Application of NaClO-treated multiwalled carbon nanotubes as solid phase extraction sorbents for preconcentration of trace 2,4-dichlorophenoxyacetic acid in aqueous samples.
Multiwalled carbon nanotubes functionalized by oxidation of original multiwalled carbon nanotubes with NaClO were prepared and their application as solid phase extraction sorbent for 2,4-dichlorophenoxyacetic acid (2,4-D) was investigated systemically, and a new method was developed for the determination of trace 2,4-D in water samples based on extraction and preconcentration of 2,4-D with solid phase extraction columns packed with NaClO-treated multiwalled carbon nanotubes prior to its determination by HPLC. The optimum experimental parameters for preconcentration of 2,4-D, including the column activating conditions, the amount of the sorbent, pH of the sample, elution composition, and elution volume, were investigated. The results indicated 2,4-D could be quantitatively retained by 100 mg NaClO-treated multiwalled carbon nanotubes at pH 5, and then eluted completely with 10 mL 3:1 (v/v) methanol-ammonium acetate solution (0.3 mol/L). The detection limit of this method for 2,4-D was 0.15 μg/L, and the relative standard deviation was 2.3% for fortified tap water samples and 2.5% for fortified riverine water sample at the 10 μg/L level. The method was validated using fortified tap water and riverine water samples with known amount of 2,4-D at the 0.4, 10, and 30 μg/L levels, respectively.
School of Chemistry and Environment, South China Normal University, Guangzhou, Guangdong, P. R. China.
Ping
P
Lu
Dayi
D
Deng
Xiaodan
X
Ni
D015084:2,4-Dichlorophenoxyacetic Acid / Q000737:chemistry / Q000302:isolation & purification*; D000327:Adsorption; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000737:chemistry / Q000302:isolation & purification*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D012973:Sodium Hypochlorite / Q000737:chemistry; D052616:Solid Phase Extraction / Q000295:instrumentation / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*
D006540:Herbicides; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; D015084:2,4-Dichlorophenoxyacetic Acid; D012973:Sodium Hypochlorite