WO2005124334A1 - Anodic stripping voltammetry - Google Patents

Anodic stripping voltammetry Download PDF

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Publication number
WO2005124334A1
WO2005124334A1 PCT/CN2005/000818 CN2005000818W WO2005124334A1 WO 2005124334 A1 WO2005124334 A1 WO 2005124334A1 CN 2005000818 W CN2005000818 W CN 2005000818W WO 2005124334 A1 WO2005124334 A1 WO 2005124334A1
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Prior art keywords
voltage
time
enrichment
stripping voltammetry
standing
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PCT/CN2005/000818
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French (fr)
Chinese (zh)
Inventor
Wentao Liu
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Wentao Liu
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Priority claimed from CN 200410059908 external-priority patent/CN1595136A/en
Application filed by Wentao Liu filed Critical Wentao Liu
Publication of WO2005124334A1 publication Critical patent/WO2005124334A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G01N27/42—Measuring deposition or liberation of materials from an electrolyte; Coulometry, i.e. measuring coulomb-equivalent of material in an electrolyte

Definitions

  • the invention relates to a polarographic analysis method, in particular to an anodic stripping voltammetry method.
  • Anodic stripping voltammetry is an analytical method for measuring the concentration of Zn, Cd, Pb, Cu in water by polarography. It mainly includes linear anodic stripping voltammetry, alternating current anodic stripping voltammetry, square wave anodic stripping voltammetry, Pulse anodic stripping voltammetry and differential pulse anodic stripping voltammetry.
  • the anodic stripping voltammetry method includes four steps: washing, enrichment, standing and scanning. The enrichment voltage in the enriching step and the standing voltage in the standing step may change with time or may not change with time. Varying constant voltage.
  • the enrichment voltage and the standing voltage are either time-varying or constant voltage that does not change with time, but their voltage values are generally in an IV ⁇ -1. 6V Within range. Because the enrichment voltage in the enrichment step and the resting voltage in the rest step are in the range of IV ⁇ 1.6V, if the polarograph uses a silver-based mercury film working electrode, a silver-based mercury hanging working electrode, etc. When the working electrode treated with mercury is used to measure the concentration of Zn, Cd, Pb, and Cu in seawater or surface water, after using the working electrode for a period of time, the sensitivity gradually decreases.
  • the working electrode is a silver-based mercury film working electrode
  • the sensitivity is high at the beginning, as shown in the spectrum a in FIG. 4.
  • Dissolution peaks of Zn, Cd, Pb and Cu were measured.
  • the sensitivity of the silver-based mercury film working electrode will decrease, resulting in a decrease in the sensitivity of the polarograph, as shown in the spectrum b in Fig. 4, the dissolution of Zn cannot be resolved in the obtained spectrum.
  • the peaks of the dissolution peaks of Cd, Pb and Cu were also significantly reduced. In this case, the enrichment time must be extended to detect the dissolution peak of Zn.
  • the mercury-based mercury film working electrode must be re-plated with mercury, that is, electrode processing. New The processed electrode must be scanned repeatedly for a period of time to stabilize. Do not continue testing until the electrode is stable. This will not only waste test time, but also make the test process complicated.
  • the conventional anodic stripping voltammetry method is used to determine the Cu concentration in water samples, the measurement result is significantly higher than the actual value, and the accuracy is lower.
  • the graphite furnace atomic absorption method (national standard BG17378.4-1998) is a recognized method at home and abroad for measuring Cd, Pb, and Cu concentrations in seawater samples with relative accuracy.
  • Graphite furnace atomic absorption method was used to determine the concentration of Cd, Pb and Cu in a batch of unpolluted seawater samples.
  • the concentration of Cd was generally 0.03-0.1 ⁇ g / 1
  • the concentration of Pb was generally 0.3-2 ⁇ g / 1, Cu.
  • the concentration is generally 0.5-2 g / l.
  • the existing anodic stripping voltammetry was used to determine the concentrations of Cd, Pb, and Cu in the same batch of seawater.
  • the measured concentrations of Cd and Pb were basically the same as those measured by the graphite furnace atomic absorption method, and the measured Cu
  • the concentration is 5-10 g / l, sometimes even higher. The measurement result is obviously higher than the concentration measured by graphite furnace atomic absorption method.
  • An anodic stripping voltammetry method includes four steps of cleaning, enrichment, standing, and scanning in each test cycle. It is special in that at least one of the enrichment voltage in the enrichment step and the rest voltage in the rest step is lower than -1.7V for one or more periods of time.
  • the enrichment voltage is lower than -1.7V during one or more periods, which means that the enrichment voltage is lower than or equal to -1.7V, at other times during the enrichment step.
  • the enrichment voltage is higher than -1.7V, most of the time is generally in the range of lV ⁇ -1.6V.
  • the resting voltage is lower than -1.7V for a period or periods, which means that the resting voltage for at least a period of time during the resting step is lower than or equal to -1.7V, and the rest voltage is higher than one 1. 7V, most of the time is generally in the range of IV to a 1.6V.
  • the present invention can enrich the voltage for a period or periods of less than one L 7V, the resting voltage is the same as the existing anode stripping voltammetry resting voltage, that is, the resting voltage is generally between -1 V ⁇ -1.
  • the enrichment voltage can also be the same as that of the existing anode stripping voltammetry, that is, the enrichment voltage is generally in the range of IV to 1. 6V.
  • the standing voltage is in one or more periods of time. Within a 1. 7V; can also be enriched voltage and standing voltage are lower than a 1. 7V for a period or periods. In different test cycles of the same sample, the variation curves of the enrichment voltage and the standing voltage versus time are the same.
  • the enrichment voltage or the standing voltage of the present invention has different voltage values in different time periods, wherein the voltage VI is in one or more periods, and the specific voltage VI is in another period or periods.
  • the voltage VI may be a constant voltage that does not change with time, or a voltage that changes with time.
  • the voltage value of the voltage VI most of the time is in the range of IV to 1.6V; the voltage V2 may be The constant voltage that does not change with time can also be a voltage that changes with time.
  • the value of voltage V2 is lower than or equal to -1.7V.
  • the enriched voltage can be divided into voltage VI and voltage V2, and there is no voltage V2 in the standing voltage; or the static voltage can be divided into voltage VI and voltage V2, and there is no voltage V2 in the enriched voltage; Collecting voltage and standing voltage are both divided into voltage VI and voltage V2.
  • the enrichment voltage and the standing voltage are both divided into a voltage VI and a voltage V2
  • the enrichment voltage and the voltage VI in the standing voltage may be the same or different; the enrichment voltage and the voltage V2 in the standing voltage It can be the same or different.
  • the voltage V2 of the present invention is in the range of 1.7V to 100V.
  • the voltage value of the voltage VI is mostly in the range of IV to 1.6V, which is the same as the voltage value of the enrichment voltage and the standing voltage in the existing anode stripping voltammetry.
  • the voltage VI can also be changed within a short period of time from a range of less than an IV to a range of greater than 1. 7V. If the voltage V2 is a constant voltage that does not change with time, then the voltage value of the voltage V2 is selected within a range of 1.7V-100V. If the voltage V2 is a voltage that changes over time, then the voltage value of the voltage V2 varies within a range of 1 ⁇ 7 V to 100V.
  • the voltage V2 of the present invention is preferably in the range of 1.7V to 3V.
