钼（Ⅵ）—7—（1—苯偶氮）—8—羟基喹啉—5—磺酸钠络合吸附研究及应用

在ｐＨ４．８的０．０１３ｍｏｌ／Ｌ的ＨＡｃ－ＮａＡｃ介质中,钼－７－（１－苯偶氮）－８－羟基喹啉－５－磺酸钠体系在滴汞电地－０．４６Ｖ电位处得到良好的吸附还原波,其二阶导数峰电流Ｉ＾ｎ,ｐ与Ｍｏ在２．５×１０＾－８－４．５×１０＾－７ｍｏｌ／Ｌ浓芳范围内呈良好的线性关系,检测限为１．２５×１０＾－８ｍｏｌ／ＬＭｏ（Ⅵ）,方法用于钢样中策量钼的测定,结果较好。     

锡（Ⅳ）—没食子酸—钒（Ⅳ）体系极谱吸附催化波的研究

在ｐＨ２．３的氯乙酸盐缓冲液中，Ｓｎ（Ⅳ）－没食子酸（ＧＡ）－Ｖ（Ⅳ）体系产生一灵敏的吸附平行催化波，峰电位为－０．５０Ｖ（ｖｓ．ＳＣＥ），二次导数峰高与锡浓度在６．７×１０＾－１０￣１．７×１０＾－６ｍｏｌ／Ｌ范围内呈良好线性关系。本文用循环伏安法等电化学方法研究了催化波的性质及电极反应机理。方法已成功地应用于罐头食品中微量锡的测定，结果满意。     

玉米素和激动素的伏安行为

玉米素和激动素在０．１ｍｏｌ／Ｌ的醋酸－醋酸钠底液里能还原，产生很好的极谱峰，检测灵敏度可达２．５×１０＾－＾８ｍｏｌ／Ｌ，峰电位分别为－１．１８Ｖ和－１．１７Ｖ（对Ａｇ／ＡｇＣｌ）。测定了电极反应决定步骤的αｎα和电化学反应的标准速率常数ｋｓ，研究了它们对Ｃｕ＾２＾＋，Ｅｕ＾３＾＋，Ｃｄ＾２＾＋，Ｚｎ＾２＾＋的电极不产生的影响。     

锡(Ⅳ)-没食子酸-钒(Ⅳ)体系极谱吸附催化波的研究

在ｐＨ ２．３ 的氯乙酸盐缓冲液中，Ｓｎ（Ⅳ）－没食子酸（ＧＡ）－Ｖ（Ⅳ）体系产生一灵敏的吸附平行催化波，峰电位为－ ０．５０ Ｖ（ｖｓ．ＳＣＥ），二次导数峰高与锡浓度在６．７×１０－ １０～１．７×１０－ ６ ｍ ｏｌ／Ｌ 范围内呈良好线性关系，检测限达３×１０－ １０ ｍ ｏｌ／Ｌ。本文用循环伏安法等电化学方法研究了催化波的性质及电极反应机理。方法已成功地应用于罐头食品中微量锡的测定，结果满意。     

6—硝基喹啉的单扫示波极谱分析

研究了６－硝基喹啉在滴汞电极上的电极过程并建立了它的单扫示波极谱测定。在０．１０ｍｏｌ／ＬＮａＣｌ底液中，６－硝基喹啉的二阶导数阴极波峰电流ｉ＂ｐ（Ｅ＂ｐ＝－０．６６ＶｖｓＳＣＥ）浓度在１．０×１０＾－７－２．５×１０＾－５ｍｏｌ／Ｌ范围内有良好线性关系，检出限为４．２×１０＾－８ｍｏｌ／Ｌ，ＲＳＤ＝１。７％（ｎ＝６）。此外还考察了多种人体内常见微量物质及表面活性剂对ｉ＂ｐ的影响。     

