Application of ion chromatography in clinical studies and pharmaceutical industry.

Ion chromatography is a well-established regulatory method for analyzing anions and cations in environmental, food and many other samples. It offers an enormous range of possibilities for selecting stationary and mobile phases. Additionally, it usually helps to solve various separation problems, particularly when it is combined with different detection techniques. Ion chromatography can also be used to determine many ions and substances in clinical and pharmaceutical samples. It provides: availability of high capacity stationary phases and sensitive detectors; simple sample preparation; avoidance of hazardous chemicals; decreased sample volumes; flexible reaction options on a changing sample matrix to be analyzed; or the option to operate a fully-automated system. This paper provides a short review of the ion chromatography applications for determining different inorganic and organic substances in clinical and pharmaceutical samples.

Preparation and quality assessment of high-purity ginseng total saponins by ion exchange resin combined with macroporous adsorption resin separation.

AIM: To prepare high-purity ginseng total saponins from a water decoction of Chinese ginseng root. METHOD: Total saponins were efficiently purified by dynamic anion-cation exchange following the removal of hydrophilic impurities by macroporous resin D101. For quality control, ultrahigh-performance liquid chromatography with a charged aerosol detector (CAD) was applied to quantify marker components. The total saponin content was estimated by a colorimetric method using a vanillin-vitriol system and CAD response. RESULTS: D201, which consisted of a cross-linked polystyrene matrix and -N(+)(CH3)3 functional groups, was the best of the four anion exchange resins tested. However, no significant difference in cation exchange ability was observed between D001 (strong acid) and D113 (weak acid), although they have different functional groups and matrices. After purification in combination with D101, D201, and D113, the estimated contents of total saponins were 107% and 90% according to the colorimetric method and CAD response, respectively. The total amount of representative ginsenosides Re, Rd, Rg1, and compound K was approximately 22% based on ultrahigh-performance liquid chromatography-CAD quantitative analysis. CONCLUSION: These findings suggest that an ion exchange resin, combined with macroporous adsorption resin separation, is a promising and feasible purification procedure for neutral natural polar components.

A simple method using on-line continuous leaching and ion exchange chromatography coupled to inductively coupled plasma mass spectrometry for the speciation analysis of bio-accessible arsenic in rice.

A simple method for the speciation analysis of bio-accessible arsenic (As) in rice was developed using a continuous on-line leaching method to release the bio-accessible fraction. The continuous on-line leaching method has several advantages over commonly used batch methods including quicker and easier sample preparation, reduced risk of contamination and access to real time leaching data. The bio-accessibility of As in the samples was monitored using inductively coupled plasma mass spectrometry (ICP-MS). Results from a certified reference material as well as cooked and uncooked white rice showed that the majority of As was leached by saliva. Results obtained using the continuous on-line leaching method were comparable to those obtained using a batch method. Speciation analysis of the saliva leachate was performed using ion exchange chromatography coupled to ICP-MS. The four most toxic forms of As (As(III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and As(V)) were clearly separated within 5 min in a single chromatographic run. Over 92% of bio-accessible As in the certified reference material and uncooked white rice sample was in the form of DMA and As(V), whereas it was present as DMA and As(III) in the cooked white rice.

Portable, lightweight, low power, ion chromatographic system with open tubular capillary columns.

Basic operation principles of a lightweight, low power, low cost, portable ion chromatograph utilizing open tubular ion chromatography in capillary columns coated with multi-layer polymeric stationary phases are demonstrated. A minimalistic configuration of a portable IC instrument was developed that does not require any chromatographic eluent delivery system, nor sample injection device as it uses gravity-based eluent flow and hydrodynamic sample injection adopted from capillary electrophoresis. As a detection device, an inexpensive commercially available capacitance sensor is used that has been shown to be a suitable substitute for contactless conductivity detection in capillary separation systems. The built-in temperature sensor allows for baseline drift correction typically encountered in conductivity/capacitance measurements without thermostating device. The whole instrument does not require any power supply for its operation, except the detection and data acquisition part that is provided by a USB port of a Netbook computer. It is extremely lightweight, its total weight including the Netbook computer is less than 2.5kg and it can be continuously operated for more than 8h. Several parameters of the instrument, such as detection cell design, eluent delivery systems and data treatment were optimized as well as the composition of eluent for non-suppressed ion chromatographic analysis of common inorganic cations (Na(+), NH(4)(+), K(+), Cs(+), Ca(2+), Mg(2+), transition metals). Low conductivity eluents based on weakly complexing organic acids such as tartaric, oxalic or pyridine-2,6-dicarboxylic acids were used with contactless capacitance detection for simultaneous separation of mono- and divalent cations. Separation of Na(+) and NH(4)(+) cations was optimized by addition of 18-crown-6 to the eluent. The best separation of 6 metal cations commonly present in various environmental samples was accomplished in less than 30min using a 1.75mM pyridine-2,6-dicarboxylic acid and 3mM 18-crown-6 eluent with excellent repeatability (below 2%) and detection limits in the low micromolar range. The analysis of field samples is demonstrated; the concentrations of common inorganic cations in river water, mineral water and snow samples were determined.

