| 摘要 |
1,125,358. Electro-chemical analysis. V. PRETORIUS and H.H. HAHN. July 26, 1967 [Aug. 2, 1966], No.34443/67. Addition to 1,120.364. Heading G1N. The progress of a chromatogram in a liquid chromatography system is monitored by passing a moving liquid phase of the system in contact with a solid detection electrode and observing a constitution and concentration dependent electrical quantity detectable at the detection electrode with reference to a reference electrode connected to the system. The electrical quantity may be changes in the electrical double layer on the detection electrode produced by the zeta effect, or the capacitance between the electrodes, or the conductivity of the eluate. A solute may be detected indirectly by observing the rate of an electrolytic reaction involving oxygen dissolved in the forwarding phase. For measuring conductivity at the outlet of a chromatographic column, the column wall (2), made of stainless steel, may serve as one electrode, and a smaller diameter glassy carbon tube (4) as the other. For measuring conductivity at a point intermediate the ends of a column, two porous layers (9), (10) of sintered resin powder containing metal or graphite separated by an insulating layer of sintered P.T.F.E. (13) may be used. Alternatively, two graphite rods may extend in diametrically opposing relationship through the walls of a glass column. For measuring zeta effect, two glassy carbon ring electrodes (15), (16) separated by a capillary tube (14) may be used. One of the ring electrodes may co-operate with the stainless steel tube (2) for measuring conductivity. Several detectors, selectable by switches, may be situated at different stages of a chromatographic system. Examples of substances which may be detected include: fatty acids, aromatic nitro compounds, and pesticides. |