  • the voltage value of the voltage V2 is controlled within a range of 1.7V to 3V, which is mainly to prevent the enriched voltage or the standing voltage from being too low to damage the working electrode treated with mercury.
  • the time occupied by the voltage V2 of the present invention is 0.0001% ⁇ 15% of the entire enrichment time or rest time.
  • the time occupied by the voltage V2 in the above technical solution refers to the sum of the time taken by the voltage V2 in the same enrichment step, or the sum of the time taken by the voltage V2 in the same standing step. 00001% ⁇ 15%
  • the time of the voltage V2 in the enrichment step is controlled within the range of 0.0001% to 15% of the entire enrichment time, or the time of the voltage V2 in the rest step is controlled to 0.0001% to 15% of the entire rest time Within the range, it can not only activate the working electrode treated with mercury, but also prevent the working electrode treated with mercury from being destroyed by the excessively low voltage for a long time.
  • the lower the voltage value of voltage V2 the shorter the time taken by voltage V2, and the higher the voltage value of voltage V2, the longer the time taken by voltage V2.
  • the voltage V2 of the present invention may be a constant voltage that does not change with time.
  • the voltage V2 of the present invention may be a square wave.
  • the number of square waves in the above technical solution of the present invention may be one or several. When the number of square waves is one, the voltage V2 is lower than the voltage VI for a period of time. When the number of square waves is several, it means that the voltage V2 is lower than the voltage VI in a few periods.
  • the waveform diagram a in FIG. 2 shows a waveform diagram when the voltage V2 in the enrichment step and the standing step is a square wave, and the waveform diagram b in FIG. 2 shows that the voltage V2 in the enrichment step is two. Waveform of a square wave without voltage V2 in the standing step.
  • the voltage V2 of the present invention may also be a voltage that changes with time.
  • the voltage V2 of the present invention may be a part of a sine wave.
  • the voltage V2 is a part of the sine wave, which means that the voltage value in a sine wave is lower than and equal to -1.7V.
  • waveform diagram c in FIG. 2 in the enrichment voltage waveform diagram in the enrichment step, there is a half cycle of a sine wave, and in the half cycle of the sine wave, the enrichment voltage is lower than and equal to a 1. 7V portion It is voltage V2.
  • the voltage VI in the enriched voltage is maintained at 1.3 V most of the time.
  • the part where the voltage is higher than -1.7V in the half cycle of the sine wave also belongs to voltage VI.
  • the voltage V2 of the present invention may also be a part of a triangular wave.
  • the voltage V2 is a part of the triangular wave, which means that the voltage value in a triangular wave is lower than and equal to -1.7V.
  • the waveform diagram d in FIG. 2 there is a triangle wave in the enrichment voltage waveform diagram in the enrichment step, and in the triangle wave, a portion where the enrichment voltage is lower than and equal to 1.7 V is a voltage V2.
  • the voltage VI in the enriched voltage is maintained at -1.3V most of the time.
  • the part where the voltage is higher than -1.7V in the triangle wave also belongs to the voltage VI.
  • the voltage V2 of the present invention may also be a part of a trapezoidal wave.
  • the voltage V2 is a part of the trapezoidal wave, which means that the voltage value in a trapezoidal wave is lower than and equal to -1.7V.
  • waveform diagram e in FIG. 2 there is a trapezoidal wave in the enriched voltage waveform diagram in the enrichment step.
  • the portion where the enriched voltage is lower than and equal to 1. 7V is the voltage V2.
  • the voltage VI in the enriched voltage is maintained at-L 3V most of the time.
  • the part of the trapezoidal wave whose voltage is higher than -1.7V also belongs to the voltage VI.
  • QT, FT, JT, and ST represent washing time, enrichment time, standing time, and scanning time, respectively.
  • the voltage V2 may also be a combination of various waveforms such as the above-mentioned square wave, sine wave, triangle wave, trapezoidal wave, and the like.
  • the present invention activates the working electrode treated with mercury because at least one of the enrichment voltage or the standing voltage is lower than -1. 7V for a period of time or more.
  • the working life of the working electrode treated with mercury is prolonged, and the sensitivity of the polarograph is improved.
  • the working life of the working electrode treated with mercury is extended, the number of times the working electrode is processed during the test is reduced, and the test process is simplified.
  • the sensitivity of the polarograph is improved, the enrichment time can be appropriately shortened, the entire test time is greatly reduced, the analysis speed is accelerated, and the work efficiency is improved.
  • the present invention limits the range of the voltage value of the voltage V2, and also limits the time occupied by the voltage V2 in the entire enrichment step or the standing step, it can not only activate the working electrode treated with mercury To increase the sensitivity of the polarograph, and to prevent the voltage value of the voltage V2 from being too low or the voltage V2 being too long from damaging the working electrode treated with mercury, and prolonging the service life of the working electrode treated with mercury.
  • the present invention while activating the working electrode treated with mercury, it can also improve the accuracy of Cu measurement by anodic stripping voltammetry.
  • FIG. 1 is a waveform diagram of a voltage change between a working electrode and a reference electrode of a conventional anode stripping voltammetry over time;
  • FIG. 2 is five waveform diagrams of the voltage between the working electrode and the reference electrode of the present invention as a function of time;
  • FIG. 3 is a waveform diagram of the voltage between the working electrode and the reference electrode as a function of time in an embodiment of the present invention
  • Figure 4 is a polarographic instrument using a silver-based mercury film working electrode. Under five different test conditions, the same sample was measured by anodic stripping voltammetry for the concentration of Zn, Cd, Pb, and Cu in seawater. Different spectrum.
  • the existing anodic stripping voltammetry includes four steps of cleaning, enrichment, standing and scanning in each test cycle.
  • the instrument uses a polarograph, the sensitivity of the polarograph is selected as 10, and the working electrode of the polarograph uses silver.
  • Mercury based working electrode uses silver.
  • the sensitivity of the polarograph will be significantly reduced, and the spectrum shown in spectrum b in FIG. 4 is obtained.
  • the dissolution peak of Zn is significantly reduced, wherein: the dissolution peak height of Zn is 1. 13, the dissolution peak height of Cd is 1. 10, the dissolution peak height of Pb is 23. 80, and the dissolution peak height of Cu is 5. 81.
  • the enrichment time FT must be extended or the silver-based mercury film working electrode must be processed, otherwise the measurement cannot be continued. .
  • An embodiment of the present invention is an anodic stripping voltammetry method using a polarograph, which includes four steps of cleaning, enrichment, standing, and scanning in each test cycle.
  • the working electrode of the polarography apparatus continued to use the foregoing silver-based mercury film working electrode after continuous measurement for 1 hour, and the measurement sample also continued to use the foregoing measurement sample.
  • the sensitivity of the polarography apparatus was continuously selected as 10.
  • the waveform of the voltage between the working electrode and the reference electrode as a function of time is shown in Fig. 3.
  • the enrichment voltage is not constant during the entire enrichment time, but in two periods. Is a constant voltage VI that does not change with time, and a voltage V2 that is lower than the voltage VI for another period of time.
  • the enrichment voltage is a constant voltage VI that does not change with time within the first 12 seconds of the entire enrichment time, and the voltage value is one L 3V; from the moment when the 12th second of the enrichment time ends, the enrichment voltage jumps to one
  • the voltage V2 is lower than the voltage VI, and the voltage V2 is a square wave voltage.