烟酰胺极谱行为的研究

用单扫示波极谱法，烟酰胺在ＫＨ２ＰＯ４－Ｎａ３２Ｂ４Ｏｒ－ＮａＯＨ，底液中呈出现良好的二阶导数峰，Ｅｐ＝－１．８０±０．０１Ｖ，在５×１０＾－７－２×１０＾－５ｍｏｌ／Ｌ范围内，峰高与浓度成线性关系，检测限为２．２×１０＾－７ｍｏｌ／Ｌ。此法用于ＮＡ片剂含量的测定，其结果良好。     

铜—腺嘌呤络合物吸附波的研究

了在０．０８ｍｏｌ／ＬＮａＡｃ～０．０２ｍｏｌ／ＬＨＡｃ缓冲溶液铜与腺嘌呤（Ａｄｅ）络合物的极谱行为，结果表明，扫描电压为－０．２Ｖ～－０．７Ｖ时铜－腺嘌呤络合物在单扫示波极谱上有一络合物吸附波，其一阶导数峰电位主－０．４Ｖ（ｖｓ．ＳＣＥ），腺嘌呤浓度在１．０×１０＾－６～１．０×１０＾－５ｍｏｌ／Ｌ范围内与一阶导数波高呈良好的线性关系，检出限为１．０×１０＾－７ｍｏｌ／Ｌ，实验证明，该峰具有吸附     

苯骈三唑阴离子选择性电极的研制

本报道了一种以乙基紫－苯骈三唑阴离子缔合物为活性物的ＰＶＣ基质碳棒涂膜式ＢＴＡ阴离子选择性电极的研制及其电位响应特性。在２５℃时，电极的线性响应范围５×１０＾－５－１×１０＾－２ｍｏｌ／Ｌ，检测限１．１×１０＾－５ｍｏｌ／Ｌ，响应斜率５８ｍＶ。     

锡—邻菲咯啉络合物吸附极谱波的研究及应用

研究了锡－邻菲咯啉体系的极谱行为，在ｐＨ＝２．５０的０．１０ｍｏｌ／Ｌ氯乙酸－氯乙酸钠介质中，在单扫描极谱上，Ｓｎ－邻菲咯啉络合物于－０．４１Ｖ电位处产生一良好的吸附还原波。波高与Ｓｎ的浓度在２．０×１０＾－８－４．０×１０＾－６ｍｏｌ／Ｌ范围内呈线性关系；检出限为１．０×１０＾－８ｍｏｌ／Ｌ Ｓｎ，对合金标样中的锡进行测定，取得了满意的结果。     

α-苯偶酰二肟修饰碳糊电极的制备及对合成水样中铜的测定

报道了α苯偶酰二肟修饰碳糊电极的制备及对合成水样中铜的测定，在ｐＨ４．１ 的ＢＲ缓冲溶液中通过在－ １２０Ｖ 电位下富集Ｃｕ２＋后，在－ ０２～＋ ０２Ｖ 电位范围内作阳极溶出伏安法测定。在＋ ００４８Ｖ处有一灵敏的氧化峰，峰电流与Ｃｕ２＋ 浓度在１×１０－ ７～１×１０－ ４ｍ ｏｌ／Ｌ范围内成良好的线性关系，检出限为５×１０－ ８ｍ ｏｌ／Ｌ。     

Studies on the second reciprocal derivative constant-current stripping analysis

Theoretical and experimental investigation have been made on a method called the second reciprocal derivative constant-current stripping analysis (SRD-CCSA). The SRD-CCSA is based on the measurement of the d(2)t/dE(2) signal given by the curve of (d(2)t/dE(2)) versus the electrode potential (E). The d(2)t/dE(2)-E curve gives a maximum value (d(2)t/dE(2))(max) and a maximum value ((d(2)t/dE(2)))(min), which show as two peaks on the curve. Either of the heights of the peaks and the sum of absolute values of the two peaks are proportional to the bulk concentration of the analyte in solution, and they are much larger than (dt/dE)(p) in the first reciprocal derivative constant-current stripping analysis (FRD-CCSA). The ratio of peak-peak height in the SRD-CCSA to peak height in the FRD-CCSA is about 43n (where n represents the number of electrons transferred during the electrode process for the analyte). Potential difference (W(pp)) between the two peaks is 48.2 mV n(-1) at 25 degrees C in the SRD-CCSA, which is noticeably smaller than the half-height width W(p/2), 65.5 mv n(-1), in the FRD-CCSA. The theory was verified with a home-made multireciprocal derivative measuring instrument. The experimental results were in good agreement with the theoretical ones.     

