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.

We report here measurements of aerosol black carbon (BC) and aqueous and methanol-extractable brown carbon (BrCaq and BrCme) from a receptor location in the eastern Imlo-Gangetic Plain (IGP) under two aerosol regimes: the photochemistry-dominated summer and biomass burning (BB) dominated post-monsoon. We couple time-resolved measurements of BC and aerosol light absorption coefficients (b(abs)) with time-integrated analysis of BrC UV-Vis and fluorescence characteristics, along with measurements of total and water-soluble organic carbon (OC and WSOC), and ionic species (NH4+,K+, NO3-. In the BB regime, BC and its BB-derived fraction (BCBB) increased by factors of 3-4 over summertime values. In comparison, b(abs_365_me) and b(abs_365_me ()absorption coefficients of BrCaq and BrCme at 365 nm) increased by a factor of 5 (9.7 +/- 7.8 vs 2.1 = 1.4 Mm(-1)) and 2.5 (172 +/- 9.0 vs 6.9 = 2.9 Mm(-1)), respectively, in the BB period over summer, and were highly correlated (r 0.82-0.87; p < 0.01) with the BB-tracer nss-K+. The wavelength dependence of b(abs_BrC) (angstrom ngstrom exponent: 5.9-6.2) and the presence of characteristic fluorescence peaks at 420-430 nm suggested presence of humiclike substances (HULIS) in the aged BB aerosol, while significant association between BrCaq and NO3- (r 0.73; p < 0.01) possibly indicated formation of water-soluble nitroaromatic compounds. BrCaq contributed 55% to total BrC absorption at 300-400 nm while that for the water-insoluble component (WI-BrC) increased from 41% at 340 nm to -60% at 550 nm, suggesting formation of water-insoluble polycyclic aromatic hydrocarbons (PAH5) and/or N-PAHs. Mass absorption efficiencies at 365 nm (MAE 365 ) of BrC aq and BrCaq in the BB regime (0.95 +/- 0.45 and 1.17 +/- 0.78 m(2) g respectively) were in line with values expected from photobleaching of BB source emissions after transport to the eastern IGP. Overall, BrCaq and BrCme were significant components of light absorbing aerosol in the BB regime, with contributions of 9 +/- 5% and 16 = 7%. respectively, to radiative forcing vis-a-vis BC in the 300-400 nm range. (C) 2020 Elsevier B.V. All rights reserved.