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During the desulfurization process, the analysis of the components in the desulfurization solution plays a role in supporting and guiding production; it serves as the eyes and ears for proper operation. Therefore, when selecting methods for analyzing this solution, it is essential to ensure speed, accuracy, and the use of small sample sizes. Standardization and accuracy are always the essence of analytical work. Through research on the analysis of desulfurization solutions in recent years, the importance of these aspects is evaluated by examining the relevant testing items. The analysis of the desulfurization solution in wet desulfurization mainly includes the following items: the pH value, OPR value, total alkalinity, total iron content, and the analysis of by-products (sodium thiosulfate, sodium sulfate) in the desulfurization solution. Below, the common issues in each type of analysis are listed one by one, along with a brief analysis of the importance of each analysis item. 1. The pH value of the solution increases as the total alkalinity rises, and it also changes with alterations in other cations and anions present in the solution. However, the key factor is the equivalent ratio of sodium bicarbonate to sodium carbonate. When the total concentration of sodium ions in the solution remains constant, a higher concentration of carbon dioxide leads to an increase in the mole ratio of sodium bicarbonate, thereby reducing the pH value. Therefore, it is best to keep the pH value between 8.0 and 8.5; too low a pH value hinders the absorption of hydrogen sulfide, while too high a pH value causes the formation of by-products, reduces oxygen absorption, and also hinders the aggregation of sulfur. The pH value is determined using a pH meter, and before using such a meter, it needs to be calibrated. Generally, when used continuously, the pH meter should be calibrated once a day. However, many manufacturers calibrate their pH meters only once a week or once a month, which results in large errors in the measured pH values. This prevents an accurate representation of the actual pH level of the desulfurization solution, and thus makes it impossible to monitor production properly. Therefore, when using a pH meter continuously, it must be calibrated daily. 2. ORP value: The ORP value refers to the potential of the desulfurization solution, and it reflects the redox capacity of the solution. It also gives an indication of the ratio between Fe2+ and Fe3+. This value should be maintained between -125 mV and -250 mV. An excessively high ORP value can lead to the formation of double salts, while an excessively low value can cause the catalyst to become deactivated, reducing its oxidation capacity; in some cases, FeS precipitates may even form. Therefore, regularly measuring the ORP value allows for a quick assessment of the performance of the desulfurization solution. ORP is measured using a potentiometric agent; the potentiometer works in the same way as for pH measurement, and may need to be calibrated daily to maintain measurement stability. 3. Total alkalinity: The determination of total alkalinity relies on acid-base neutralization reactions; a standard sulfuric acid solution is used for titration in the presence of an indicator, thereby allowing the calculation of the amounts of sodium carbonate and sodium bicarbonate. From this, the total alkalinity of the desulfurization solution can be determined. The total alkalinity is generally maintained between 0.3 and 0.6. Keeping it at a lower level is highly beneficial for maintaining stable operating conditions, reducing the formation of by-products, lowering resistance, and decreasing the amount of material carried away during regeneration. The importance of determining total alkalinity is self-evident; the addition of alkalis provides guidance and is directly related to production costs. 4. The total iron complexation desulfurization system uses Fe as a catalyst, and the iron ion content is an important parameter. Iron ions are inevitably lost during the production process; if their concentration is too low, hydrogen sulfide in the gas cannot be completely removed, failing to meet the purification requirements. Furthermore, if the total iron concentration is too low, Fe3+ will be reduced to Fe2+ to an excessive extent, which may affect the regeneration process and create a vicious cycle that leads to the collapse of the entire system. Therefore, regular testing of total iron is essential, and atomic absorption spectroscopy is recommended for greater accuracy. From the perspective of salt formation science, the generation of by-products is inevitable in the wet oxidation method for desulfurization; in other words, it is an inherent phenomenon. No matter what desulfurizing agent is used, it is impossible to eliminate or prevent the formation of by-products. For example: 2HS- + 2O2 == H2O + S2O32-, and 2S2O32- + 5O2 == 4SO42-. Of course, when high-quality and efficient iron-based complexing agents are used for desulfurization, hydrogen sulfide reacts rapidly with these agents, preventing HS- from coming into contact with oxygen and thus avoiding any peroxidation reactions, resulting in almost no by-products. However, the detection of by-products indirectly reflects whether the system is operating stably; therefore, it is essential to regularly measure the content of by-products in the desulfurization agent. Behind each testing item are direct economic costs, and to put it more seriously, it has a direct impact on production safety. Errors are an inevitable and objective reality; they can occur at every step of the measurement process, affecting the accuracy of the analytical results. Therefore, analysts must not only conduct measurements on the samples but also, based on actual requirements, provide a reasonable assessment and accurate judgment of the reliability and precision of the analysis results. They should also identify the causes of errors and their patterns, take effective measures to reduce such errors, and draw lessons from experience to continuously improve the accuracy of analyses, so as to make timely adjustments and ensure the smooth progress of production. The testing of various components in the desulfurization solution is complementary to one another, as there is a close connection between them. Let’s use data to draw lessons and ensure the safe and stable operation of production processes.