1. Electrochemical analysis refers to the application of electrochemical principles and techniques. It is based on the principle of the original battery model to analyze the relationship between the electrode type of the sample and the composition and content of the electrolyte and the electrochemical properties between the two. A type of analytical method. It is now common to use electrochemical workstations to test samples. It is characterized by high sensitivity, good selectivity, simple equipment, convenient operation and wide application range. Electrochemical analysis can be divided into potential method, electrolysis method, conductance method and voltammetry according to the measured electrical signals.

The potential method is an analytical method for determining the content of a substance to be tested by measuring the electromotive force of the electrode. If the content of the analyte is directly calculated according to the measured value of the electrode potential, it is called the direct potential method; if the end point of the titration is determined according to the change of the electrode potential during the titration, it is called potentiometric titration. The electrolysis method is an analysis method for determining the content of the analyte according to the nature of the quantitative deposition of the analyte on the electrode at the time of energization.

The conductance method is based on the principle that the conductivity of the solution is different depending on the solubility of the solute in the electrolyte solution, and the analytical method of measuring the conductivity of the solution to determine the content of the analyte. Voltammetry is an electrochemical analysis method in which a microelectrode is inserted into a solution to be tested, and qualitative or quantitative analysis is performed according to a current-voltage curve of the substance to be tested during electrolysis.

2. Photochemical analysis is a chemical analysis method based on the interaction of energy on a substance, based on the emission of the substance, the absorption of electromagnetic radiation, and the interaction of the substance with electromagnetic radiation. It can be mainly divided into two major categories: spectroscopy and non-spectral methods. The spectroscopy is a method of analyzing the wavelength and intensity of emitted, absorbed or scattered radiation generated by the transition between energy levels in which the radiant energy interacts with the substance without measuring the presence or absence of quantization. There are mainly atomic absorption spectroscopy, atomic emission spectroscopy, atomic fluorescence analysis, infrared spectroscopy and the like. The non-spectral method tests substances based on the volatility of light, mainly spectrophotometry and optical rotation.