Hydrogen sulfide (H2S) is a pervasive gaseous pollutant that emits the characteristic odor of rotten gas, , even at low concentrations. It is generated during various industrial processes, , including petroleum and natural gas refining, , mining operations, , wastewater treatment activities, , and refuse disposal practices. According to statistics from the World Health Organization (WHO ), over 70 occupations are exposed to H2S, rendering it a key monitoring factor in occupational disease detection. Although H2S has legitimate uses in the chemical, , medical, , and other fields, , prolonged exposure to this gas can cause severe damage to the respiratory and central nervous systems, , as well as other organs in the human body. Moreover, , the substantial release of H2S into the environment can lead to significant pollution. This noxious substance has the potential to impair soil, , water, , and air quality, , while disrupting the equilibrium of the surrounding ecosystems. Therefore, , sulfide has become one of the most commonly measured substances for environmental monitoring worldwide. Achieving the stable enrichment and accurate detection of lowlevel H2S is of great significance. Common methods for detecting this gas include spectrophotometry, chemical analysis, gas chromatography, rapid field detection, and ion chromatography. Although these methods provide relatively reliable results, they suffer from limitations such as high detection cost, low recovery, lack of environmental friendliness, and imprecise quantification of lowconcentration H2S. Furthermore, the sampling processes involved in these methods are complex and require specialized equipment and electrical devices. Additionally, approximately 20% of the sulfides in a sample are lost after 2 h in a conventional alkaline sodium hydroxide solution, causing difficulties in preservation and detection. In this study, an accurate, efficient, and costsaving method based on ion chromatography pulse amperometry was developed for H2S determination. A conventional IonPac AS7 (250 mm x4 mm) anionexchange column was employed, and a new eluent based on sodium hydroxide and sodium oxalate was used to replace the original sodium hydroxidesodium acetate eluent. The main factors influencing the separation and detection performance of the proposed method, including the pulse amperage detection potential parameters and integration time, as well as the type and content of additives in the stabilizing solution, were optimized. The results showed that the proposed method had a good linear relationship between 10 and 3 000 mu g/ L, with correlation coefficients ( r 2 ) of up to 0. 999. The limits of detection (S/N S/N = 3) and quantification (S/N= S/N = 10) were 1. 53 and 5. 10 mu g/ L, respectively. The relative standard deviations ( RSDs ) of the peak area and retention time of sulfides were less than 0. 2% ( n = 6). The new method exhibited excellent stability, with up to 90% reduction in reagent costs. Compared with conventional ion chromatographypulse amperometry, this method is more suitable for detecting low concentrations of sulfides in actual samples. Sulfides in a 250 mmol/ L sodium hydroxide 0. 8% (mass fraction) ethylenediaminetetraacetic acid disodium salt solution were effectively maintained for over 10 h. The new stabilizer significantly improved the reliability of both largescale and longterm detection. The recovery of the proposed method was investigated by combining the system with a badgetype passive sampler. This sampling method requires no power devices; ; it is inexpensive, simple to operate, and can realize longterm sampling without the need for skilled personnel. Moreover, it can overcome the influence of shortterm changes in pollutant concentration. The sampling results have high reference value for largescale interventionless pollutant monitoring in ultraclean rooms, museum counters, and other places. The results demonstrated that the recovery of the proposed method was greater than 95% for the blank sample and 80% for the sample plus standard solution. Finally, the newly established method was applied to determine H2S 2 S levels in air samples collected via passive sampling at school garbage stations. The measured results did not exceed the national limit.

Nitroaromatic compounds are used extensively in various fields such as dyes, pesticides, spices, pharmaceuticals, and explosives. However, the residual raw materials of these compounds accumulate in the environment and pose serious risks to human health. Chronic exposure to low concentrations of nitroaromatic compounds can cause anemia, cancer, and organ damage. Currently, Fenton oxidation and natural bioremediation are the processes most often used to eliminate nitroaromatic compounds from environmental water and soil. According to previous research, the presence of inorganic anions such as chloride, nitrite, and nitrate ions in the environmental matrix exerts an inhibitory effect on the biodegradation of nitroaromatic compounds. Furthermore, high nitrate levels in drinking water can lead to the production of nitrosamine carcinogens, which affect ecological safety and human health, in water bodies. Thus, the simultaneous determination of nitroaromatic compounds and chloride, nitrite, and nitrate ions in environmental soil and water matrices is critical for selecting appropriate nitroaromatic compound degradation methods and monitoring surface water quality. Traditional detection methods require two sample pretreatment steps and two instrumental analytical techniques to determine nitroaromatic compounds and inorganic anions in environmental matrices; moreover, these methods are time consuming, labor intensive, and error prone. Therefore, in this study, a method that combines high performance liquid chromatography ( HPLC) and ion chromatography ( IC) was developed to simultaneously detect nitroaromatic compounds and anions in environmental matrices. In this method, sample enrichment was achieved through bulk injection and enrichment column collection, which greatly simplified the pretreatment process. The HPLC instrument was connected to the IC instrument using two six. way valves and an enrichment column. The system operation can be divided into four stages: ( A) sample loading to the quantitative ring, ( B) separation of nitroaromatic compounds and anions, ( C) enrichment of anions in an AG20 column, and ( D) simultaneous determination of nitroaromatic compounds and anions by HPLC and IC, respectively. The time of the anions flowing out of the C-18 column was determined by directly connecting the C-18 column to a conductivity detector. Based on the retention times of the anions, the switching time of the six-way valve was optimized to ensure that the anions completely entered the IC column, thereby ensuring the accuracy of the method. During the chromatographic analysis stage, nitroaromatic compounds were separated and analyzed by HPLC system with a mobile phase composed of potassium phosphate buffer (pH 7. 0) and acetonitrile ( 60 : 40, v / v) at a flow rate of 1. 0 mL / min; in the IC system, the anions were separated and analyzed using a 20 mmol / L sodium hydroxide aqueous solution as the mobile phase under a suppression current of 50 mA. Both anions and nitroaromatic compounds exhibited strong linear correlations within certain concentration ranges, with correlation coefficients greater than 0. 993. The recoveries of the nitroaromatic compounds and anions ranged from 88. 20% to 105. 38% at three spiked levels, with relative standard deviations ranging from 2. 0% to 11. 5%. The contents of six nitroaromatic compounds and three anions in five surface water and five soil samples were determined using the developed method. Although no nitroaromatic compounds were detected in these samples, the three anions were detected at contents ranging from 0. 41 to 55. 3 mg / L in surface water samples, and 0. 56 to 30. 2 mg / kg in soil samples. Methodological validation and actual sample detection demonstrated that the pro. posed method has a high degree of automation, simple operation, good repeatability, high accuracy, wide applicability, and high sensitivity. Thus, this method is suitable for the rapid determination of chloride, nitrite, nitrate ions and nitroaromatic compounds in soil and water and can be extended to the simultaneous determination of inorganic ions and organic matters in other samples.