Reciprocal derivative constant-current stripping analysis

Reciprocal derivative constant-current stripping analysis (RD-CCSA) is based on the measurement of dt/dE converted from a derivative signal, dE/dt, vs. electrode potential (E) during the stripping of analyte under galvanostatic conditions from a mercury-film electrode after preconcentration. The potential transient signal (E-t) in normal chronopotentiometric stripping analysis (CPSA) is converted in RD-CCSA into a stripping peak (dT/dE)(p) the height of which is proportional to the bulk concentration of analyte in solution. The theory of RD-CCSA has been derived, and validated by the good correlation obtained between the theory and experimental data. Compared with normal CPSA, RD-CCSA is more sensitive and has higher resolution. The detection limit for cadmium is 6 x 10(-10)M. Simultaneous determination of Cd(2+), In(3+), and Tl(+) (for which the differences between the stripping peak potentials are 58 and 50 mV, respectively) which is impossible for normal CPSA, voltammetry or differential pulse polarography, has become possible with RD-CCSA.     

测定人发中铜的桑色素修饰碳糊电极吸附溶出伏安法

制作了用桑色素作修饰剂的化学修饰碳糊电极,利用该电极为工作电极,建立了测定痕量铜的新方法。在甲酸钠－盐酸缓冲溶液（pH4.6）中,在0.20V（vsSCE）下搅拌富集,铜（Ⅱ）与碳糊修饰电极表面的桑色素形成电活性络合物而吸附富集于电极表面,经－0.45V静置还原后,阳极化线性扫描,在－0.05V获得一灵敏的二次导数溶出峰。在不同富集时间下,其二次导数峰电流与铜（Ⅱ）浓度分别在1.0×10     

Catalytic stripping analysis: sensitivity enhancement for reciprocal derivative constant-current stripping determination of palladium in the presence of tin(II) during stripping

The reciprocal derivative constant-current stripping signal of palladium at a mercury film electrode is increased, as in anodic stripping voltammetry (ASV), by a factor of ca. 80 if a certain amount of tin(II) is present in the stripping solution. This catalytic stripping phenomenon has been successfully used as a means of sensitivity enhancement in constant-current stripping determination of trace palladium. The limit of detection is 4 x 10(-10)M at S/N = 3, which is about two decades lower than that obtained without tin(II) present. Linear response was observed over the range 10(-10)-10(-7)M. This method has been applied to determine palladium in waste water and mineral samples. The experimental results support the postulated mechanism of signal enhancement, namely a chemical redeposition reaction occurring during the stripping, giving a cycle of stripping and deposition and thus increasing the stripping signal.     

Simultaneous determination of cadmium and lead in urine by means of computerized potentiometric stripping analysis

In computerized potentiometric stripping analysis for cadmium and lead in urine the samples are acidified with hydrochloric acid to a total concentration equal to 0.5 M. The sample is pre-electrolyzed at —1.25 V vs. SCE for 2 min without prior sample heating or deoxygenation, the working electrode being a mercury pre-coated glassy-carbon electrode. The lead and cadmium concentrations are evaluated by means of standard addition. Detection limits are 1 nM for both elements. Results obtained by potentiometric stripping analysis and by solvent extraction/atomic absorption are compared for samples from unexposed persons and from one patient under penicillamine treatment. The relative merits of the potentiometric stripping, anodic stripping and atomic absorption techniques are discussed.     

