| 摘要 |
An apparatus for generating high purity acid or base in an aqueous stream for use as an eluent for chromatography and, particularly, ion chromatography. For generating a base for anion chromatography, the aqueous stream is directed through a cation exchange bed. An electrical potential is applied to the bed. Cations on the bed electromigrate into the aqueous stream while hydroxide ions are electrolytically generated to form a base-containing eluent. Anions to be detected and the generated eluent flow through a chromatographic separator and a detector. In one embodiment, between separation and detection, the separated anion stream flows through a second cation exchange bed with no electrical potential applied. The second bed serves as a suppressor. After completion of the desired number of cycles, flow through the first and second cation exchange beds may be reversed by appropriate valving for the next sample stream. An electrical potential is applied to the second bed while the potential is discontinued in the first bed. Thus, the second bed generates eluent and the first bed suppresses conductivity of the base. In another embodiment, the second cation exchange bed is disposed after the detector as a sink to retain the cations of the base and the eluent. By appropriate valving, flow may be reversed through the first and second beds with potential applied in the second bed but not the first bed. During the reversal setting of the valving, the second bed generates the base. |
