What do the various types of chromatography refer to?

What is a few spectra? Is the author referring to polarography? Potentiometry is a current-voltage graph obtained by using a potentiometer to analyze solutions; it can be found on Baidu and many forums. 1. Polarographic catalytic wave: The polarographic catalytic wave is a method developed on the basis of electrochemistry and chemical kinetics, aimed at improving the sensitivity and selectivity of potentiometric analysis. It has high sensitivity, with a minimum detection limit of 10-9 to 10-11 mol.L-1; it is less affected by the presence of other elements and exhibits good selectivity, making it an excellent method for trace analysis. Polarographic catalytic waves are of two types: one is the parallel catalytic wave, and the other is the hydrogen catalytic wave. (1) Parallel catalytic wave: The parallel catalytic wave is generated because the electroactive substance O is reduced to R at the electrode; R then reacts with another substance Z (an oxidant) present in the solution, being oxidized to form O. The newly formed O is subsequently reduced at the electrode. By repeating this process, the current **increases**. The reaction is as follows: E (electrode reaction) C (chemical reaction). It is worth noting that throughout the entire reaction, the concentration of substance O actually does not change; it is substance Z that is consumed. Substance O acts as a catalyst; its presence facilitates the reduction of Z. The current generated in this way is called the catalytic current. The catalytic current is proportional to the concentration of catalyst O, and can be used to determine the concentration of substance O. For example, the parallel catalytic wave of titanium(IV) in the oxalic acid and potassium chlorate system: Ti(IV) – oxalic acid + e- → Ti(III) – oxalic acid; Ti(III) – oxalic acid + ClO4- → Ti(IV) – oxalic acid + Cl- + others. Oxalic acid acts as a chelating agent, while potassium chlorate serves as an oxidizing agent; this catalytic wave can be used to determine titanium concentrations of 1×10-10 mol.L. For this type of catalytic current at the dropping mercury electrode, the equation is: ic = 0.51FD1/2m2/3t2/3k1/2c01/2c (11–18). Here, ic represents the catalytic current, k is the rate constant of the chemical reaction, c0 is the concentration of the oxidant, and the meanings of the other symbols remain the same as before. Under certain conditions, ic=Kc; this is the basis for the quantitative analysis of parallel catalytic waves. (II) Hydrogen catalytic wave: Hydrogen exhibits a high overpotential at the mercury drop electrode, and its deposition potential in acidic solutions is below -1.20 V. However, when certain trace substances are present in the solution, they are easily reduced and deposit on the surface of the dropping mercury, altering the properties of the electrode surface. This reduces the overpotential of hydrogen at the mercury drop electrode, allowing hydrogen ions to be reduced at a lower overpotential and thus forming a hydrogen catalytic wave. In the experiment, tiny bubbles can be observed on the surface of the mercury drop electrode. Platinum group elements can generate hydrogen catalytic waves in dilute acid solutions; as the concentration of platinum ions increases, the potential of the hydrogen wave shifts to more positive values and the current increases. Regarding the mechanism of such catalytic waves, it is believed that after trace amounts of platinum chloride are reduced on the mercury drop electrode, the platinum atoms do not form an amalgam but instead deposit on the surface of the mercury drop. This modifies the mercury drop electrode into a microelectrode similar to a platinum electrode. The overpotential for hydrogen ions at the platinum electrode is much lower than that at the mercury drop electrode; as a result, hydrogen ions are catalyzed by the platinum atoms deposited on the surface of the mercury drop and are reduced at more positive potentials, thereby generating a hydrogen catalytic wave. II. Pulse Polarography Pulse Polarography is a new polarographic technique developed to overcome the effects of charging current and capillary noise current in conventional polarography. It features high sensitivity and strong resolution, making it the most sensitive method among polarographic techniques. (1) Basic principle: Pulse polarography is a polarographic method in which, on top of a slowly varying direct current voltage, a small-amplitude periodic pulse voltage is applied at the later stage of the growth of each drop of mercury on the mercury drop electrode, and the electrolytic current is measured at the end of the pulse voltage (Figure 11–15). Depending on the method of applying voltage, pulse polarography is divided into conventional pulse polarography and differential pulse polarography. (a) Excitation signal (b) Conventional pulse polarogram. In conventional pulse polarography, the pulse amplitude increases linearly over time; during the intervals between pulses, the potential remains equal to the initial potential. A current sample is taken 20 ms before each pulse disappears, at which point the charging current begins to decay toward zero, and the capillary noise current also decays rapidly. After recording the resulting electrolytic current, a polarogram similar to that obtained by conventional polarography was obtained.

I really don’t know what \"ji pu\" means

In hydrogen peroxide production plants, when it comes to analytical instruments, chromatography can be used, usually in the form of online gas chromatography. As for what a few spectra are, only the original poster and the ghost know.