  • the voltage value of the square wave voltage is -2.2V, and the width of the square wave is 1 second.
  • the enrichment voltage 3V ⁇ It becomes a constant voltage VI that does not change with time, and the voltage value is -1.3V.
  • the time of the voltage V2 accounts for 2.78% of the entire enrichment time.
  • the spectrum c in FIG. 4 is not a stable spectrum and cannot be directly used for analysis and calculation.
  • the peak height of the spectrum is repeatedly stable, and the spectrum shown in spectrum d in FIG. 4 is obtained.
  • the dissolution peak height of Zn is 11.60
  • the dissolution peak height of Cd is 4.57
  • the dissolution peak height of Pb is 34.16
  • the elution peak height of Cu was 7.79.
  • the spectrum e is the spectrum obtained by measuring the same sample for two or three consecutive times, and then re-taking the non-spiked sample.
  • the dissolution peak height of Zn is 12.01
  • the dissolution peak height of Cd is 4.57
  • the dissolution peak height of Pb is 34. 18
  • the dissolution peak height of Cu is 1.15.

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Abstract

The anodic stripping voltammetry for polarographic analysis comprises four steps in a measure period, including cleaning, enrichment, standing and scanning. In one period or several periods of time during the enrichment step and the standing step, at least one of votages of the votage of enrichment and the votage of standing is below -1.7V. The voltage is V1 in one period or several periods of time during enrichment step or standing step, but it is V2 in the other period or other periods of time, wherin V2 is lower than V1. The voltage of V2 could keep constant or be different with time, such as a part of sine wave, square wave, a part of triangle wave, or a part of trpezoidal wave. The present invention can activate the working electrode of silver based mercury film.

Description

阳极溶出伏安法 技术领域：  Anode stripping voltammetry Technical field:
本发明涉及一种极谱分析方法， 具体讲是一种阳极溶出伏安法。  The invention relates to a polarographic analysis method, in particular to an anodic stripping voltammetry method.
背景技术： Background technique:
阳极溶出伏安法是一种采用极谱仪测量水中 Zn、 Cd、 Pb、 Cu浓度的分 析方法， 主要包括线性阳极溶出伏安法、 交流阳极溶出伏安法、 方波阳极溶 出伏安法、 脉冲阳极溶出伏安法和微分脉冲阳极溶出伏安法等。 阳极溶出伏 安法都包括清洗、 富集、 静置和扫描四个步骤， 在富集步骤中的富集电压和 静置步骤中的静置电压可以是随时间变化的， 也可以是不随时间变化的恒定 电压。  Anodic stripping voltammetry is an analytical method for measuring the concentration of Zn, Cd, Pb, Cu in water by polarography. It mainly includes linear anodic stripping voltammetry, alternating current anodic stripping voltammetry, square wave anodic stripping voltammetry, Pulse anodic stripping voltammetry and differential pulse anodic stripping voltammetry. The anodic stripping voltammetry method includes four steps: washing, enrichment, standing and scanning. The enrichment voltage in the enriching step and the standing voltage in the standing step may change with time or may not change with time. Varying constant voltage.
1998年 11月 11日， 发明专利公报上公告了一名称为 "极谱阳极溶出分 析法"的发明专利， 申请号： 94110779. 5, 授权公开号： CN 1040689C。 该 专利属于一种线性阳极溶出伏安法， 该专利的说明书中对阳极溶出伏安法的 基本工作原理进行了较为详细地描述。 在 94110779. 5号专利公开的阳极溶 出伏安法中， 富集步骤中的富集电压和静置步骤中的静置电压都是不随时间 变化的恒定电压， 该电压就是扫描的起始电压， 其工作电极与参比电极之间 的电压随时间变化的波形图如图 1所示， 图 1中的 QT、 FT、 JT和 ST分别 表示清洗时间、 富集时间、 静置时间和扫描时间。  On November 11, 1998, the invention patent gazette announced an invention patent entitled "Polarographic Anode Dissolution Analysis Method", application number: 94110779. 5, authorized publication number: CN 1040689C. This patent belongs to a linear anodic stripping voltammetry, and the basic working principle of the anodic stripping voltammetry is described in detail in the specification of this patent. In the anode stripping voltammetry disclosed in the 94110779.5 patent, both the enrichment voltage in the enrichment step and the rest voltage in the rest step are constant voltages that do not change with time, and this voltage is the starting voltage of the scan. The waveform of the voltage between the working electrode and the reference electrode as a function of time is shown in Fig. 1. QT, FT, JT, and ST in Fig. 1 represent the cleaning time, the enrichment time, the standing time, and the scanning time, respectively.
在上述现有的阳极溶出伏安法中， 富集电压和静置电压要么是随时间变 化的， 要么是不随时间变化的恒定电压， 但它们的电压值一般都在一 IV〜一 1. 6V范围内。 由于富集步骤中的富集电压和静置步骤中的静置电压都在一 IV〜― 1. 6V范围内， 如果极谱仪采用银基汞膜工作电极、 银基悬汞工作 电极等用汞处理的工作电极， 在测定海水或地面水中的 Zn、 Cd、 Pb、 Cu 的浓度时， 工作电极使用一段时间后， 会出现灵敏度逐渐降低的现 象。 例如， 在釆用线性阳极溶出伏安法测量时， 如果工作电极采用银基汞 膜工作电极， 开始时， 灵敏度较高， 如图 4中的谱图 a所示， 在得到的 谱图中能够测出 Zn、 Cd、 Pb和 Cu的溶出峰。 但是， 分析几个样品后， 银 基汞膜工作电极灵敏度就会下降， 导致极谱仪的灵敏度下降， 如图 4 中的 谱图 b所示， 在得到的谱图中分辨不出 Zn的溶出峰， Cd、 Pb和 Cu的溶出 峰高也明显降低。 在这种情况下， 必须延长富集时间才能测出 Zn的溶出 峰。 但是， 分析几个样品后， 灵敏度又会继续下降， 使测试无法进行。 这时， 必须对银基汞膜工作电极进行重新镀汞膜处理， 即电极处理。 新 处理的电极， 必须重复扫描一段时间才能稳定。 电极稳定后， 才能继续 进行测试。 这样不但浪费测试时间， 而且测试过程复杂。 另外， 采用上 述现有的阳极溶出伏安法测定水样中 Cu的浓度时， 测量结果比实际值明 显偏高， 准确度较低。 例如， 石墨炉原子吸收法（国标 BG17378.4-1998)是 国内外公认的测量海水样品中 Cd、 Pb和 Cu的浓度比较准确的方法。采用石 墨炉原子吸收法测定一批没有污染的海水样品中 Cd、 Pb和 Cu的浓度， Cd 的浓度一般为 0.03-0.1 μ g/1, Pb的浓度一般为 0.3-2 μ g/1, Cu的浓度一般为 0.5 — 2 g/l。 采用现有的阳极溶出伏安法测定同一批海水中的 Cd、 Pb和 Cu的 浓度，测出的 Cd和 Pb的浓度与采用石墨炉原子吸收法测出的结果基本一致， 而测出的 Cu的浓度在 5— 10 g/l，有时甚至更高，测量结果明显高于采用石 墨炉原子吸收法测出的浓度。 In the above-mentioned existing anode stripping voltammetry, the enrichment voltage and the standing voltage are either time-varying or constant voltage that does not change with time, but their voltage values are generally in an IV ~ -1. 6V Within range. Because the enrichment voltage in the enrichment step and the resting voltage in the rest step are in the range of IV ~ 1.6V, if the polarograph uses a silver-based mercury film working electrode, a silver-based mercury hanging working electrode, etc. When the working electrode treated with mercury is used to measure the concentration of Zn, Cd, Pb, and Cu in seawater or surface water, after using the working electrode for a period of time, the sensitivity gradually decreases. For example, when measuring by linear anodic stripping voltammetry, if the working electrode is a silver-based mercury film working electrode, the sensitivity is high at the beginning, as shown in the spectrum a in FIG. 4. Dissolution peaks of Zn, Cd, Pb and Cu were measured. However, after analyzing several samples, the sensitivity of the silver-based mercury film working electrode will decrease, resulting in a decrease in the sensitivity of the polarograph, as shown in the spectrum b in Fig. 4, the dissolution of Zn cannot be resolved in the obtained