摘要：
建立了测定大气颗粒物中氧化三甲胺、一甲胺、二甲胺和三甲胺的固相萃取离子色谱的分析方法.选取20 mL 甲醇-水(1:3,V/V)混和液,超声提取石英滤膜,重复提取2次.提取结束后,合并3次提取液共60 mL,上样到固相萃取设备.使用Agilent AccuBond C18为固相萃取柱富集提取液中的一甲胺、二甲胺、三甲胺和氧化三甲胺.采用0.5 mL乙腈洗脱萃取柱上的甲胺类物质.洗脱后,向溶液中加入1.5 mL去离子水定容,离子色谱定量分析.用阳离子色谱柱PRP X-200 (250 mm × 4.1 mm,10 μm) 为分离柱,以3%(V/V)乙腈和5 mmol/L HNO3为淋洗液,流动相流速1.0 mL/min,柱温箱温度25°C,30 min内4种胺类物质完全分离.方法线性范围为0.45 ~1000 μg/kg,精密度在2% ~4%之间,检出限为0.09 ~0.14 μg/kg (0.002 ~0.003 μg/m3),加标回收率大于90%.将本方法应用于北京市沙尘和霾天气的细颗粒样品分析中,三甲胺和氧化三甲胺的浓度分别为0.01~0.08 μg/m3和0.02~0.14 μg/m3.%A novel method for determination of methylamines and methylamine-N-oxides in fine particles using solid phase extraction (SPE) coupled with ion chromatography (IC) was developed. The experimental conditions including solid phase extraction and chromatographic condition were optimized. The quartz filter loaded with particulate matter (PM) samples was ultrasonically extracted with 20 mL of methanol and water (1:3,V/V) mixture and the extraction process repeated for another 2 times. After the extraction, a total of 60 mL of extraction solvent was dropped into the extraction equipment in solid phase column. The Agilent AccuBond C18was chosen for enriching the methylamine,dimethylamine,trimethylamine and trimethylamine-N-oxide in fine particles. Under the optimum conditions, the target species on Agilent Accu Bond C18were washed by 0. 5 mL of acetonitrile solution and then concentrated into a constant volume (2 mL) before injecting into IC for analysis. A 250 mm×4 mm id PRP X-200 column was used for the separation of analytes at the temperature of 25oC. The mobile phase was a mixture of acetonitrile solution (3%, V/V) and nitric acid (5 mmol/L) with the flow rate being kept at 1 mL/min. The four aliphatic amine species were fully resolved and the separations were completed within 30 min. The linearity of the four compounds ranged from 0.45 to 1000 μg/kg with the precisions of 2%-4% and the detection limits of 0.002-0.003 μg/m3. The recoveries of four aliphatic amine species in real environmental samples were higher than 90%. This method was successfully applied to the analysis of real fine particle samples collected at Beijing. The concentrations of trimethylamine and methylamine-N-oxides were in the range of 0.01-0.08 μg/m3and 0.02-0.14 μg/m3for Beijing dust and haze samples,respectively.
