title: Evaluation of graphene-based sorbent in the determination of polar environmental contaminants in water by micro-solid phase extraction-high performance liquid chromatography.
abstract: A facile method of extraction using porous membrane protected micro-solid phase extraction (μ-SPE) with a graphene-based sorbent followed by high performance liquid chromatography-ultraviolet detector was developed. The reduced graphene oxide (r-GO) (1mg), synthesized from graphite oxide, was enclosed in a polypropylene bag representing the μ-SPE device, which was used for the extraction of estrogens such as estrone, 17β-estradiol, 17α-ethynylestradiol and diethylstilbestrol in water. The r-GO obtained was identified and characterized by Fourier transform infrared, transmission electron microscopy, scanning electron microscopy and thermogravimetric analysis. The sorbent was loaded with sodium dodecyl sulfate by sonication to prevent agglomeration in aqueous solution. With this method, low limits of detection of between 0.24 and 0.52 ng L(-1) were achieved. For estrogen analysis a linear calibration range of 0.01-100 μg L(-1) was obtained, with the coefficients of determination (r(2)) higher than 0.992. This proposed method was successfully applied to determine estrogens in water.
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore; National University of Singapore Environmental Research Institute, T-Lab #02-01, 5A Engineering Drive 1, Singapore 117411, Singapore.
authors.forename: Nyi Nyi
authors.initials: NN
authors.lastname: Naing
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore; National University of Singapore Environmental Research Institute, T-Lab #02-01, 5A Engineering Drive 1, Singapore 117411, Singapore.
authors.forename: Sam Fong Yau
authors.initials: SF
authors.lastname: Li
authors.affiliation: Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore; National University of Singapore Environmental Research Institute, T-Lab #02-01, 5A Engineering Drive 1, Singapore 117411, Singapore. Electronic address: chmleehk@nus.edu.sg.
authors.forename: Hian Kee
authors.initials: HK
authors.lastname: Lee
mesh_terms: D000327:Adsorption; D002851:Chromatography, High Pressure Liquid; D004054:Diethylstilbestrol / Q000032:analysis; D004958:Estradiol / Q000032:analysis; D004967:Estrogens / Q000032:analysis; D004970:Estrone / Q000032:analysis; D004997:Ethinyl Estradiol / Q000032:analysis; D006108:Graphite; D057230:Limit of Detection; D052616:Solid Phase Extraction / Q000379:methods; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004967:Estrogens; D014874:Water Pollutants, Chemical; D014867:Water; D004970:Estrone; D004997:Ethinyl Estradiol; D004958:Estradiol; D004054:Diethylstilbestrol; D006108:Graphite
keywords: Estrogens; High performance liquid chromatography; Micro-solid phase extraction; Reduced graphene oxide; Sodium dodecyl sulfate