Potentiometric stripping analysis at a stationary electrode

The feasibility of controlling the transport mechanism of the oxidizing species at the working electrode during the stripping step of potentiometric stripping analysis is demonstrated. When linear diffusion of the oxidizing species is the rate-determining mechanism at the working electrode/solution interface and when the physical properties of the medium are considered to lower the diffusion coefficient of the oxidizing species, the relative sensitivity of the technique is enhanced by a factor of 50 for all the common ions studied by potentiometric stripping analysis. Examples and comparison with the normal procedure are given for Cu, Cd, Zn, Pb, Bi, Tl and Ga. The “stationary electrode” procedure is compatible with the normal instrumentation without great modification; it is self-optimizing with respect to time and resolution and preserves all the inherent advantages of potentiometric stripping analysis compared to other electrochemical techniques of trace analysis. The enhancement of the relative sensitivity by this modification permits measurements in the 0.01–0.1 ppb range for metal ions; the total time required is 2–4 min for a single determination and the relative standard deviations are about 3%.     

Potentiometric stripping analysis and anodic stripping voltammetry for measurement of copper(II) and lead(II) complexation by fulvic acid: A comparative study

The utility of potentiometric stripping analysis (PSA) for studying the interaction of fulvic acid with Cu^II and Pb^II at pH 1.8 and 4.8 was assessed. The impact of fulvic acid on both the deposition and stripping steps was considered. In contrast to results obtained by anodic stripping voltammetry, fulvic acid influenced both these steps in PSA, and to different degrees. Surface active substances have been claimed to have self-compensatory effects in PSA; this work shows that this is not valid for heterogenous natural complexants such as fulvic acid.     

Interlaboratory quality control for lead determination in wine by potentiometric stripping analysis

Summary Computerized potentiometric stripping analysis (PSA) was used for the determination of lead in wine samples. With this analytical method the sample preparation is limited to dilution with an appropriate supporting electrolyte (0.5 mol/l HCl and 40 mg/l Hg²⁺). Due to very high sensitivity the time needed for one determination can be reduced to 2 min. This method for lead determination in wine was compared with results from voltammetry and ETAAS from various laboratories participating in two BCR studies. With PSA it is possible to determine cadmium, lead and copper in wine after a single dilution with an appropriate supporting electrolyte. For other elements such as Bi, Tl, Hg, Sn, As, Zn determination procedures are under development.     

悬汞电极电位溶出分析法研究

电位溶出分析法近年来有迅速的发展和广泛的应用,八十年代初开始的该法理论研究的进展不仅定量解释了实验事实,而且开拓了该法应用的新领域,本文报告悬汞电极电位溶出分析法的理论研究结果。     

Vergleich von Potentiometrischer Stripping-Analyse und Anodischer Stripping-Voltammetrie in der Flie?injektionsanalyse. St?rungen bei der Bleibestimmung

Summary The interferences caused by inorganic ions, organic anions and Triton X-100 in the determination of lead by flow injection potentiometric and voltammetric stripping analysis at a mercury film electrode were investigated. The experiments were performed in the concentration range of 1–10 mg/l Pb²⁺. For both methods linear calibration plots were obtained in the presence of an excess of nitrate, chloride, perchlorate and sulphate. Iodide strongly interferes due to mercury complexation.Metal ion interference caused by formation of irreversible amalgams (as in the case of codeposition of Ni, Co, Fe and Cr) is avoided by proper choice of deposition potential. No effect of water soluble reduced species, i.e. Fe(II) and Cr(II), on the stripping signals was observed. The presence of acetate, citrate and tartrate does not limit the determination of lead by potentiometric stripping analysis (PSA) but has a marked effect on anodic stripping voltammetric (ASV) signals. No influence of Triton X-100 on the determination of lead by PSA was found. In ASV 10^–3% Triton X-100 diminished the peak current by 15%.

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Herrn Prof. Dr. Rolf Neeb aus Anlaß seines 60. Geburtstags gewidmet