Magnetophoretic velocimetry of manganese(II) in a single microdroplet in a flow system under a high gradient magnetic field generated with a superconducting magnet
Magnetophoretic velocimetry of manganese(II) in a single microdroplet in a flow system under a high gradient magnetic field generated with a superconducting magnet
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DOI：
10.1021/ac0203037
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发表时间：
2002-10-01
影响因子：
7.4
通讯作者：
Watarai, H
中科院分区：
文献类型：
--
作者：
Suwa, M;Watarai, H
研制了一套磁泳测速实验系统，该系统可由磁泳速度测定分散在液相中的单个颗粒的体积磁磁化率。超导磁体（10 T）中的一对铁极片可以在毛细管中产生微米级的高梯度磁场。研究了非均匀磁场作用下毛细管流动体系中单个颗粒的磁泳行为。从分散在MnCl 2水溶液中的聚苯乙烯胶乳颗粒的磁泳速度，确定磁通量密度和梯度的乘积B（dB/dx）作为沿毛细管沿着的位置的函数。B（dB/dx）的最大值为4.7 × 10（4）T-2 m（-1），比两块Nd-Fe-B永磁体（0.4 T）的最大值提高了近100倍。用2-噻吩甲酰三氟丙酮和三正辛基氧化膦从MnCl 2溶液中萃取锰（II）的有机液滴被用作测试样品。液滴与介质的体积磁化率之差可以由磁泳速度来确定。该方法使我们能够连续测量皮升液滴的10（-6）水平的体积磁化率，并在阿托摩尔水平上测定单个液滴中的锰（II）。
An experimental system for magnetophoretic velocimetry, which could determine the volume magnetic susceptibitity of a single particle dispersed in a liquid phase from a magnetophoretic velocity, has been developed. A micrometer-sized high-gradient magnetic field could be generated in a capillary by a pair of iron pole pieces in a superconducting magnet (10 T). The magnetophoretic behavior of a single particle in a capillary flow system was investigated under the inhomogeneous magnetic field. From the magnetophoretic velocity of a polystyrene latex particle dispersed in a MnCl2 aqueous solution, the product of the magnetic flux density and the gradient, B(dB/dx), was determined as a function of the position along the capillary. The maximum value of B(dB/dx) was 4.7x10(4) T-2 m(-1), which was similar to100 times higher than that obtained by two Nd-Fe-B permanent magnets (0.4 T). Organic droplets extracting manganese(II) with 2-thenoyltrifluoroacetone and tri-n-octytphosphine oxide from MnCl2 solution were used as test samples. The difference of the volume magnetic susceptibility between the droplet and the medium could be determined from the magnetophoretic velocity. This method allowed us to continuously measure a volume magnetic susceptibility of 10(-6) level for a picoliter droplet and to determine manganese(II) in the single droplet at the attomole level.