초록 ▼

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

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.

대표청구항 ▼

[ What is claimed is:] [1.] Apparatus for generating an eluent and using the same in anion analysis comprising(a) a flowthrough first cation exchange bed including exchangeable cations, said first cation exchange bed comprising an upstream bed portion comprising a strongly acidic cation exchange mat

[ What is claimed is:] [1.] Apparatus for generating an eluent and using the same in anion analysis comprising(a) a flowthrough first cation exchange bed including exchangeable cations, said first cation exchange bed comprising an upstream bed portion comprising a strongly acidic cation exchange material and an adjacent downstream bed portion comprising a weakly acidic cation exchange material,(b) a first electrode in electrical communication with the inlet portion of said first cation exchange bed and a second electrode in electrical communication with the outlet portion thereof,(c) a power supply for applying an electrical potential between said first and second electrodes while an aqueous stream is flowing in a first direction therethrough for electrolytically generating hydroxide ions and displacing exchangeable cations into said aqueous stream to form a first eluent comprising a base,(d) a sample injection port for injecting a liquid sample stream containing anions to be detected,(e) a chromatographic separator having an inlet and an outlet, said inlet being in flulid communication with said sample injection port and said first eluent for separating anions to be detected in a first sample stream flowing through said port and forming a first chromatography effluent exiting from said chromatographic separator, and(f) a detector in fluid communication with the outlet of said first chromatographic separator for detecting the separated anions in said first chromatographic effluent.