Ion chromatography systems with flow-delay eluent recycle

A chromatographic method comprising:

• (a) injecting sample ionic species into an aqueous eluent stream from an eluent source,
• (b) chromatographically separating sample ionic species in an aqueous liquid eluent stream flowing through a chromatography separation medium, to form a chromatography effluent,
• (c) suppressing the chromatography effluent from step (b) by flowing it through a chromatography effluent flow channel in an electrolytic membrane suppressor to exit as a suppressor effluent stream,
• (d) flowing said suppressor effluent stream past a flow-through detector to exit as a detector effluent stream,
• (e) flowing the detector effluent stream from step (d) through a first detector effluent flow channel in said membrane suppressor on the opposite side of a first ion exchange membrane from said chromatography effluent flow channel, said detector effluent exiting said first detector effluent flow channel as a recycle stream,
• (f) flowing said recycle stream through a catalytic gas elimination chamber to catalytically combine hydrogen and oxygen gas, or catalytically decomposing hydrogen peroxide, or both, to form water thereby reducing the gas content in said recycle stream, and
• (g) flowing said recycle stream from said catalytic gas elimination chamber to said chromatography separation medium, the time for flow of said detector effluent from said first detector effluent flow channel to said catalytic gas elimination chamber being at least 0.5 minute to facilitate decomposition of unstable oxidation compounds.

A chromatographic method comprising:

• (a) injecting sample ionic species into an aqueous eluent stream from an eluent source,
• (b) chromatographically separating sample ionic species in an aqueous liquid eluent stream flowing through a chromatography separation medium, to form a chromatography effluent,
• (c) suppressing the chromatography effluent from step (b) by flowing it through a chromatography effluent flow channel in an electrolytic membrane suppressor to exit as a suppressor effluent stream,
• (d) flowing said suppressor effluent stream past a flow-through detector to exit as a detector effluent stream,
• (e) flowing the detector effluent stream from step (d) through a first detector effluent flow channel in said membrane suppressor on the opposite side of a first ion exchange membrane from said chromatography effluent flow channel, and then through a second detector effluent flow channel on the opposite side of a second ion exchange membrane in said membrane suppressor from said chromatographic effluent flow channel, said detector effluent exiting said second detector effluent flow channel as a recycle stream,
• (f) flowing said recycle stream through a catalytic gas elimination chamber to catalytically combine hydrogen and oxygen gas, or catalytically decomposing hydrogen peroxide, or both, to form water thereby reducing the gas content in said recycle stream, and
• (g) flowing said recycle stream from said catalytic gas elimination chamber to said chromatography separation medium.

A chromatographic method comprising the steps of:

• (a) injecting sample ionic species into an aqueous eluent stream,
• (b) chromatographically separating said sample ionic species in said eluent stream by flowing the same through chromatographic separation medium,
• (c) detecting said separated sample ionic species in said eluent stream effluent from said chromatographic medium,
• (d) catalytically combining hydrogen and oxygen gases or catalytically decomposing hydrogen peroxide, or both, in said eluent stream in a catalytic gas elimination chamber, to form water and reduce the gas content in an eluent stream, in an effluent stream flowing from said catalytic gas elimination chamber, and
• (e) detecting bubbles in said catalytic gas elimination chamber effluent stream.

A chromatographic method comprising the steps of:

• (a) injecting sample ionic species into an aqueous eluent stream,
• (b) chromatographically separating said sample ionic species in said eluent stream by flowing the same through chromatographic separation medium,
• (c) detecting said separated sample ionic species in said eluent stream effluent from said chromatographic medium,
• (d) catalytically combining hydrogen and oxygen gases or catalytically decomposing hydrogen peroxide, or both, in said eluent stream in a catalytic gas elimination chamber, to form water and reduce the gas content in an eluent stream, effluent exiting from said catalytic gas elimination chamber, and
• (e) between steps (c) and (d), applying energy to said gas elimination effluent to decompose at least a portion of any unstable oxidative compounds therein.

A chromatographic method comprising the steps of:

• (a) injecting sample ionic species into an aqueous stream,
• (b) chromatographically separating said sample ionic species in said aqueous stream by flowing the same through chromatographic separation medium while applying an electric field across said separation medium, to exit as a chromatography effluent,
• (c) flowing said chromatography effluent through a detector to detect said separated sample ionic species in said chromatography effluent to exit as a detector effluent stream,
• (d) catalytically combining hydrogen and oxygen gases or catalytically decomposing hydrogen peroxide, or both, in said detector effluent stream by flowing it through a catalytic gas elimination chamber, to form water and reduce the gas content of the eluent effluent stream exiting said gas elimination chamber, and
• (e) recycling said catalytic gas elimination chamber effluent stream from said catalytic gas elimination chamber to said chromatography separation column.

A chromatography apparatus comprising:

• (a) a chromatography column including chromatographic separation medium disposed in the column lumen,
• (b) spaced electrodes in electrical communication with said separation medium and disposed to pass an electric current through said separation medium,
• (c) a detector,
• (d) a conduit for an aqueous liquid stream providing fluid communication between said detector and said chromatographic separation medium, and
• (e) a catalytic gas elimination chamber in fluid communication with said conduit and including a catalyst for combining hydrogen and oxygen gases, or for catalytically decomposing hydrogen peroxide, or both, in said eluent stream to form water and reduce the gas content in said eluent stream.