| 引用本文: | 刘智艺，王新锋，李敏，侯可勇，王一峰.2023.HILIC/LC-MS直接分离测定大气颗粒物中的15种有机胺[J].地球环境学报,14(2):229-241 |
| LIU Zhiyi, WANG Xinfeng, LI Min, HOU Keyong, WANG Yifeng.2023.Direct determination of fifteen amines in fine particles by HILIC/LC-MS[J].Journal of Earth Environment,14(2):229-241 |
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| HILIC/LC-MS直接分离测定大气颗粒物中的15种有机胺 |
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刘智艺，王新锋，李敏，侯可勇，王一峰
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1. 山东大学 环境研究院，青岛 266237
2. 山东大学 化学与化工学院，济南 250100
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| 摘要: |
| 本文建立了一种基于亲水作用液相色谱柱（HILIC）和液相色谱-质谱联用（LC-MS）的大气颗粒物有机胺的直接测定方法。颗粒物样品经甲醇提取、富集、浓缩后，对不同色谱柱与分析条件进行测试、对比，发现HILIC色谱柱可有效分离有机胺类化合物，高浓度以及低pH值的缓冲溶液可缩短大部分有机胺的保留时间，而流动相中有机相比例增加会延长保留时间。优化的HILIC/LC-MS分析方法可同时测定11种脂肪胺、2种脂环胺、1种芳香胺及1种醇胺，结合内标的有机胺标准曲线的线性相关系数R 2为0.991—0.999。本方法的检出限（S/N=3）为0.59—75.46 ng·mL−1，加标回收率为59%—92%，具有较高的精密度。该方法初步应用于青岛冬季大气细颗粒物样品中有机胺的测定，为大气有机胺的深入研究提供了方法参考与技术支撑。 |
| 关键词: 有机胺 测定 HILIC 液相色谱-质谱联用仪 颗粒物 |
| DOI：10.7515/JEE222044 |
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| 基金项目:山东省自然科学基金项目（ZR2020YQ30）；国家重点研发计划（2020YFF01014503）；山东大学基本科研业务费（2020QNQT012） |
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| Direct determination of fifteen amines in fine particles by HILIC/LC-MS |
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LIU Zhiyi, WANG Xinfeng, LI Min, HOU Keyong, WANG Yifeng
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1. Environment Research Institute, Shandong University, Qingdao 266237, China
2. School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
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| Abstract: |
| Background, aim, and scope Amines, ammonia derivatives with at least one hydrogen atom substituted by alkyl or aryl groups, are an important kind of nitrogen-containing organic compounds in the tropospheric atmosphere. Amines in fine particles constitute a significant fraction of secondary organic aerosols and have adverse effects on air quality and human health. However, due to the relatively high volatility, strong polarity, and low environmental concentration of low molecular weight amines, they are subjected to great difficulty in the accurate determination of their atmospheric abundances. So far amines have been measured in ambient aerosol particles by several techniques, including ion chromatography (IC), gas chromatography (GC), and high-performance liquid chromatography (HPLC). However, the determination with IC was limited to the low separation efficiency and resolution, while GC and HPLC were generally mandatory to use derivatization techniques to improve the separation efficiency and the detection limits. Due to derivatization processed could bring extra uncertainty on the determination of amines, in this study, a derivatization- free determination method based on LC-MS was developed to qualitatively and quantitatively measure particulate amines. Materials and methods The amine standards and the reagent chemicals in this study were ordered from Sigma-Aldrich (USA), AccuStandard (USA), Supelco (USA), TCI (Japan), and ALAF (USA). Particulate matters were collected on quartz fiber filters (Pall, USA) at a flow rate of 100 L·min−1 by a medium-volume fine particulate matter sampler from a rural site in coastal Qingdao. Samples were extracted with methanol, enriched and concentrated for qualitative and quantitative analysis. Amines in solutions were analyzed by using UHPLC (Ultimate 3000, Thermo Scientific, USA) coupled with a quadrupole mass spectrometer (MS, ISQ EC, Thermo Scientific) detector equipped with electrospray ionization (ESI) source. The separation of different amine compounds was performed with a hydrophilic interaction liquid chromatography column (HILIC, 2.1 mm×150 mm, 3.5 µm particle size, Merck SeQuant). The experiment investigated the effects of multiple chromatographic factors (e.g., organic solvent content in eluent, column temperature, flow, inject volume, salt concentration, and pH) on the retention of amines. Individual standards were used to identify the specific amines based on the retention time in the spectrum, and the gradient standard mixtures and Isotopic internal standard were used to obtain multi-point standard curves for the quantification of the 15 amines. Results The HILIC column could effectively separate most amine compounds. The retention time of amines increased as the mobile phase pH increased from 3.2 to 6.2 and decreased significantly as the salt concentration increased from 5 to 20 mmol·L−1. In addition, when the organic solvent content increased, increased retention time was observed for most amines. In the optimized analyzing method based HILIC/LC-MS, sample solution of 4 µL was directly injected into the UHPLC-MS without derivatization. The column temperature was set at 40℃ and the flow rate was 0.2 mL·min−1. The mobile phase consisted of methanol and 20 mmol·L−1 ammonium formate in deionized water. Fifteen amines were determined in this study by using the HILIC/LC-MS method, including eleven aliphatic amines, alcohol amine, two alicyclic amines, and aromatic amine. The contents of amines were quantified by using multipoint calibration curves in combination with internal standard and the correlation coefficients were 0.991—0.999. In addition, the average concentration of total amines in PM2.5 samples was approximately 120 ng·m−3 and dimethylamine was the most abundant species. Discussion The results show that the developed HILIC/LC-MS achieves the direct determination of fifteen amines with the limits of detection from 0.59 to 75.46 ng·mL−1 and the recovery rates of the fifteen amines range from 59% to 92%. The precision of the analytical method was substantially good, with the relative standard deviations for all standards less than 10%. Compared to the previous studies, the present method displays better or similar detection limit, recovery, and precision. Therefore, it is suitable for qualitative and quantitative analysis of atmospheric amines in the particle phase or even in the gas phase. Moreover, due to the omission of derivatization step, the fast pretreatment process is subjected to shorter treatment time and lower treatment cost. However, further modifications are needed to improve the limit of detection and recovery rates of several amines and other relatively abundant amines can be tested to simultaneously detect. Conclusions A HILIC/LC-MS method was developed and successfully applied to directly and simultaneously determine fifteen amines in atmospheric particulate matters. It is reproducible, accurate, stable, sensitive, and significantly simplify the pretreatment process, which provides technical support for the further studies on amines. Recommendations and perspectives The optimized method provides methodology references for the detection of amines in various fields (e.g., water, soil, food, and materials). In the future, the determination method can be further improved by changing the mobile phase conditions to detect more potential species. |
| Key words: amines determination HILIC LC-MS particulate matter |
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