spectrum. The peaks of the dissolution peaks of Cd, Pb and Cu were also significantly reduced. In this case, the enrichment time must be extended to detect the dissolution peak of Zn. However, after analyzing several samples, the sensitivity will continue to decrease, making the test impossible. At this time, the mercury-based mercury film working electrode must be re-plated with mercury, that is, electrode processing. New The processed electrode must be scanned repeatedly for a period of time to stabilize. Do not continue testing until the electrode is stable. This will not only waste test time, but also make the test process complicated. In addition, when the conventional anodic stripping voltammetry method is used to determine the Cu concentration in water samples, the measurement result is significantly higher than the actual value, and the accuracy is lower. For example, the graphite furnace atomic absorption method (national standard BG17378.4-1998) is a recognized method at home and abroad for measuring Cd, Pb, and Cu concentrations in seawater samples with relative accuracy. Graphite furnace atomic absorption method was used to determine the concentration of Cd, Pb and Cu in a batch of unpolluted seawater samples. The concentration of Cd was generally 0.03-0.1 μg / 1, and the concentration of Pb was generally 0.3-2 μg / 1, Cu. The concentration is generally 0.5-2 g / l. The existing anodic stripping voltammetry was used to determine the concentrations of Cd, Pb, and Cu in the same batch of seawater. The measured concentrations of Cd and Pb were basically the same as those measured by the graphite furnace atomic absorption method, and the measured Cu The concentration is 5-10 g / l, sometimes even higher. The measurement result is obviously higher than the concentration measured by graphite furnace atomic absorption method.
发明内容： Summary of the invention:
本发明要解决的技术问题是， 现有的阳极溶出伏安法如果极谱仪采用用 汞处理的工作电极，工作电极使用一段时间后会导致极谱仪的灵敏度下 降， 并且测出的 Cu的浓度明显偏高， 准确度较低。 为解决该技术问题， 本发明采用以下技术方案： 一种阳极溶出伏安法， 在每一个测试周期中包 括清洗、 富集、 静置、 扫描四个步骤。 它的特殊之处是： 在富集步骤中的富 集电压和静置步骤中的静置电压至少有一个在一段或者几段时间内低于一 1. 7V。  The technical problem to be solved by the present invention is that if the existing anodic stripping voltammetry method uses a working electrode treated with mercury, the working electrode will be used after a period of time, which will cause the sensitivity of the polarography to decrease, and the measured Cu The concentration is significantly higher and the accuracy is lower. To solve this technical problem, the present invention adopts the following technical scheme: An anodic stripping voltammetry method includes four steps of cleaning, enrichment, standing, and scanning in each test cycle. It is special in that at least one of the enrichment voltage in the enrichment step and the rest voltage in the rest step is lower than -1.7V for one or more periods of time.
在上述技术方案中， 富集电压在一段或者几段时间内低于一 1. 7V, 是 指在富集步骤中至少有一段时间的富集电压低于或者等于一 1. 7V,其它时间 的富集电压高于一 1. 7V, 大部分时间一般在一 lV^ ^— 1. 6V 范围内。 静置电 压在一段或者几段时间内低于一 1. 7V，是指在静置步骤中至少有一段时间的 静置电压低于或者等于一 1. 7V,其它时间的静置电压高于一 1. 7V,大部分时 间一般在一 IV〜一 1. 6V范围内。 本发明可以富集电压在一段或者几段时间 内低于一 L 7V, 静置电压与现有的阳极溶出伏安法的静置电压相同， 即 静置电压一般在— 1 V〜一 1. 6V范围内； 也可以富集电压与现有的阳极溶 出伏安法的富集电压相同， 即富集电压一般在一 IV〜― 1. 6V范围.内， 静 置电压在一段或者几段时间内低于一 1. 7V; 还可以富集电压和静置电压都 在一段或者几段时间内低于一 1. 7V。 本发明在同一样品的不同测试周期中， 富集电压和静置电压对时间的变化曲线是相同的。  In the above technical solution, the enrichment voltage is lower than -1.7V during one or more periods, which means that the enrichment voltage is lower than or equal to -1.7V, at other times during the enrichment step. The enrichment voltage is higher than -1.7V, most of the time is generally in the range of lV ^^-1.6V. The resting voltage is lower than -1.7V for a period or periods, which means that the resting voltage for at least a period of time during the resting step is lower than or equal to -1.7V, and the rest voltage is higher than one 1. 7V, most of the time is generally in the range of IV to a 1.6V. The present invention can enrich the voltage for a period or periods of less than one L 7V, the resting voltage is the same as the existing anode stripping voltammetry resting voltage, that is, the resting voltage is generally between -1 V ~ -1. In the range of 6V, the enrichment voltage can also be the same as that of the existing anode stripping voltammetry, that is, the enrichment voltage is generally in the range of IV to 1. 6V. The standing voltage is in one or more periods of time. Within a 1. 7V; can also be enriched voltage and standing voltage are lower than a 1. 7V for a period or periods. In different test cycles of the same sample, the variation curves of the enrichment voltage and the standing voltage versus time are the same.
本发明的富集电压或者静置电压在不同的时间段内电压值不同， 其中在 一段或几段时间内为电压 VI， 在另外一段或者几段时间内为一个比电压 VI 低的电压 V2。 The enrichment voltage or the standing voltage of the present invention has different voltage values in different time periods, wherein the voltage VI is in one or more periods, and the specific voltage VI is in another period or periods. Low voltage V2.
在上述技术方案中， 电压 VI可以是不随时间变化的恒定电压， 也可以 是随时间变化的电压， 电压 VI的电压值大部分时间一 在一IV〜一 1. 6V范 围内； 电压 V2可以是不随时间变化的恒定电压， 也可以是随时间变化电压， 电压 V2 的值低于或者等于— 1. 7V。 本发明可以是富集电压分为电压 VI 和电压 V2， 而静置电压中没有电压 V2; 也可以是静置电压分为电压 VI和 电压 V2， 而富集电压中没有电压 V2; 还可以富集电压和静置电压都分为电 压 VI和电压 V2。 在富集电压和静置电压都分为电压 VI和电压 V2的情况 下， 富集电压与静置电压中的电压 VI可以相同， 也可以不相同； 富集电压 与静置电压中的电压 V2可以相同， 也可以不相同。  In the above technical solution, the voltage VI may be a constant voltage that does not change with time, or a voltage that changes with time. The voltage value of the voltage VI most of the time is in the range of IV to 1.6V; the voltage V2 may be The constant voltage that does not change with time can also be a voltage that changes with time. The value of voltage V2 is lower than or equal to -1.7V. In the present invention, the enriched voltage can be divided into voltage VI and voltage V2, and there is no voltage V2 in the standing voltage; or the static voltage can be divided into voltage VI and voltage V2, and there is no voltage V2 in the enriched voltage; Collecting voltage and standing voltage are both divided into voltage VI and voltage V2. In the case where the enrichment voltage and the standing voltage are both divided into a voltage VI and a voltage V2, the enrichment voltage and the voltage VI in the standing voltage may be the same or different; the enrichment voltage and the voltage V2 in the standing voltage It can be the same or different.
