Shingo Terakado
Central Research Institute of Electric Power Industry
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Featured researches published by Shingo Terakado.
Analytical Chemistry | 2013
Yasumoto Date; Arata Aota; Shingo Terakado; Kazuhiro Sasaki; Norio Matsumoto; Yoshitomo Watanabe; Tomokazu Matsue; Naoya Ohmura
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.
Biosensors and Bioelectronics | 2012
Yasumoto Date; Shingo Terakado; Kazuhiro Sasaki; Arata Aota; Norio Matsumoto; Hitoshi Shiku; Kosuke Ino; Yoshitomo Watanabe; Tomokazu Matsue; Naoya Ohmura
A simple and rapid flow-based multioperation immunoassay for heavy metals using a microfluidic device was developed. The antigen-immobilized microparticles in a sub-channel were introduced as the solid phase into a main channel structures through a channel flow mechanism and packed into a detection area enclosed by dam-like structures in the microfluidic device. A mixture of a heavy metal and a gold nanoparticle-labeled antibody was made to flow toward the corresponding metal through the main channel and make brief contact with the solid phase. A small portion of the free antibody was captured and accumulated on the packed solid phase. The measured absorbance of the gold label was proportional to the free antibody portion and, thus, to the metal concentration. Each of the monoclonal antibodies specific for cadmium-EDTA, chromium-EDTA, or lead-DTPA was applied to the single-channel microfluidic device. Under optimized conditions of flow rate, volume, and antibody concentration, the theoretical (antibody K(d)-limited) detection levels of the three heavy metal species were achieved within only 7 min. The dynamic range for cadmium, chromium, and lead was 0.57-60.06 ppb, 0.03-0.97 ppb, and 0.04-5.28 ppb, respectively. An integrated microchannel device for simultaneous multiflow was also successfully developed and evaluated. The multiplex cadmium immunoassay of four samples was completed within 8 min for a dynamic range of 0.42-37.48 ppb. Present microfluidic heavy metal immunoassays satisfied the Japanese environmental standard for cadmium, chromium and, lead, which provided in the soil contamination countermeasures act.
Analytical Chemistry | 2011
Arata Aota; Yasumoto Date; Shingo Terakado; Hideo Sugiyama; Naoya Ohmura
Polychlorinated biphenyls (PCBs) that are present in transformer oil are a common global problem because of their toxicity and environmental persistence. The development of a rapid, low-cost method for measurement of PCBs in oil has been a matter of priority because of the large number of PCB-contaminated transformers still in service. Although one of the rapid, low-cost methods involves an immunoassay, which uses multilayer column separation, hexane evaporation, dimethyl sulfoxide (DMSO) partitioning, antigen-antibody reaction, and a measurement system, there is a demand for more cost-effective and simpler procedures. In this paper, we report a DMSO partitioning method that utilizes a microfluidic device with microrecesses along the microchannel. In this method, PCBs are extracted and enriched into the DMSO confined in the microrecesses under the oil flow condition. The enrichment factor was estimated to be 2.69, which agreed well with the anticipated value. The half-maximal inhibitory concentration of PCBs in oil was found to be 0.38 mg/kg, which satisfies the much stricter criterion of 0.5 mg/kg in Japan. The developed method can realize the pretreatment of oil without the use of centrifugation for phase separation. Furthermore, the amount of expensive reagents required can be reduced considerably. Therefore, our method can serve as a powerful tool for achieving a simpler, low-cost procedure and an on-site analysis system.
Bunseki Kagaku | 2006
Naoya Ohmura; Thomas R. Glass; Kazuhiro Sasaki; Takashi Joh; Yukihiro Taemi; Naoyuki Yokobori; Shingo Terakado
Analytical Sciences | 2014
Shingo Terakado; Thomas R. Glass; Kazuhiro Sasaki; Naoya Ohmura
Analytical Sciences | 2013
Arata Aota; Yasumoto Date; Shingo Terakado; Naoya Ohmura
Analytical Sciences | 2013
Shingo Terakado; Naoya Ohmura; Seok-Un Park; Seung-Min Lee; Thomas R. Glass
Bunseki Kagaku | 2006
Naoya Ohmura; Thomas R. Glass; Kazuhiro Sasaki; Takashi Joh; Yukihiro Taemi; Katsuya Imanishi; Shingo Terakado
Analytical Chemistry Research | 2015
Arata Aota; Yasumoto Date; Shingo Terakado; Naoya Ohmura
Bunseki Kagaku | 2012
Shingo Terakado; Thomas R. Glass; Yoshihiro Saito; Yasumoto Date; Naoya Ohmura