A permeative amine/acid introduction device (PAID) is placed after a conventional KOH eluent suppressed conductometric anion chromatography (SCAC) system. The PAID converts the suppressed eluites from the acid form to the corresponding salt. For example, when the analytes are acids, they are converted to the corresponding ammonium salt (NR.sub.2H+HX.fwdarw.NR.sub.2H.sub.2.sup.++X.sup.−) and allows very weak acids HX (pK.sub.a≥7.0) that cannot normally be detected by SCAC to be measured by a second conductivity detector following the PAID. Permeative reagent introduction is dilutionless, can be operated without pumps and provides good mixing with low band dispersion (as small as 30 μL). An exemplary amine is diethylamine (DEA), which was chosen as the amine source due to its low pK.sub.b value (pK.sub.b 3.0), high vapor pressure, and low toxicity and low odor.

An ion suppressor includes ion exchange membranes between a pair of electrodes. Regeneration liquid channels are provided in the spaces between the electrodes and the ion exchange membranes, and an eluent channel is provided between the ion exchange membranes. Ion re-exchange in the eluent on the downstream side of the eluent channel is suppressed, thereby making it possible to improve the detection sensitivity for the ion to be measured. For example, the eluent channel has a folded structure, thereby increasing the amount of current on the downstream side of the eluent channel, and thus, the accumulation of ions is suppressed, and accordingly, ion re-exchange in the eluent can be suppressed.

An analytical system comprises a chromatography column configured to separate a sample into one or more analytes; an ion removal device configured to remove at least ions of one charge from the mobile phase, the ion removal device fluidly coupled to an output of the chromatography column; an ion selective sensor configured to measure a signal corresponding to an activity of the ions of one charge in the mobile phase, the ion selective sensor fluidly coupled to an output of the ion removal device; an optional diverter valve that can interrupt the flow of the mobile phase; and a microprocessor configured to monitor the signal of the ion selective sensor and to either switch the optional diverter valve to interrupt the flow of the mobile phase or turn off the pump when the signal is greater than a predetermined threshold.

An apparatus for suppressing an eluent of an aqueous sample stream including analyte ions of one charge, positive or negative, comprises a primary channel member, a first block, a first regenerant flow channel, a first charged barrier, a second block, a second regenerant flow channel, a second charged barrier, a first stationary flow-through ion exchange material, and optionally a first electrode and a second electrode. The first stationary flow-through ion exchange material comprises a polyolefin substrate having a functional polymer layer disposed thereon. The polyolefin substrate has a pore structure with a pore size ranging from about 5 microns to about 250 microns. The functional polymer layer has a thickness ranging from about 1 micron to about 20 microns, and a layer pore structure having a pore size ranging from about 1 nm to about 100 nm. The functional polymer layer comprises an ion exchange layer.

An ion chromatography (IC) suppressor includes a first clamping plate, an intermediate plate, a second clamping plate, a first ion exchange membrane, a second ion exchange membrane, a first electrode and a second electrode. The first clamping plate, the intermediate plate and the second clamping plate are tightly buckled in sequence to compact the first ion exchange membrane between the first clamping plate and the intermediate plate and compact the second ion exchange membrane between the intermediate plate and the second clamping plate. Resin particles are filled between the two ion exchange membranes. An eluent inlet and an eluent outlet are provided respectively at two ends of the intermediate plate, and an accommodating groove is formed at each of a tail end of the eluent inlet and a head end of the eluent outlet. The first clamping plate and the second clamping plate are provided with a sealing lip, respectively.

Systems and methods for inhibiting translocation of ions across ion exchange barriers include an eluent generator having an ion source reservoir with a first electrode, an eluent generation chamber with a second electrode, an ion exchange barrier disposed therebetween, and means for reversing the polarity of a voltage or current applied across the first and second electrodes. A first polarity voltage or current applied across the electrodes generates an electric field that promotes translocation of eluent counter ions from the reservoir across the barrier, where the counter ions combine with eluent ions electrolytically generated in the chamber. By reversing the polarity of the voltage or current across the electrodes, the resulting electric field inhibits translocation of counter ions across the barrier from the reservoir into the chamber. Reverse voltage or current bias reduces counter ion concentration in the resting chamber to prevent exhaustion of ion suppressor capacity during start up.

An ion chromatography (IC) suppressor includes a first clamping plate, an intermediate plate, a second clamping plate, a first ion exchange membrane, a second ion exchange membrane, a first electrode and a second electrode. The first clamping plate, the intermediate plate and the second clamping plate are tightly buckled in sequence to compact the first ion exchange membrane between the first clamping plate and the intermediate plate and compact the second ion exchange membrane between the intermediate plate and the second clamping plate. Resin particles are filled between the two ion exchange membranes. An eluent inlet and an eluent outlet are provided respectively at two ends of the intermediate plate, and an accommodating groove is formed at each of a tail end of the eluent inlet and a head end of the eluent outlet. The first clamping plate and the second clamping plate are provided with a sealing lip, respectively.

Open tubular capillary columns for liquid and ion chromatography, based upon an ionically impermeable polyolefin capillary having a bore with a sulfonate-group- or amine-group-functionalized internal surface. The capillary columns may include a coating of ion exchanging nanoparticles electrostatically bound to the functionalized internal surface. The capillary columns may be made by exposing the interior surface to a sulfonating reagent comprising chlorosulfonic acid (ClSO.sub.3H), preferably from 85 wt % to 95 wt % chlorosulfonic acid at a process temperature of 20 to 25° C. The interior surface may be subsequently exposed to an asymmetrical diamine to form a sulfonic mid-linkage to the diamine, i.e., to form a sulfonamide-linked, amine-group-functionalized internal surface. The coating may be provided by subsequently exposing the interior surface to an aqueous suspension of ion exchanging nanoparticles to electrostatically bond the ion exchanging nanoparticles to the functionalized internal surface.

A permeative amine/acid introduction device (PAID) is placed after a conventional KOH eluent suppressed conductometric anion chromatography (SCAC) system. The PAID converts the suppressed eluites from the acid form to the corresponding salt. For example, when the analytes are acids, they are converted to the corresponding ammonium salt (NR.sub.2H+HX.fwdarw.NR.sub.2H.sub.2.sup.++X.sup.−) and allows very weak acids HX (pK.sub.a≥7.0) that cannot normally be detected by SCAC to be measured by a second conductivity detector following the PAID. Permeative reagent introduction is dilutionless, can be operated without pumps and provides good mixing with low band dispersion (as small as 30 μL). An exemplary amine is diethylamine (DEA), which was chosen as the amine source due to its low pK.sub.b value (pK.sub.b 3.0), high vapor pressure, and low toxicity and low odor.

Systems and methods for inhibiting translocation of ions across ion exchange barriers include an eluent generator having an ion source reservoir with a first electrode, an eluent generation chamber with a second electrode, an ion exchange barrier disposed therebetween, and means for reversing the polarity of a voltage or current applied across the first and second electrodes. A first polarity voltage or current applied across the electrodes generates an electric field that promotes translocation of eluent counter ions from the reservoir across the barrier, where the counter ions combine with eluent ions electrolytically generated in the chamber. By reversing the polarity of the voltage or current across the electrodes, the resulting electric field inhibits translocation of counter ions across the barrier from the reservoir into the chamber. Reverse voltage or current bias reduces counter ion concentration in the resting chamber to prevent exhaustion of ion suppressor capacity during start up.