Magnetophoretic Velocimetry of Manganese(II) in a Single Emulsion Droplet at the Femtomole Level

详细信息    查看全文

• 作者：Masayori Suwa and Hitoshi Watarai
• 刊名：Analytical Chemistry
• 出版年：2001
• 出版时间：November 1, 2001
• 年：2001
• 卷：73
• 期：21
• 页码：5214 - 5219
• 全文大小：119K
• 年卷期：v.73,no.21(November 1, 2001)
• ISSN：1520-6882

文摘

We developed a new experimental technique namedmagnetophoretic velocimetry to determine a small amountof paramagnetic species in a single microdroplet. Themagnetophoretic velocity of an aqueous droplet containingparamagnetic metal ion dispersed in an organic mediumcould response to a very small amount of the metal ionunder an inhomogeneous magnetic field. The paramagnetic droplet (2~8 m diam) used as a test sample in thisstudy was the aqueous droplet of manganese(II) chloridedispersed in ethylbenzoate whose density was nearly equalto water. A pair of small Nd-Fe-B magnets placed witha gap of 400 m generated an inhomogeneous magneticfield between the edges, at which the product of themagnetic flux density and the gradient, B(B/x), was ashigh as 410 T² m^-1. When a silica capillary containingthe emulsion was inserted into the gap between themagnets, the magnetophoretic migration of the dropletswas observed with a video microscope. The magnetophoretic velocity divided by the squared radius of thedroplet was proportional to the MnCl₂ concentration inthe droplet, as predicted by a theoretical calculation. Theestimated detection limit in this simple method was lowerthan 10^-16 mol for manganese(II).