| abstract |
A flowing junction reference electrode exhibiting heretofore unattainable potentiometric characteristics is described, comprising a microfluidic liquid junction member that is situated between a reference electrolyte solution and a sample solution. This microfluidic liquid junction member has an array of nanochannels spanning the member and physically connecting the reference electrolyte solution and a sample solution, but while the electrolyte solution flows through the array of nanochannels and into the sample solution at a linear velocity, the sample solution does not substantially enter the array of nanochannels via the mechanisms of diffusion, migration, convection or other known mechanisms. The number of nanochannels in the array is preferably between approximately 10 8 and approximately 10. Also preferably, the nanochannels are substantially straight and are substantially parallel to one another; such an array of nanochannels is herein described as anisotropic. The nanochannels are also preferably coated. The widths of any nanochannels in the array of nanochannels are preferably uniform, in that the width of any nanochannel is substantially equal to the width of any other nanochannels in the array. The nanochannels preferably have widths of greater than approximately 1 nanometer and less than approximately 500 nanometers, and most preferably of 70 nanometers. The electrode may be constructed out of any suitable material, and is preferably is constructed of a polymer, most preferably a polymer selected from the group consisting of polycarbonate and polyimide, and may also preferably be constructed of silicon, glass, or ceramic. |