本发明的电压 V2在一 1. 7V〜一 100V范围内。  The voltage V2 of the present invention is in the range of 1.7V to 100V.
在上述技术方案中， 电压 VI的电压值大部分时间在一 IV〜一 1. 6V范围 内， 与现有的阳极溶出伏安法中的富集电压和静置电压的电压值相同。 为了 使电压 VI与电压 V2的波形相互衔接， 电压 VI在短时间内也可以在低于一 IV到高于一1. 7V范围内变化。 如果电压 V2是不随时间变化的恒定电压， 那么电压 V2的电压值在一 1. 7V- 100V范围内选择。 如果电压 V2是随时 间变化的电压， 那么电压 V2的电压值在一 1 · 7 V〜一 100V范围内变化。  In the above technical solution, the voltage value of the voltage VI is mostly in the range of IV to 1.6V, which is the same as the voltage value of the enrichment voltage and the standing voltage in the existing anode stripping voltammetry. In order to connect the waveforms of the voltage VI and the voltage V2 to each other, the voltage VI can also be changed within a short period of time from a range of less than an IV to a range of greater than 1. 7V. If the voltage V2 is a constant voltage that does not change with time, then the voltage value of the voltage V2 is selected within a range of 1.7V-100V. If the voltage V2 is a voltage that changes over time, then the voltage value of the voltage V2 varies within a range of 1 · 7 V to 100V.
本发明的电压 V2最好在一 1. 7V〜一 3V范围内。  The voltage V2 of the present invention is preferably in the range of 1.7V to 3V.
电压 V2的电压值控制在一 1. 7V〜一 3V范围内，主要是为了防止富集电 压或者静置电压过低而破坏用汞处理的工作电极。  The voltage value of the voltage V2 is controlled within a range of 1.7V to 3V, which is mainly to prevent the enriched voltage or the standing voltage from being too low to damage the working electrode treated with mercury.
本发明的电压 V2所占的时间为整个富集时间或者静置时间的 0. 00001 %〜15 %。  00001% 〜15%。 The time occupied by the voltage V2 of the present invention is 0.0001% ~ 15% of the entire enrichment time or rest time.
上述技术方案中电压 V2所占的时间是指在同一个富集步骤中电压 V2 所用时间的和， 或者在同一个静置步骤中电压 V2所用时间的和。 在富集步 骤中电压 V2的时间控制在整个富集时间的 0. 00001 %〜15%范围内，或者在 静置步骤中电压 V2的时间控制在整个静置时间的 0. 00001 %〜15%范围内， 既可以起到活化用汞处理的工作电极的作用， 又可以防止用汞处理的工 作电极被长时间的过低电压所破坏。一般情况下，电压 V2的电压值越低， 电压 V2所占用的时间越短， 电压 V2的电压值越高， 电压 V2所占用的时间 越长。  The time occupied by the voltage V2 in the above technical solution refers to the sum of the time taken by the voltage V2 in the same enrichment step, or the sum of the time taken by the voltage V2 in the same standing step. 00001% 〜15% The time of the voltage V2 in the enrichment step is controlled within the range of 0.0001% to 15% of the entire enrichment time, or the time of the voltage V2 in the rest step is controlled to 0.0001% to 15% of the entire rest time Within the range, it can not only activate the working electrode treated with mercury, but also prevent the working electrode treated with mercury from being destroyed by the excessively low voltage for a long time. Generally, the lower the voltage value of voltage V2, the shorter the time taken by voltage V2, and the higher the voltage value of voltage V2, the longer the time taken by voltage V2.
本发明的电压 V2可以为不随时间变化的恒定电压。  The voltage V2 of the present invention may be a constant voltage that does not change with time.
电压 V2是不随时间变化的恒定电压时， 本发明的电压 V2可以为方波。 本发明上述技术方案中的方波的个数可以是一个， 也可以是几个。 当方 波的个数是一个时，就是在一段时间内电压 V2比电压 VI低。当方波的个数 是几个时，就是在几段时间内电压 V2比电压 VI低。图 2中波形图 a表示了 本发明在富集步骤和静置步骤中电压 V2各是一个方波时的波形图， 图 2中 波形图 b表示了本发明在富集步骤中电压 V2是两个方波， 在静置步骤中没 有电压 V2时的波形图。 When the voltage V2 is a constant voltage that does not change with time, the voltage V2 of the present invention may be a square wave. The number of square waves in the above technical solution of the present invention may be one or several. When the number of square waves is one, the voltage V2 is lower than the voltage VI for a period of time. When the number of square waves is several, it means that the voltage V2 is lower than the voltage VI in a few periods. The waveform diagram a in FIG. 2 shows a waveform diagram when the voltage V2 in the enrichment step and the standing step is a square wave, and the waveform diagram b in FIG. 2 shows that the voltage V2 in the enrichment step is two. Waveform of a square wave without voltage V2 in the standing step.
本发明的电压 V2还可以为随时间变化的电压。  The voltage V2 of the present invention may also be a voltage that changes with time.
电压 V2是随时间变化的电压时，本发明的电压 V2可以为正弦波的一部 分。  When the voltage V2 is a voltage that changes with time, the voltage V2 of the present invention may be a part of a sine wave.
在上述技术方案中， 电压 V2为正弦波的一部分是指在一个正弦波中电 压值低于和等于一 1. 7V的部分。如图 2中波形图 c所示，在富集步骤中的富 集电压波形图中有一个正弦波的半周， 在该正弦波的半周中， 富集电压低于 和等于一 1. 7V的部分是电压 V2。 在该波形图中， 富集电压中的电压 VI大 部分时间维持在一 1. 3V。 为了使电压 VI与电压 V2的波形图相互衔接， 在 正弦波的半周中富集电压高于一 1. 7V的部分也属于电压 VI。  In the above technical solution, the voltage V2 is a part of the sine wave, which means that the voltage value in a sine wave is lower than and equal to -1.7V. As shown in waveform diagram c in FIG. 2, in the enrichment voltage waveform diagram in the enrichment step, there is a half cycle of a sine wave, and in the half cycle of the sine wave, the enrichment voltage is lower than and equal to a 1. 7V portion It is voltage V2. In this waveform diagram, the voltage VI in the enriched voltage is maintained at 1.3 V most of the time. In order to connect the waveforms of voltage VI and voltage V2 to each other, the part where the voltage is higher than -1.7V in the half cycle of the sine wave also belongs to voltage VI.
