出电流,采用外标法定量。结果在浓度为0.1～10μg/L范围内, Cd、Pb、Cu、As线性关系良好,方法检出限为0.00004～0.001 mg/L,加标回收率在98.10%～100.35%间。实际样品测定精密度小于2%。结论该方法稳定、快速、灵敏度高、准确度好,是一种高效的检测痕量重金属离子的方法。     

表面活性剂增敏差分脉冲阳极溶出伏安法测定食品中痕量镉

实验证明:一定条件下。玻碳汞膜电极作为工作电极,有适量CTAB的存在,用D.P.A.S.V法测痕量金属镉的增敏效果可达10倍以上。此法已成功应用于测定食品中的痕量镉。     

差示脉冲溶出伏安法测定皮蛋中铅含量

目的:建立一种快速、准确测定皮蛋中铅含量的方法。方法:采用LK98电化学微机分析系统,优化试验参数,如电解质浓度、pH值、电沉积电位以及脉冲间隔等。结果:线性范围为1×10-5￣7×10-5mg/mL,检出限为1×10-7mg/mL,RSD为3.5%。结论:该方法简便、快速、灵敏度高、重现性好、准确可靠。     

A Nafion-coated bismuth film electrode for the determination of heavy metals in vegetable using differential pulse anodic stripping voltammetry: An alternative to mercury-based electrodes

Mercury electrodes have been traditionally employed for achieving high reproducibility and sensitivity of the stripping technique. However, new alternative electrode materials are highly desired because of the toxicity of mercury. Bismuth is an electrode material characterized by its low toxicity and its ability to form alloys with some metals such as cadmium, lead and zinc, allowing their preconcentration at the electrode surface. In this work, we reported the simultaneous determination of Pb(II), Cd(II) and Zn(II) at the low μg/l concentration levels by differential pulse anodic stripping voltammetry (DPASV) on a Nafion-coated bismuth film electrode (NCBFE) plated in situ, and investigated the application of NCBFE to heavy metals analysis in vegetable samples. The analytical performance of NCBFE was evaluated for simultaneous determination of Pb(II), Cd(II) and Zn(II) in non-deaerated solution, with the limits of determination of 0.30 μg/l for Zn, 0.17 μg/l for Cd and Pb at a preconcentration time of 180 s. High reproducibility for NCBFE was indicated from the relative standard deviations of 2.4% for Pb, 2.0% for Cd and 3.4% for Zn at the 15 μg/l level (n = 15). The NCBFE was successfully applied to determine Pb and Cd in vegetable samples, and the results were in agreement with those of graphite furnace atomic absorption spectrometry (GFAAS).     

差分脉冲伏安法检测茶叶中痕量铅的研究

本文旨在建立差分脉冲伏安法快速测定茶叶中的铅元素的方法,利用同位镀汞阳极溶出伏安法对茶叶样品中铅元素的含量进行测定,并对测试条件进行了优化,最终选择了我国四大茶区共29种茶叶作为样品。线性范围为40⁴00μg/L;检测限为:1.2×10^-6g/L;加标回收率为:91.1%¹04.2%;相对标准偏差（n=5）为0.86%;将测定结果与国标法检测结果进行对比,具有良好的线性关系（r=0.9979）。本研究为茶叶中铅的检测开发出了快速、简单、准确的方法,可以用于实际样品的检测。      

阳极溶出伏安法同时测定高盐调味品中铅镉

采用湿法消解结合阳极溶出伏安法对沾水辣、酱油和鱼露等高盐调味品中铅镉的测定进行了方法研究。探索了仪器条件、电解质及其用量、高盐对铅镉的影响,并对酸类型及酸度的干扰、共存离子干扰进行了实验。铅、镉工作曲线的线性范围分别为2⁵0、1²0μg·L^-1,相关系数分别为0.9999和1.0000,仪器检出限为铅0.043μg·L^-1、镉0.029μg·L^-1,方法检出限为铅2.17μg·kg^-1、镉1.43μg·kg^-1。该方法测定实际样品中铅、镉含量的精密度分别为1.11%⁴.66%、0.69%⁵.34%,加标回收率分别为93.9%¹09.9%、94.7%¹07.5%。结果表明方法简便、灵敏,具有较好的选择性和可靠性。      

差分脉冲伏安法检测茶叶籽油茶多酚含量

采用电化学差分脉冲伏安法建立测定茶多酚含量新方法。选择没食子酸为茶多酚标准品,研究没食子酸电化学行为;实验发现,没食子酸分子上羟基在特定电位下易被氧化,产生响应电流,且没食子酸浓度与响应电流值呈良好线性关系,绘制标准曲线,其线性范围为0.1~1.3μg/mL,线性相关系数为0.9908,且检测上线可根据测定需要继续扩大,检出限为0.04μg/mL(S/N=3)。该法可用于茶叶籽油茶多酚含量测定。     

Simultaneous determination of ultra trace amounts of lead and cadmium in food samples by adsorptive stripping voltammetry

A selective and sensitive method for simultaneous determination of lead and cadmium by adsorptive differential pulse cathodic stripping voltammetry is presented. The method is based on adsorptive accumulation of the complexes of Pb (II) and Cd (II) ions with 2-mercaptobenzothiazole onto hanging mercury drop electrode (HMDE), followed by the reduction of the adsorbed species by differential pulse cathodic stripping voltammetry. Optimal conditions were obtained at pH 8.0, 2-mercaptobenzothiazole concentration of 1.0 × 10⁻⁴ M, the accumulation potential of −0.4 V (vs. Ag/AgCl), the accumulation time of 160 s, and the scan rate of 100 mV/s. Under optimised conditions, linear calibration curves were established for the concentration of Pb (II) and Cd (II) in the range of 0.5–70 and 0.2–30 ng/ml, respectively, with detection limit of 0.017 ng/ml for Pb (II) and 0.01 ng/ml for Cd (II). The procedure was successfully applied to the simultaneous determination of both ions in food samples (rice, soya and sugar).     

碳纳米管修饰电极差分脉冲伏安法测定微量Pb2+

以碳纳米管(CNT)修饰玻碳电极为工作电极,于-1.0V吸附富集后差分脉冲伏安法测定水中微量铅离子,实验优化了支持电解质、pH、CNT用量。从富集电位正向扫描至0V,在-0.58V处产生铅的阳极溶出峰,溶出峰电流值与Pb2+浓度在0.005～1μg/mL范围内呈良好的线性关系,线性方程为y=16.0911x-0.2284(r=0.9962),检测下限为0.005μg/mL,回收率为95.4%～105.5%,6次重复测定RSD为1.69%。碳纳米管显著改善了铅离子检测信号,所提出的检测方法简单、灵敏、快速、选择性好,能应用于实际样品测定。     

Dithizone-modified graphene oxide nano-sheet as a sorbent for pre-concentration and determination of cadmium and lead ions in food

Graphene oxide nano-sheet was modified with dithizone as a novel sorbent for selective pre-concentration and determination of Cd(II) and Pb(II) in food. The sorbent was characterised by various analytical methods and the effective parameters for Cd(II) and Pb(II) adsorption were optimised during this work. The high adsorption capacity and selectivity of this sorbent makes the method capable of fast determinations of the Cd(II) and Pb(II) content in complicated matrices even at μg l^?1 levels using commonly available instrumentation. The precision of this method was < 1.9% from 10 duplicate determinations and its accuracy verified using standard reference materials. Finally, this method was applied to the determination of Cd(II) and Pb(II) ions in common food samples and satisfactory results were obtained.