| Carbon nanotube modified electrodes is widely used in analytical chemistry andenvironmental detection because the carbon nanotube modified electrode has large specificsurface area, good catalytic activity, porosity and surface containing many functional groupsand other special properties allow it to reduce substrate potential, lower limit of detection,increase the current response and can generate unique catalytic effect on electrochemicalreaction of certain analytes.Mercury film electrode has a very thin film,large work area/volume ratio, strongmechanical stability, lower mercury/mercury salt consumption,can be prepared intocomposite mercury film electrode.They can facilitate enrichment and separation of metal ionsin the film diffusion, accelerate the stirring rate to improve enrichment efficiency, make fulluse of structure of modifier, improve selectivity and sensitivity of the detected matter, reducethe pollution of the environment.With the advantages of solid electrode and the metal mercury electrode, the mercury filmelectrode also overcomes the shortcoming of HMED. The research work of this thesis is asfollows:（1） Determination of copper content in agricultural products by differential pulse anodicstripping voltammetryWith glassy carbon electrode as the base, a mercury film electrode was prepared by themethod of pre-plating mercury film. The electrodes have strongly mechanical stability, highsensitivity. Copper contents of13kinds of agricultural products were determined bydifferential pulse anodic stripping voltammetry. The effect of the bottom liquid, enrichmentpotential, enrichment time and other conditions were discussed on the stripping current. Underthe optimized experimental conditions, the stripping peak current and the concentration ofcopper ions have good linear relationship in1×10-8～4×10-6mol/L, Linear regressionequation: ip（μA）=4.5631+50.64908C（μmol/L）, R2（correlation coefficient）=0.9991.The copper contents in agricultural products were determined and were made a comparisonwith flame atomic absorption spectrometry. The recovery rates range from94%to107%.（2） Study of the electrochemical behavior of hydroquinone in the multi-walled carbon nanotube modified electrodeWith glassy carbon electrode as the base and multi-walled carbon nanotubes as modifier,multi-walled carbon nanotubes modified electrode was prepared by dropping the coatingmethod.Electrochemical behavior of hydroquinone on it was investigated by using cyclicvoltammetry and differential pulse voltammetry.The influences of acidity, modification,scanning speed and other factors on the volt-ampere characteristic was discussed to obtain amore optimized experimental conditions. Under the optimized experimental conditions,thereductive peak current of HQ was increased linearly with concentration in the rang of5×10-6～2×10-4mol/L with the detection limit of2.7×10-6mol/L（S/N=3）by using differential pulsevoltammetry. Linear regression equations: ip（μA）=10.09439+0.27661c （μmol/L）, R2=0.9993. The wastewater of simulated developer：a variety of metal ions and the sameconcentration of catechol does not affect the determination of hydroquinone but the sameconcentration of resorcinol seriously affect it.10-4mol/L hydroquinone was measured15times, RSD=2.5%, so the electrode is reproducible. Spiked recovery of the simulateddeveloper’wastewater is94%～104%.The result is satisfactory and can be used for thedetermination of HQ in the wastewater of developer.（3） The determination of hydroquinone on multi-wall carbon nanotube/titania modifiedelectrode10mg titanium dioxide nanotubes and2mg multi-walled carbon nanotubes was dispersedin10mL chitosan solution whose mass fraction was0.5%,then modifier solution was prepared.With glassy carbon electrode as the base, modified electrode was prepared by dropping thecoating method. Electrochemical behavior of hydroquinone on it was investigated by usingcyclic voltammetry and differential pulse voltammetry. The results show that: the reversibilityof the electrode reaction is very good.Under the optimized experimental conditions,the peak current of HQ was increasedlinearly with concentration in the rang of6×10-5～1.2×10-3mol/L with the detection limit of1.2×10-5mol/L（S/N=3）by using differential pulse voltammetry. Linear regression equation: ip（A）=0.12844+5025.89463C（mol/L）, R2=0.9991（S/N=3）.10-4mol/L hydroquinone was measured16times, RSD=2.3%. Spiked recovery of the simulated developer’wastewater is92%～108%.The result is satisfactory.（4） Determination of hydroquinone in chitosan/nanotubes modified carbon pasteelectrodeWith carbon paste electrode as the base, chitosan/titania modified electrode was prepared.Electrochemical behavior of hydroquinone was studied by means of cyclic voltammetry andlinear sweep voltammetry. In this electrode, the peak current of hydroquinone increaseobviously. The electrode reaction mechanism of hydroquinone was studied. A variety of factorseffect on electrochemical signals were discussed, such as supporting electrolyte, acidity,deposition time, deposition potential and sweep rate. In the same experimental conditions,concentration and peak current of hydroquinone was a good linear relationship from5×10-5to2×10-3mol/L with the detection limit was5×10-6mol/L. The linear regression equation wasip（μA）=0.6568+18.4656C （μmol/L）,R2=0.9998.10-4mol/L hydroquinone was measured12times, RSD=4.9%. Spiked recovery of the simulated developer’wastewater is91%～103%.The result is satisfactory. |
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