Determination of Methylamines and Methylamine-N-oxides in Particulate Matter Using Solid Phase Extraction Coupled with Ion Chromatography / 分析化学

ABSTRACT

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 (13,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.