National University of Singapore Environmental Research Institute, National University of Singapore, T-Lab Building #02-01, 5A Engineering Drive 1, Singapore 117411, Singapore.
National University of Singapore Environmental Research Institute, National University of Singapore, T-Lab Building #02-01, 5A Engineering Drive 1, Singapore 117411, Singapore; Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore; Tropical Marine Science Institute, National University of Singapore, S2S Building, 18 Kent Ridge Road, Singapore 119227, Singapore.
J Chromatogr A. 2018 Oct 26;1573:42-47. doi: 10.1016/j.chroma.2018.08.060. Epub 2018 Sep 5.
Determination of α-dicarbonyl compounds, glyoxal (Gly) and methyl glyoxal (Mgly), in atmospheric fine particulate matter PM (particulate matter with an aerodynamic diameter of less than 2.5 μm) which play vital roles in generating secondary organic aerosols in the ambient air, was carried out by vortex-assisted micro-solid phase extraction (VA-μ-SPE)-liquid chromatography-diode array detection (LC-DAD), with on-sorbent derivatization by 2,4-dinitrophenylhydrazine (DNPH). This is the first time such an approach of combining on-sorbent derivatization and extraction in one step together with LC analysis has been applied to PM. Extraction parameters such as selection of sorbent, extraction time, desorption time and sample volume were optimized using water samples spiked with Gly and Mgly. Under the most favourable conditions, good intra- (1.39%-2.78%) and inter-day (2.29%-6.56%) precision and linearity (ranging between 0.5 and 100 ng mL) along with coefficients of determination 0.998 and 0.997, were determined. The limits of detection were determined to be 0.14 ng mL (derivatized Gly) and 0.15 ng mL (derivatized Mgly) whereas the limits of quantification were 0.47 ng mL and 0.50 ng mL, respectively. The developed method was successfully employed to the determination of Gly and Mgly associated with PM. The latter was collected on glass fiber filters which were immersed in methanol: water (1:1 v/v) for μ-SPE, which was conducted using a sorbent pre-coated with DNPH. The concentrations of the Gly and Mgly were determined to be 0.38 ng m and 0.41 ng m in the sampled ambient air, with relative recoveries of between 69-97%.
采用涡旋辅助微固相萃取（VA-μ-SPE）-液相色谱-二极管阵列检测（LC-DAD），结合 2,4-二硝基苯肼（DNPH）在固相上衍生，测定大气细颗粒物 PM（空气动力学直径小于 2.5μm 的颗粒物）中具有重要作用的α-二羰基化合物（环境空气中生成二次有机气溶胶的关键物质），甲醛（Gly）和甲基乙二醛（Mgly）。这是首次将这种在固相上衍生和萃取一步完成并与 LC 分析相结合的方法应用于 PM。采用水样品对 Gly 和 Mgly 进行加标，优化了萃取参数，如吸附剂的选择、萃取时间、解吸时间和样品体积。在最有利的条件下，确定了良好的日内（1.39%-2.78%）和日间（2.29%-6.56%）精密度以及线性（范围在 0.5 到 100ng/mL 之间），相关系数为 0.998 和 0.997。检测限分别为衍生化 Gly 为 0.14ng/mL 和衍生化 Mgly 为 0.15ng/mL，定量限分别为 0.47ng/mL 和 0.50ng/mL。该方法成功应用于与 PM 相关的 Gly 和 Mgly 的测定。后者收集在玻璃纤维滤纸上，浸入甲醇：水（1：1 v/v）中进行μ-SPE，使用预先涂有 DNPH 的吸附剂进行。在采样的环境空气中，Gly 和 Mgly 的浓度分别为 0.38ng/m 和 0.41ng/m，相对回收率在 69-97%之间。