电压 V2是随时间变化的电压时，本发明的电压 V2还可以为三角波的一 部分。  When the voltage V2 is a voltage that changes with time, the voltage V2 of the present invention may also be a part of a triangular wave.
在上述技术方案中， 电压 V2为三角波的一部分是指在一个三角波中电 压值低于和等于一 1. 7V的部分。如图 2中波形图 d所示，在富集步骤中的富 集电压波形图中有一个三角波， 在该三角波中， 富集电压低于和等于一 1. 7V 的部分是电压 V2。在该波形图中， 富集电压中的电压 VI大部分时间维持在 — 1. 3V。 为了使电压 VI与电压 V2的波形图相互衔接， 在三角波中富集电 压高于一 1. 7V的部分也属于电压 VI。  In the above technical solution, the voltage V2 is a part of the triangular wave, which means that the voltage value in a triangular wave is lower than and equal to -1.7V. As shown in the waveform diagram d in FIG. 2, there is a triangle wave in the enrichment voltage waveform diagram in the enrichment step, and in the triangle wave, a portion where the enrichment voltage is lower than and equal to 1.7 V is a voltage V2. In this waveform, the voltage VI in the enriched voltage is maintained at -1.3V most of the time. In order to connect the waveforms of the voltage VI and the voltage V2 to each other, the part where the voltage is higher than -1.7V in the triangle wave also belongs to the voltage VI.
电压 V2是随时间变化的电压时，本发明的电压 V2还可以为梯形波的一 部分。  When the voltage V2 is a voltage that changes with time, the voltage V2 of the present invention may also be a part of a trapezoidal wave.
在上述技术方案中， 电压 V2为梯形波的一部分是指在一个梯形波中电 压值低于和等于一 1. 7V的部分。如图 2中波形图 e所示，在富集步骤中的富 集电压波形图中有一个梯形波， 在该梯形波中， 富集电压低于和等于一 1. 7V 的部分是电压 V2。在该波形图中， 富集电压中的电压 VI大部分时间维持在 — L 3V。 为了使电压 VI与电压 V2的波形图相互衔接， 在梯形波中富集电 压高于一 1. 7V的部分也属于电压 VI。  In the above technical solution, the voltage V2 is a part of the trapezoidal wave, which means that the voltage value in a trapezoidal wave is lower than and equal to -1.7V. As shown in waveform diagram e in FIG. 2, there is a trapezoidal wave in the enriched voltage waveform diagram in the enrichment step. In the trapezoidal wave, the portion where the enriched voltage is lower than and equal to 1. 7V is the voltage V2. In this waveform, the voltage VI in the enriched voltage is maintained at-L 3V most of the time. In order to connect the waveforms of the voltage VI and the voltage V2 to each other, the part of the trapezoidal wave whose voltage is higher than -1.7V also belongs to the voltage VI.
在图 2中， QT、 FT、 JT和 ST分别表示清洗时间、 富集时间、 静置时间 和扫描时间。 电压 V2还可以是上述方波、 正弦波、 三角波、 梯形波等多种波形的组 合。 In FIG. 2, QT, FT, JT, and ST represent washing time, enrichment time, standing time, and scanning time, respectively. The voltage V2 may also be a combination of various waveforms such as the above-mentioned square wave, sine wave, triangle wave, trapezoidal wave, and the like.
与现有的阳极溶出伏安法相比， 本发明由于富集电压或者静置电压至少 有一个在一段或者几段时间内低于— 1. 7V, 对用汞处理的工作电极起到活 化作用， 延长了用汞处理的工作电极的使用寿命， 提高了极谱仪的灵敏 度。 由于用汞处理的工作电极的使用寿命延长， 在测试过程中减少了处 理工作电极的次数，使测试过程变得简单。由于提高了极谱仪的灵敏度， 可以适当縮短富集的时间， 使整个测试时间大大减少， 加快了分析的速 度， 提高了工作效率。 由于本发明对电压 V2的电压值的范围进行了限定， 对电压 V2在整个富集步骤或者静置步骤中所占的时间也进 了限定， 不但 可以对用汞处理的工作电极起到活化作用， 提高极谱仪的灵敏度， 而且 可以防止电压 V2的电压值过低或者电压 V2的时间过长对用汞处理的工作 电极造成破坏， 延长了用汞处理的工作电极的使用寿命。 另外， 采用本 发明后， 对用汞处理的工作电极起到活化作用的同时， 还能提高阳极溶 出伏安法测量 Cu的准确度。  Compared with the existing anode stripping voltammetry, the present invention activates the working electrode treated with mercury because at least one of the enrichment voltage or the standing voltage is lower than -1. 7V for a period of time or more. The working life of the working electrode treated with mercury is prolonged, and the sensitivity of the polarograph is improved. As the working life of the working electrode treated with mercury is extended, the number of times the working electrode is processed during the test is reduced, and the test process is simplified. As the sensitivity of the polarograph is improved, the enrichment time can be appropriately shortened, the entire test time is greatly reduced, the analysis speed is accelerated, and the work efficiency is improved. Since the present invention limits the range of the voltage value of the voltage V2, and also limits the time occupied by the voltage V2 in the entire enrichment step or the standing step, it can not only activate the working electrode treated with mercury To increase the sensitivity of the polarograph, and to prevent the voltage value of the voltage V2 from being too low or the voltage V2 being too long from damaging the working electrode treated with mercury, and prolonging the service life of the working electrode treated with mercury. In addition, after adopting the present invention, while activating the working electrode treated with mercury, it can also improve the accuracy of Cu measurement by anodic stripping voltammetry.
附图说明： Brief description of the drawings:
图 1为现有的阳极溶出伏安法的工作电极与参比电极之间的电压随时间 变化的波形图；  FIG. 1 is a waveform diagram of a voltage change between a working electrode and a reference electrode of a conventional anode stripping voltammetry over time;
图 2为本发明的工作电极与参比电极之间的电压随时间变化的五种波形 图；  FIG. 2 is five waveform diagrams of the voltage between the working electrode and the reference electrode of the present invention as a function of time;
图 3为本发明的实施例中工作电极与参比电极之间的电压随时间变化的 波形图；  3 is a waveform diagram of the voltage between the working electrode and the reference electrode as a function of time in an embodiment of the present invention;
图 4为极谱仪采用银基汞膜工作电极， 在五种不同的测试条件下， 对同一样品用阳极溶出伏安法测量海水中的 Zn、 Cd、 Pb、 Cu浓度， 所得 到的五种不同的谱图。  Figure 4 is a polarographic instrument using a silver-based mercury film working electrode. Under five different test conditions, the same sample was measured by anodic stripping voltammetry for the concentration of Zn, Cd, Pb, and Cu in seawater. Different spectrum.
具体实施方式： detailed description:
下面结合附图对本发明的实施例进行详细描述。  The embodiments of the present invention will be described in detail below with reference to the drawings.
