16:00 〜 18:00
▲ [6p-PB6-11] Effect of introduced bubbles to the generation of liquid electrode plasma by alternating current power source
キーワード：liquid electrode plasma
Liquid electrode plasma (LEP) is an alternative excitation source for elemental analysis. LEP forms in a vapor bubble generated inside a narrow-center microchannel by using high-voltage power. More recently, we found the better conditions to generate LEP by alternating current with higher stability and significantly low damages on microchannel, called the new method as AC-LEP[1]. In this plasma, an air bubble remained in the LEP channel during plasma generation by AC power source. The bubble is expected to affect plasma generation strongly. In order to investigate in detail the effect of the bubbles, we fabricated a microfluidic system to introduce different kinds of gas bubbles intentionally into the LEP channel.
The channel was prior carved on the PDMS sheet by conventional photolithographic technique using SU-8 mold. In Fig. 1, there are three inlets, two liquid inlets and a gas inlet, and one outlet on the chip were punched with two 2-mm diameter holes. After that, the PDMS layer and the substrate were bound together by oxygen plasma. A syringe pump, as shown in Fig. 2 dispensed the liquid that is 0.1 M HNO3 and many kinds of gases, Argon, Nitrogen, Oxygen and air. Then AC-LEP was generated with specially power-controlled AC-power source (Plasma Concept Tokyo). The plasma was observed with a microscope, a high-speed camera, and a UV-VIS Spectrometer.
Figure 3 shows the spectrum of blank solution (0.1 M HNO3) and analyte solution (5 ppm Pb in 0.1M HNO3) in AC-LEP with the introduction of the various gases. The intensity differences of signal were observed at the wavelength of 261 nm for Pb. The differences increase in the case of introduction of N2, O2, and Air compared to the case without gas introduction.
Reference: [1] D. V. Khoai, H. Miyahara, T. Yamamoto, P. T. Tue, A. Okino, and Y. Takamura. Jpn. J. Appl. Phys. 55, 02BC23 (2016)
The channel was prior carved on the PDMS sheet by conventional photolithographic technique using SU-8 mold. In Fig. 1, there are three inlets, two liquid inlets and a gas inlet, and one outlet on the chip were punched with two 2-mm diameter holes. After that, the PDMS layer and the substrate were bound together by oxygen plasma. A syringe pump, as shown in Fig. 2 dispensed the liquid that is 0.1 M HNO3 and many kinds of gases, Argon, Nitrogen, Oxygen and air. Then AC-LEP was generated with specially power-controlled AC-power source (Plasma Concept Tokyo). The plasma was observed with a microscope, a high-speed camera, and a UV-VIS Spectrometer.
Figure 3 shows the spectrum of blank solution (0.1 M HNO3) and analyte solution (5 ppm Pb in 0.1M HNO3) in AC-LEP with the introduction of the various gases. The intensity differences of signal were observed at the wavelength of 261 nm for Pb. The differences increase in the case of introduction of N2, O2, and Air compared to the case without gas introduction.
Reference: [1] D. V. Khoai, H. Miyahara, T. Yamamoto, P. T. Tue, A. Okino, and Y. Takamura. Jpn. J. Appl. Phys. 55, 02BC23 (2016)