title: Trace-level mercury ion (Hg2+) analysis in aqueous sample based on solid-phase extraction followed by microfluidic immunoassay.
abstract: Mercury is considered the most important heavy-metal pollutant, because of the likelihood of bioaccumulation and toxicity. Monitoring widespread ionic mercury (Hg(2+)) contamination requires high-throughput and cost-effective methods to screen large numbers of environmental samples. In this study, we developed a simple and sensitive analysis for Hg(2+) in environmental aqueous samples by combining a microfluidic immunoassay and solid-phase extraction (SPE). Using a microfluidic platform, an ultrasensitive Hg(2+) immunoassay, which yields results within only 10 min and with a lower detection limit (LOD) of 0.13 μg/L, was developed. To allow application of the developed immunoassay to actual environmental aqueous samples, we developed an ion-exchange resin (IER)-based SPE for selective Hg(2+) extraction from an ion mixture. When using optimized SPE conditions, followed by the microfluidic immunoassay, the LOD of the assay was 0.83 μg/L, which satisfied the guideline values for drinking water suggested by the United States Environmental Protection Agency (USEPA) (2 μg/L; total mercury), and the World Health Organisation (WHO) (6 μg/L; inorganic mercury). Actual water samples, including tap water, mineral water, and river water, which had been spiked with trace levels of Hg(2+), were well-analyzed by SPE, followed by microfluidic Hg(2+) immunoassay, and the results agreed with those obtained from reduction vaporizing-atomic adsorption spectroscopy.
authors.affiliation: Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Abiko City, Chiba, Japan. date-ya@criepi.denken.or.jp
authors.forename: Yasumoto
authors.initials: Y
authors.lastname: Date
authors.forename: Arata
authors.initials: A
authors.lastname: Aota
authors.forename: Shingo
authors.initials: S
authors.lastname: Terakado
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sasaki
authors.forename: Norio
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Matsue
authors.forename: Naoya
authors.initials: N
authors.lastname: Ohmura
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D060766:Drinking Water / Q000032:analysis; D005618:Fresh Water / Q000032:analysis; D007118:Immunoassay; D007474:Ion Exchange; D007477:Ions / Q000737:chemistry; D008628:Mercury / Q000032:analysis* / Q000302:isolation & purification; D046210:Microfluidic Analytical Techniques; D045483:Rivers / Q000737:chemistry; D052616:Solid Phase Extraction; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D000911:Antibodies, Monoclonal; D060766:Drinking Water; D007477:Ions; D014874:Water Pollutants, Chemical; D008628:Mercury