为了将本发明的实施例与现有的阳极溶出伏安法的技术效果进行比较， 在介绍本发明的实施例以前， 首先采用现有的阳极溶出伏安法测量某一海水 样品中的 Zn、 Cd、 Pb、 Cu的浓度。 现有阳极溶出伏安法在每一个测试周期 中包括清洗、 富集、 静置和扫描四个步骤， 仪器采用极谱仪， 极谱仪的灵敏 度选为 10 ，极谱仪的工作电极采用银基汞膜工作电极。该阳极溶出伏安法 工作电极与参比电极之间的电压随时间变化的波形图如图 1所示， 清洗时间 QT= 18秒， 富集时间 FT=36秒，静置时间 JT= 12秒， 扫描时间 ST=6秒； 富集电压和静置电压都为一 1. 3V， 该电压为不随时间变化的恒定电压； 扫描 起始电压为一 1. 3V, 扫描终止电压为一 0. 05V。 刚开始测量时， 得到如图 4 中的谱图 a所示的谱图。 在谱图 a中还能够显示出 Zn、 Cd、 Pb、 Cu的溶出 峰， 其中： Zn的溶出峰高为 9. 62， Cd的溶出峰高为 3.^21， Pb的溶出峰高 为 28. 32， Cu的溶出峰高为 6. 21。对同一样品连续测量 1小时后， 极谱仪的 灵敏度就会明显下降， 得到如图 4中的谱图 b所示的谱图。 在谱图 b中 Zn 的溶出峰明显降低， 其中： Zn的溶出峰高为 1. 13， Cd的溶出峰高为 1. 10， Pb的溶出峰高为 23. 80， Cu的溶出峰高为 5. 81。 此时如果继续采用现有的 阳极溶出伏安法测量 Zn的浓度， 就必须延长富集时间 FT或者对银基汞膜 工作电极进行处理， 否则无法继续进行测量。 . In order to compare the technical effects of the embodiments of the present invention with the existing anodic stripping voltammetry, before introducing the embodiments of the present invention, first use the existing anodic stripping voltammetry to measure Zn, Cd, Pb, Cu concentration. The existing anodic stripping voltammetry includes four steps of cleaning, enrichment, standing and scanning in each test cycle. The instrument uses a polarograph, the sensitivity of the polarograph is selected as 10, and the working electrode of the polarograph uses silver. Mercury based working electrode. The waveform diagram of the time-varying voltage between the anode stripping voltammetry working electrode and the reference electrode is shown in Figure 1. Cleaning time QT = 18 seconds, enrichment time FT = 36 seconds, rest time JT = 12 seconds, scan time ST = 6 seconds; both the enrichment voltage and the rest voltage are 1.3 V, and the voltage is constant and does not change with time. 05V。 Voltage; scan start voltage is a 1.3V, scan end voltage is a 0.05V. At the beginning of the measurement, a spectrum as shown in spectrum a in FIG. 4 was obtained. The dissolution peaks of Zn, Cd, Pb, and Cu can also be displayed in spectrum a. Among them: the dissolution peak height of Zn is 9.62, the dissolution peak height of Cd is 3. ^ 21, and the dissolution peak height of Pb is 28. 32, Cu dissolution peak height is 6.21. After the same sample is continuously measured for 1 hour, the sensitivity of the polarograph will be significantly reduced, and the spectrum shown in spectrum b in FIG. 4 is obtained. In the spectrum b, the dissolution peak of Zn is significantly reduced, wherein: the dissolution peak height of Zn is 1. 13, the dissolution peak height of Cd is 1. 10, the dissolution peak height of Pb is 23. 80, and the dissolution peak height of Cu is 5. 81. At this time, if the existing anodic stripping voltammetry is used to measure the Zn concentration, the enrichment time FT must be extended or the silver-based mercury film working electrode must be processed, otherwise the measurement cannot be continued. .
本发明的实施例是一种采用极谱仪进行的阳极溶出伏安法， 在每一个测 试周期中包括清洗、 富集、 静置、 扫描四个步骤。 极谱仪的工作电极继续使 用前述的经过连续测量 1小时后的银基汞膜工作电极，测量样品也继续使 用前述的测量样品， 极谱仪的灵敏度继续选为 10。 清洗时间 QT=18秒， 富集时间 FT=36秒， 静置时间 JT= 12秒， 扫描时间 ST=6秒， 与前述的现 有的阳极溶出伏安法所采用的时间都相同。 本实施例中工作电极与参比电极 之间的电压随时间变化的波形图如图 3所示， 图 3中富集电压不是在整个富 集时间内恒定不变的， 而是在两段时间内为一个不随时间变化的恒定电压 VI， 在另外一段时间内为一个比电压 VI低的电压 V2。其中， 富集电压在整 个富集时间的前 12秒内为不随时间变化的恒定电压 VI， 电压值为一 L 3V; 从富集时间的第 12秒结束的时刻，富集电压跳变为一个比电压 VI低的电压 V2， 电压 V2是一个方波电压， 该方波电压的电压值为一 2. 2V， 方波的宽度 为 1秒；从富集时间的第 14秒开始，富集电压又变为不随时间变化的恒定电 压 VI， 电压值为一 1. 3V。 在整个富集步骤中， 电压 V2的时间占整个富集时 间的 2. 78%。本实施例在开始测试时， 得到的第一个谱图如图 4中谱图 c所 示。在谱图 c中 Zn、 Cd、 Pb、 Cu的溶出峰比谱图 a和谱图 b中的明显增高， 其中： Zn的溶出峰高为 20. 10， Cd的溶出峰高为 6. 54 ， Pb的溶出峰高为 61. 46， Cu的溶出峰高为 11. 94。 可见， 经过富集电压的变化， 对银基汞膜 工作电极起到了明显的活化作用， 极谱仪的灵敏度有了很大的提高。但 图 4中谱图 c不是一个稳定的谱图，不能直接用于分析计算。经过数次测试 后， 谱图的峰高重复稳定， 得到如图 4中谱图 d所示的谱图。在谱图 d中： Zn的溶出峰高为 11. 60， Cd的溶出峰高为 4. 57， Pb的溶出峰高为 34. 16， Cu的溶出峰高为 7. 79。 An embodiment of the present invention is an anodic stripping voltammetry method using a polarograph, which includes four steps of cleaning, enrichment, standing, and scanning in each test cycle. The working electrode of the polarography apparatus continued to use the foregoing silver-based mercury film working electrode after continuous measurement for 1 hour, and the measurement sample also continued to use the foregoing measurement sample. The sensitivity of the polarography apparatus was continuously selected as 10. The cleaning time QT = 18 seconds, the enrichment time FT = 36 seconds, the standing time JT = 12 seconds, and the scanning time ST = 6 seconds are the same as those used in the conventional anode stripping voltammetry described above. In this embodiment, the waveform of the voltage between the working electrode and the reference electrode as a function of time is shown in Fig. 3. In Fig. 3, the enrichment voltage is not constant during the entire enrichment time, but in two periods. Is a constant voltage VI that does not change with time, and a voltage V2 that is lower than the voltage VI for another period of time. Among them, the enrichment voltage is a constant voltage VI that does not change with time within the first 12 seconds of the entire enrichment time, and the voltage value is one L 3V; from the moment when the 12th second of the enrichment time ends, the enrichment voltage jumps to one The voltage V2 is lower than the voltage VI, and the voltage V2 is a square wave voltage. The voltage value of the square wave voltage is -2.2V, and the width of the square wave is 1 second. From the 14th second of the enrichment time, the enrichment voltage 3V。 It becomes a constant voltage VI that does not change with time, and the voltage value is -1.3V. In the entire enrichment step, the time of the voltage V2 accounts for 2.78% of the entire enrichment time. When the test is started in this embodiment, the first spectrum obtained is shown as spectrum c in FIG. 4. 54 ， The dissolution peaks of Zn, Cd, Pb, Cu in the spectrum c are significantly higher than those in the spectra a and b, wherein: the dissolution peak height of Zn is 20. 10, and the dissolution peak height of Cd is 6. 54 ， The dissolution peak height of Pb is 61.46, and the dissolution peak height of Cu is 11.94. It can be seen that after the change of the enrichment voltage, the active electrode of the silver-based mercury film has been significantly activated, and the sensitivity of the polarograph has been greatly improved. However, the spectrum c in FIG. 4 is not a stable spectrum and cannot be directly used for analysis and calculation. After several tests, the peak height of the spectrum is repeatedly stable, and the spectrum shown in spectrum d in FIG. 4 is obtained. In the spectrum d: the dissolution peak height of Zn is 11.60, the dissolution peak height of Cd is 4.57, and the dissolution peak height of Pb is 34.16, The elution peak height of Cu was 7.79.
