Nanovolume Gas-Free Hydroxide Eluent Generator for Open Tubular Ion Chromatography

Chouhan, Bikash; Shelor, C. Phillip; Huang, Weixiong; Chen, Yongjing; Dasgupta, Purnendu Κ.

doi:10.1021/acs.analchem.0c00505

Cited by 14 publications

(5 citation statements)

References 40 publications

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“…A principal goal behind making these polymers is to fabricate IEM-based microstructures for monolithic microsuppressors, eluent generators, etc., for open tubular ion chromatography (IC). While the polymer is cast around a 25 μm mandrel, after thermal annealing and conversion to the H + -form, the polymer expands.…”

Section: Resultsmentioning

confidence: 99%

Moldable Strong Cation Exchange Polymer and Microchannel Fabrication

Maleki

Dasgupta

2020

Anal. Chem.

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We characterize a high-capacity cation exchange membrane (CEM) synthesized from an aqueous poly(vinyl alcohol) (PVA) solution and varying amounts of a water-soluble ionic monomer, sodium styrenesulfonate. Highly hydrophilic but waterinsoluble transparent polymers with a range of ion exchange capacities (IECs) can be made; at the high end, the ion exchange capacities (IEC) is >2× that of the benchmark CEM, Nafion. The water uptake of the polymer (as moles of water/mole H + ) is 5−10× greater than that of Nafion. Except at the highest IECs (where steeply increasing water sorption and resultant swelling outpaces IEC increase), the specific conductance increases with increasing IEC while the conductance anisotropy decreases. The material withstands repeated regeneration cycles and hour-long boiling in water or alcohols. The aqueous prepolymer mixture can be cast around a fine wire acting as a mandrel. Fabrication of an ion exchanger microchannel, capable of withstanding at least 300 psi, is demonstrated. We also discuss entirely novel considerations on ab initio limits of conductance of ion exchange membranes.

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Section: Resultsmentioning

confidence: 99%

Moldable Strong Cation Exchange Polymer and Microchannel Fabrication

Maleki

Dasgupta

2020

Anal. Chem.

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“…These components have been demonstrated at a miniaturized scale. For example, Chouhan et al (2020) demonstrated a small hydroxide eluent generator suitable for flowrates in the nL regime and capable of gradient elution.…”

Section: Referencesmentioning

confidence: 99%

“…However, the loading capacity is very limited compared to packed columns due to the much lower surface area. For example, 4 nL of injection volume is slightly too large for 25 µm inner diameter capillary columns (Chouhan et al, 2020). Lower injection volumes are currently difficult to achieve with acceptable repeatability.…”

Section: Referencesmentioning

confidence: 99%

In situ organic biosignature detection techniques for space applications

Abrahamsson

Kanik

2022

Front. Astron. Space Sci.

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The search for life in Solar System bodies such as Mars and Ocean Worlds (e.g., Europa and Enceladus) is an ongoing and high-priority endeavor in space science, even ∼ five decades after the first life detection mission at Mars performed by the twin Viking landers. However, the in situ detection of biosignatures remains highly challenging, both scientifically and technically. New instruments are being developed for detecting extinct or extant life on Mars and Ocean Worlds due to new technology and fabrication techniques. These instruments are becoming increasingly capable of both detecting and identifying in situ organic biosignatures that are indicative of life and will play a pivotal role in the search for evidence of life through robotic lander missions. This review article gives an overview of techniques used for space missions (gas chromatography, mass spectrometry, and spectroscopy), the further ongoing developments of these techniques, and ion mobility spectrometry. In addition, current developments of techniques used in the next-generation instruments for organic biosignature detection are reviewed; these include capillary electrophoresis, liquid chromatography, biosensors (primarily immunoassays), and nanopore sensing; whereas microscopy, biological assays, and isotope analysis are beyond the scope of this paper and are not covered.

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“…Introduced in 1991, this principle has enjoyed considerable commercial success. A variety of electrodialytic generators in different scales and those capable of generating buffers with linear gradients in pH and ionic strength have since been described (see ref for a recent example and ref for a recent review). Also beginning in 1991, Olesik et al introduced enhanced fluidity liquid chromatography (EFLC) in which liquid CO 2 was mixed with polar organic mobile phases to address poor solvent polarity of CO 2 as used in supercritical fluid chromatography (SFC) .…”

Section: Introductionmentioning

confidence: 99%

Automated Programmable Generation of Broad pH Range Volatile Ionic Eluents for Liquid Chromatography

2021

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Many of the universal detectors in liquid chromatography, including mass spectrometry, must completely volatilize the chromatographic eluent first before further processing and detection of the analytes. A basic requirement is that the eluent does not contain a nonvolatile dissolved component. However, separation of biomolecules must be conducted in mostly aqueous media of compatible pH and ionic strength if their biological activity must survive the separation process. Combinations of ammonia with acetic and formic acids are commonly used as eluent for this purpose but generally maximum concentrations that can be tolerated are relatively low. Further, buffering is good only over a limited pH range. We describe a system where the eluent is generated in an automated pressureprogrammed manner from high-purity gaseous NH 3 and CO 2 through gas-permeable membrane devices. This can be aided by the prior presence of formic/acetic acids in the mobile phase to extend the attainable low pH limit. We outline the fundamental pH, ionic strength, and buffer intensity considerations and demonstrate the application of such eluents in the separation of amino acids, proteins, and monoclonal antibodies. We also demonstrate the use of dissolved CO 2 as an ion-pairing agent in the separation of chiral amines.

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Nanovolume Gas-Free Hydroxide Eluent Generator for Open Tubular Ion Chromatography

Cited by 14 publications

References 40 publications

Moldable Strong Cation Exchange Polymer and Microchannel Fabrication

Moldable Strong Cation Exchange Polymer and Microchannel Fabrication

In situ organic biosignature detection techniques for space applications

Automated Programmable Generation of Broad pH Range Volatile Ionic Eluents for Liquid Chromatography

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