Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated ...Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt （Co） electrode, which is a layer of carbon conductive ink （C） physically doped with Co powder, and Ag/AgCI reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1：99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of lxl0-5 mol/L and a slope of over 30 mV/decade in acidic solution （pH 4.5） for HzPO4-. The proposed screen-printed sensor also ex- hibited significant reproducibility with a small repeated sensing deviation （i.e., relative standard deviation （R.S.D.） of 0.5%） on a single sensor and a small electrode-to-electrode deviation （i.e., R.S.D. 〈 3.2%）. The recovery study of HzPO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis.展开更多
基金supported by the Major Scientific Equipment Development Project of China(2012YQ030111)the Beijing Natural Science Foundation(8132032)
文摘Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt （Co） electrode, which is a layer of carbon conductive ink （C） physically doped with Co powder, and Ag/AgCI reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1：99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of lxl0-5 mol/L and a slope of over 30 mV/decade in acidic solution （pH 4.5） for HzPO4-. The proposed screen-printed sensor also ex- hibited significant reproducibility with a small repeated sensing deviation （i.e., relative standard deviation （R.S.D.） of 0.5%） on a single sensor and a small electrode-to-electrode deviation （i.e., R.S.D. 〈 3.2%）. The recovery study of HzPO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis.
