title: Hemimicelle capped functionalized carbon nanotubes-based nanosized solid-phase extraction of arsenic from environmental water samples.
abstract: The end functionalization of CNTs can introduce oxygen-containing negatively functional groups such as -COOH, -OH, or -CO on their surface site. If cationic surfactant such as cetyltrimethylammonium chloride (CTAC) was added to the functionalized CNTs, then interactions such as hydrophobic and ionic may lead to formation of hemimicelle/admicelle aggregates on the CNTs, a new kind of adsorbents, namely, the hemimicelle capped CMMWCNTs, is obtained. The application of the hemimicelle capped carbon nanotubes-based nanosized solid-phase extraction (SPE) adsorbents in environmental analysis is reported for the first time using arsenic as model target. The effect of adsorption and desorption conditions for arsenic including the amount of surfactant, initial pH of sample solution, the ultrasonic time of sample solution, the amount of electrolyte, flow rate, eluent and its amount were investigated and optimized prior to its determination by atomic fluorescence spectrophotometry (AFS). Arsenic can be quantitatively retained on the hemimicelle capped CMMWCNTs at pH 5-6 from sample volume up to 500 mL and then eluted completely with 2 molL(-1) HNO(3) in the presence of 10 mgL(-1) CTAC. The method detection limit for arsenic determination with AFS detection was 2ngL(-1), and the relative standard deviation (RSD, n=11) was 5.3% at the 0.5 microgL(-1) level. The recoveries of arsenic in the spiked environmental water samples ranged from 94% to 104.29% with 500 mL of water sample. The proposed method has been applied successfully to the analysis of arsenic in aqueous environmental samples, which demonstrates the hemimicelle capped CMMWCNTs can be an excellent SPE adsorbents for arsenic pretreatment and enrichment from real water samples.
authors.affiliation: College of Chemistry and Chemical Engineering, Southwest University, The Key Laboratory of Eco-environments in Three Gorges Reservoir Region, The Key Laboratory of Luminescence and Realtime Analysis, Ministry of Education; Beibei, Chongqing 400715, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Li
authors.forename: Yuming
authors.initials: Y
authors.lastname: Huang
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Weidong
authors.initials: W
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000032:analysis*; D004573:Electrolytes / Q000737:chemistry; D004785:Environmental Pollutants / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D037742:Nanotubes, Carbon / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D013501:Surface-Active Agents / Q000737:chemistry; D013997:Time Factors; D014465:Ultrasonics; D014867:Water / Q000737:chemistry*
chemical_list: D004573:Electrolytes; D004785:Environmental Pollutants; D008823:Micelles; D037742:Nanotubes, Carbon; D013501:Surface-Active Agents; D014867:Water; D001151:Arsenic