将图 4中的谱图 a、 b和 d三个谱图进行比较，可以看出， 极谱仪的工作 电极继续使用前述的经过连续测量 1小时后的银基汞膜工作电极， 测量样 品也继续使用前述的测量样品， 谱图 d中的 Zn、 Cd、 Pb和 Cu的溶出峰 明显高于谱图 a、 b中 Zn、 Cd、 Pb和 Cu的溶出峰。 说明采用本发明后， 对 银基汞膜工作电极起到活化作用， 提高了极谱仪的灵敏度。  Comparing the three spectra a, b, and d in Figure 4, it can be seen that the working electrode of the polarograph continues to use the aforementioned silver-based mercury film working electrode after continuous measurement for 1 hour, and the measurement sample is also Continuing to use the aforementioned measurement samples, the dissolution peaks of Zn, Cd, Pb, and Cu in spectrum d are significantly higher than the dissolution peaks of Zn, Cd, Pb, and Cu in spectra a, b. It is shown that after adopting the present invention, it activates the working electrode of the silver-based mercury film and improves the sensitivity of the polarograph.
谱图 e是将上述同一样品连续加标测定 2— 3次后， 重新取未加标 的样品再次测量得到的谱图。 谱图 e中 Zn的溶出峰高为 12. 01， Cd的溶 出峰高为 4. 57， Pb的溶出峰高为 34. 18， Cu的溶出峰高为 1. 15。  The spectrum e is the spectrum obtained by measuring the same sample for two or three consecutive times, and then re-taking the non-spiked sample. In the spectrum e, the dissolution peak height of Zn is 12.01, the dissolution peak height of Cd is 4.57, the dissolution peak height of Pb is 34. 18, and the dissolution peak height of Cu is 1.15.
将图 4中的谱图3、 b、 d和 e四个谱图进行比较， 可以看出， 在谱图 e 中的 Cu的溶出峰高明显降低。 因此， 经过连续加标测定同一样品 2—3次 处理后的银基汞膜工作电极， 再测定上述同一批海水中样品， 测出的 Cu 的浓度与采用石墨炉原子吸收法测出的浓度基本一致。 说明采用本发明后， 对银基汞膜工作电极起到活化作用的同时， 还能提高阳极溶出伏安法测 量 Cu的准确度。  Comparing the four spectra 3, b, d and e in FIG. 4, it can be seen that the peak height of the dissolution peak of Cu in the spectrum e is significantly reduced. Therefore, after continuous spiking measurement of the silver-based mercury film working electrode of the same sample 2-3 times, and then measurement of the same batch of seawater samples, the measured Cu concentration is basically the same as that measured by the graphite furnace atomic absorption method. Consistent. It is shown that after using the present invention, while activating the working electrode of the silver-based mercury film, it can also improve the accuracy of Cu measurement by anodic stripping voltammetry.

Claims

权 利 要 求 书 Claim
1. 一种阳极溶出伏安法， 在每一个测试周期中包括清洗、 富集、 静置、 3描四个步骤； 其特征是： 在富集步骤中的富集电压和静置步骤中的静置电 E至少有一个在一段或者几段时间内低于一 1.7V。 1. An anodic stripping voltammetry, which includes four steps of cleaning, enrichment, standing, and drawing in each test cycle; characterized in that: the enrichment voltage in the enrichment step and the At least one of the static electricity E is lower than a 1.7V for a period or periods.
2. 根据权利要求 1所述的阳极溶出伏安法， 其特征是： 富集电压或者静 £电压在不同的时间段内电压值不同， 其中在—段或几段时间内为电压 (VI), 在另外一段或者几段时间内为一个比电压 （VI) 低的电压 （V2)。  2. The anodic stripping voltammetry according to claim 1, characterized in that: the enrichment voltage or the static voltage has different voltage values in different time periods, wherein the voltage (VI) is in one or more periods. A voltage (V2) lower than the voltage (VI) for another period or periods.
3. 根据权利要求 2所述的阳极溶出伏安法， 其特征是： 电压 （V2) 在 -1.7V〜一 100V范围内。  3. The anodic stripping voltammetry according to claim 2, characterized in that the voltage (V2) is in a range of -1.7V to -100V.
4. 根据权利要求 3所述的阳极溶出伏安法， 其特征是： 电压 （V2) 在 -1.7V〜一 3V范围内。  The anode stripping voltammetry according to claim 3, wherein the voltage (V2) is in a range of -1.7V to -3V.
5. 根据权利要求 4所述的阳极溶出伏安法， 其特征是： 电压 （V2) 所 ¾·的时间为整个富集时间或者静置时间的 0.00001%〜15%。  5. The anodic stripping voltammetry according to claim 4, characterized in that: the time of the voltage (V2) is 0.00001% to 15% of the entire enrichment time or standing time.
6. 根据权利要求 2、 3、 4或 5所述的阳极溶出伏安法， 其特征是： 电压 (V2) 为不随时间变化的恒定电压。  6. The anode stripping voltammetry according to claim 2, 3, 4 or 5, characterized in that the voltage (V2) is a constant voltage that does not change with time.
7. 根据权利要求 6所述的阳极溶出伏安法， 其特征是： 电压 （V2) 为 ¾ "波。  The anodic stripping voltammetry according to claim 6, characterized in that the voltage (V2) is a ¾ "wave.
8. 根据权利要求 2、 3、 4或 5所述的阳极溶出伏安法， 其特征是： 电压 (V2) 为随时间变化的电压。  The anode stripping voltammetry according to claim 2, 3, 4 or 5, characterized in that the voltage (V2) is a voltage that changes with time.
9. 根据权利要求 8所述的阳极溶出伏安法， 其特征是： 电压 （V2) 为 E弦波的一部分。  The anodic stripping voltammetry according to claim 8, characterized in that the voltage (V2) is a part of the E sine wave.
10. 根据权利要求 8所述的阳极溶出伏安法， 其特征是： 电压 （V2) 为 三角波的一部分。  The anode stripping voltammetry according to claim 8, characterized in that the voltage (V2) is a part of a triangular wave.
11. 根据权利要求 8所述的阳极溶出伏安法， 其特征是： 电压 （V2) 为 弟形波的一部分。  11. The anodic stripping voltammetry according to claim 8, characterized in that the voltage (V2) is a part of a brother wave.
PCT/CN2005/000818 2004-06-18 2005-06-09 Anodic stripping voltammetry WO2005124334A1 (en)

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