title: Online coupling of in-tube solid-phase microextraction with direct analysis in real time mass spectrometry for rapid determination of triazine herbicides in water using carbon-nanotubes-incorporated polymer monolith.
abstract: Online coupling of in-tube solid phase microextraction (IT-SPME) with direct analysis in real time mass spectrometry (DART-MS) was realized for the first time and applied in the analysis of triazine herbicides in lake water and orange juice. We incorporated single-wall carbon nanotubes (SWNTs) into a polymer monolith containing methacrylic acid (MAA) and ethylene dimethacrylate (EDMA) to form a novel poly(methacrylic acid-co-ethylene dimethacrylate-co-single wall carbon nanotubes) (poly(MAA-EDMA-SWNT)) monolith, which was then used in IT-SPME for enrichment of six triazine herbicides from water samples. With the online combination of IT-SPME with DART-MS, the analytes desorbed from the monolith were directly ionized by DART and transferred into MS for detection, thus rapid determination was achieved. Compared with regular DART-MS method, this online IT-SPME-DART-MS method was more sensitive and reproducible, because of the IT-SPME procedures and the isotope-labeled internal standard used in the experiment. Six triazine herbicides were determined simultaneously using this method with good linearity (R(2) > 0.998). The limit of quantification (signal-to-noise ratio of S/N = 10) of the six herbicides were only 0.06-0.46 ng/mL. The proposed method has been applied to determine triazine herbicides in lake water and orange juice, showing satisfactory recovery (85%-106%) and reproducibility (relative standard deviation of RSD = 3.1%-10.9%).
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Xianjiang
authors.initials: X
authors.lastname: Li
authors.forename: Ze
authors.initials: Z
authors.lastname: Li
authors.forename: Yiding
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Bai
authors.forename: Huwei
authors.initials: H
authors.lastname: Liu
mesh_terms: D006540:Herbicides / Q000032:analysis*; D013058:Mass Spectrometry; D037742:Nanotubes, Carbon; D010573:Pesticide Residues / Q000032:analysis*; D011108:Polymers; D052617:Solid Phase Microextraction; D014227:Triazines / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
chemical_list: D006540:Herbicides; D037742:Nanotubes, Carbon; D010573:Pesticide Residues; D011108:Polymers; D014227:Triazines; D014874:Water Pollutants, Chemical