Use of Triethylamine as an Ion-Pairing Reagent

Chuang, Cherng-Zee; Ragan, Francis Avery; Prasad, Chandan

doi:10.1080/10826079408013487

Cited by 11 publications

(5 citation statements)

References 15 publications

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“…Specifically, we used triethylamine (TEA) (HPLC grade, Fluka) (16.3 mM, final concentration) as the ion-pair agent. TEA is shown to have a fast equilibration time with the column [35]. Furthermor 400 mM 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) (99+%, Sigma) and methanol (see concentration below), the two organic modifiers, were included [33].…”

Section: Methodsmentioning

confidence: 99%

Single-nucleotide resolution of RNAs up to 59 nucleotides by high-performance liquid chromatography

Huang

Jayaseelan

Hebert

et al. 2013

Analytical Biochemistry

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Ion-pair, reverse-phase high performance liquid chromatography (HPLC) is a standard analytical platform for separating, purifying and analyzing RNAs. However, a single-nucleotide resolution by using HPLC is currently limited to RNAs shorter than 25 nucleotides (nt). Here we describe a method of separating three RNA aptamers with 57, 58 and 59 nt on an XBridge ion-pair, reverse-phase HPLC column by a single-nucleotide resolution. Under a similar condition, we also show the capability of our method to resolve two structurally different, yet sequence or mass identical 59-nt aptamers. We establish that the optimal condition to achieve a single-nucleotide resolution correlates to 50 °C and zero magnesium concentration in mobile phases. The ion-pairing agent, the buffer and the solvent we use are also compatible for post-HPLC analysis such as mass spectrometry. Therefore, our method provides a new way of detecting, analyzing and separating RNAs by conformation or structure, and extends the ability of separating RNAs that are longer than 25-nt in length by single-nucleotide resolution.

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Section: Methodsmentioning

confidence: 99%

Single-nucleotide resolution of RNAs up to 59 nucleotides by high-performance liquid chromatography

Huang

Jayaseelan

Hebert

et al. 2013

Analytical Biochemistry

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“…The consumption of chemical reagents (triethylamine) and organic solvents (acetonitrile) in the preparation of the mobile phase was eliminated or reduced as compared with other methods (75% acetonitrile) [6]. Triethylamine affects the interaction with the column and improves the peak shape [35,36], but it shortens the life of the column. Organic solvents affect the health of the analysts and the environment.…”

Section: Introductionmentioning

confidence: 99%

Validation of an RP-HPLC Method for the Determination of Asenapine Maleate in Dissolution Media and Application to Study In Vitro Release from Co-Crystals

Al-Nimry

Khanfar

2021

Sci. Pharm.

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Asenapine maleate is an antipsychotic drug that is indicated in the treatment of schizophrenia and bipolar disorders. It has low aqueous solubility and high permeability (Class II drug) and undergoes an extensive first pass effect. These problems result in low oral bioavailability (<2%). To enhance its solubility/dissolution rate and hence bioavailability, co-crystals using different co-formers in different ratios were prepared and evaluated. To study the in vitro dissolution of the drug from these co-crystals into phosphate buffer (pH 6.8), an RP-HPLC method was developed and validated according to the ICH Q2R1 guidelines. The method was linear in the range 0.1-14 µg/ml (R >0.9998) and accurate and precise. An ANOVA test indicated that calibration curves run on different days did not differ significantly. It was sensitive (lower limit of quantitation (LLOQ) =25.03 ng/ml), specific (the co-formers did not interfere with the determination of the drug), and robust to small changes in the mobile phase (pH, composition, and flow rate). The in vitro release of asenapine maleate from the co-crystals and the physical mixture was much enhanced when compared to the in vitro dissolution of the unprocessed drug. In conclusion, the developed and validated RP-HPLC method met the acceptance criteria and was applied successfully in evaluating the in vitro release of the drug.

