title: Combined dispersive solid-phase extraction-dispersive liquid-liquid microextraction-derivatization for gas chromatography-mass spectrometric determination of aliphatic amines on atmospheric fine particles.
abstract: Short-chain aliphatic amines are ubiquitous in the atmospheric environment. They play an important role in the formation and growth of atmospheric particles. As such, there is a pressing need to monitor these particle-bound compounds present at trace quantities. The present work describes an efficient, one-step microextraction technique for the preconcentration and detection of trace levels of 10 aliphatic amines on fine particles (particulate matter of 2.5μm or less (PM2.5)) in the atmosphere. After extraction of amines from particles in acidified water samples, carbon-based sorbents (in dispersive solid-phase extraction mode), and vortex agitation were utilized for simultaneous derivatization-extraction and dispersive liquid-liquid microextraction. The approach significantly increased the recoveries and enrichment of the amine derivatives. This one-step, combined technique is proposed for the first time. Several influential factors including type and concentration of derivatization reagent (for gas chromatographic separation), type of buffer, sample pH, types and volumes of extraction and disperser solvents, type and amount of sorbent, vortex time and temperature, desorption solvent type and volume, and salt content were investigated and optimized. Under the optimum conditions, high enrichment factors (in the range of between 307 and 382) and good reproducibility (relative standard deviations, below 7.0%, n=5) were achieved. The linearity ranged from 0.1μg/L-100μg/L, and from 0.5μg/L-100μg/L, depending on the analytes. The limits of detection were between 0.02μg/L (corresponding to ∼0.01ng/m3in air) and 0.09μg/L (corresponding to ∼0.04ng/m3in air). The developed method was successfully applied to the analysis of PM2.5samples collected by air sampling through polytetrafluoroethylene filters. The concentration levels of amines ranged from 1.04 to 4.16ng/m3in the air sampled.
authors.affiliation: National University of Singapore Environmental Research Institute, T-Lab Building #02-01, 5A Engineering Drive 1, Singapore 117411, Singapore.
authors.forename: Seyed Mohammad
authors.initials: SM
authors.lastname: Majedi
authors.affiliation: National University of Singapore Environmental Research Institute, 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, 18 Kent Ridge, Singapore 119227, Singapore. Electronic address: chmleehk@nus.edu.sg.
authors.forename: Hian Kee
authors.initials: HK
authors.lastname: Lee
mesh_terms: D000588:Amines / Q000032:analysis* / Q000737:chemistry*; D001272:Atmosphere / Q000737:chemistry; D002021:Buffers; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D052638:Particulate Matter / Q000737:chemistry; D015203:Reproducibility of Results; D052617:Solid Phase Microextraction / Q000379:methods*; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D000588:Amines; D002021:Buffers; D052638:Particulate Matter; D012997:Solvents
keywords: Aliphatic amines; Atmospheric particles; Derivatization; Dispersive liquid–liquid microextraction; Dispersive solid-phase extraction; Reduced graphene oxide