Comparative study of strong anion exchangers: structure-related chromatographic performances.

Chromatographic performances are highly influenced by operational parameters. New ion exchangers have tailored matrices providing low backpressure and allowing high flow velocity. By systematic frontal analysis and selectivity determination at different flow rates, we suggested an independent evaluation of major anion exchangers to facilitate media selection, and investigated the relationship between (i) surface modification and (ii) chromatographic performances. Structure-extended resins showed higher binding capacities compared to resins with conventional ligands directly attached to the matrix. Moreover, they maintained mainly high capacities even with extremely high flow velocities. Ligand accessibility was therefore largely enhanced, allowing proteins to interact and bind under harsh conditions. High throughput resins can be used for purification of high volume and high concentration feedstock in limited time. This results in higher productivity and could contribute to cost reduction.

Ion chromatography-atmospheric pressure chemical ionization mass spectrometry for the determination of trace chlorophenols in clam tissues.

A novel analytical method has been developed for the determination of 14 trace chlorophenols in clam tissues by ion chromatography (IC) coupled with atmospheric pressure chemical ionization mass spectrometry (APCI-MS) in the negative mode. The method comprised a fast ultrasound-assisted extraction using a mixture of methanol/water (4:1v/v) containing 5% triethylamine (TEA) as extraction solvent, solid-phase extraction with an Oasis HLB cartridge and gradient separation using KOH/acetonitrile at a flow rate of 1.0 mL/min on an IonPac AG11 guard column (50 mm x 4.0 mm I.D.) and an IonPac AS11 analytical column (250 mm x 4.0 mm I.D.). The molecular ions m/z [M-H](-) 127, 129; 161, 163; 195, 197 and 263, 265, 267 were selected for quantification in the selected ion monitoring (SIM) mode for monochlorophenols (MCPs), dichlorophenols (DCPs), trichlorophenols (TCPs) and pentachlorophenol (PCP), respectively. The average recoveries of the objective compounds spiked in clam tissues were between 80.2% and 98.2%. Within-day and day-to-day relative standard deviations were less than 12.6% and 13.2%, respectively. The optimum IC-APCI-MS conditions were successfully applied to the analyses of 14 trace chlorophenols in clam tissues.

The purification of human urinary kallikrein with ion-exchange radial flow membrane chromatography.

A method was developed for the purification of kallikrein from human urine. The procedure consisted of three steps: ultradialysis, diethyl-(2-hydroxypropyl) aminoethyl (QAE) ion exchange radial flow membrane chromatography and affinity chromatography on aprotinin agarose. It is simple and suitable for large-scale purification. The purified product was checked by SDS-PAGE and matrix-assisted laser desorption:ionization mass spectrometery (MALDI). A single band with apparent molecular weight (MW) 42,000 in SDS-PAGE and a single monomer peak with MW33,000 in MALDI were observed, respectively. The biological activity tested by ELISA showed positive immunological identity of the purified product compared with human urinary kallikrein standard.

A simple and inexpensive chromatographic method for the purification of gamma-globulin from human serum.

Inexpensive cation- and anion-exchangers based on continuous polymer beds were prepared directly in a plastic syringe. These beds are unique in the sense that they are synthesized by a very simple and cost-effective procedure; for instance, no preparation of beads is required as in conventional methods. Highly purified gamma-globulin could be prepared easily by step-wise elution accomplished by forcing buffers of increasing salt concentration through the column with the aid of the plunger.