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confidence: 99%

“…A typical example of the exploitation of the properties of fluorinated compounds in ion-interaction chromatography involves the use of the fluorinated carboxylic acids, including the widely used trifluoroacetic acid, with the main advantages of these anionic ion-interaction reagents over their sulfonic acid counterparts being their volatility and therefore compatibility with ESIMS detection as well as their relatively short equilibration times. , More recently, the use of fluorinated alcohols as weakly acidic volatile anionic ion-interaction reagents has been described. , Volatile cationic di- and trialkylamine ion-interaction reagents were also described as alternatives to tetraalkylammonium salts . Despite providing significantly higher sensitivity than tetraalkylammonium salts in ESIMS, these reagents were still associated with signal suppression by 3 to 4 fold, and similarly to tetraalkylammonium, their chromatographic equilibration times are proportional to their carbon content and therefore ion-interaction capacity, with the most common compromise in this respect being triethylamine …”

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confidence: 99%

“…20 Despite providing significantly higher sensitivity than tetraalkylammonium salts in ESIMS, these reagents were still associated with signal suppression by 3 to 4 fold, 8 and similarly to tetraalkylammonium, their chromatographic equilibration times are proportional to their carbon content and therefore ion-interaction capacity, with the most common compromise in this respect being triethylamine. 21 Driven by some of the positive aspects and widespread use of the fluorinated carboxylic acids in reversed-phase chromatography, the aim of the present work was to investigate the use of commercially available fluoroalkylamine compounds as cationic ion-interaction reagents. This application of the fluoroalkylamines was not described before, and there has been a single report about the incorporation of a fluoroalkylamine in liquid chromatography, in which Kamiusuki et al briefly mentioned the addition of heptafluorobutylamine to the mobile phase as a "masking agent of the adsorption point" within the course of a study that involved investigating the retention behavior of organic compounds on a polyfluoroalkylsilane stationary phase in an attempt to achieve an improvement in the separation of three fluoroaniline isomers.…”

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confidence: 99%

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Fluoroalkylamines: Novel, Highly Volatile, Fast-Equilibrating, and Electrospray Ionization–Mass Spectrometry Signal-Enhancing Cationic Ion-Interaction Reagents

Lajin

Goessler

2020

Anal. Chem.

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A new class of cationic ion-interaction reagents for reversed-phase chromatography is introduced in the present work. Compounds belonging to a homologous series of linear fluoroalkyl chains including trifluoroethylamine (TFEAm), pentafluoropropylamine (PFPAm), heptafluorobutylamine (HFBAm), and nonafluoropentylamine (NFPAm) were tested and compared with ammonia and triethylamine (TEA) for the separation of selected organic acids of general interest such as the herbicides glyphosate, ethephon, and fosamine and arsenic metabolites methylarsonic acid and dimethylarsinic acid as well as other compounds. Depending on the carbon and fluorine atom number, the fluoroalkylamines were shown to be effective cationic ion-interaction reagents, significantly enhancing the retention of organic acids on a C18 reversed-phase column. Contrary to the general behavior of ion-interaction reagents (a broader term than ion-pairing reagent), significant (up to 5-fold) and consistent enhancement in the electrospray ionization mass spectrometry signal (ESI-MS) was observed relative to ammonia and triethylamine. Overall, among the tested series HFBAm was found to offer the best overall properties among the tested series as it provided a good compromise between column equilibration time (ca. 25 column volumes) and retention behavior (up to a 10-fold increase in the retention factor of acids relative to ammonia) while providing the same general advantages found for the fluoroalkylamines such as fast washout times from the ESIMS system (ca. 30 min) and a 3–5-fold signal enhancement. The fluoroalkylamines are a new class of cationic ion-interaction reagents with clear advantages over the currently employed alkylamines and may revive the general interest in ion-interaction chromatography.

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Use of Triethylamine as an Ion-Pairing Reagent

Cited by 11 publications

References 15 publications

Single-nucleotide resolution of RNAs up to 59 nucleotides by high-performance liquid chromatography

Single-nucleotide resolution of RNAs up to 59 nucleotides by high-performance liquid chromatography

Validation of an RP-HPLC Method for the Determination of Asenapine Maleate in Dissolution Media and Application to Study In Vitro Release from Co-Crystals

Fluoroalkylamines: Novel, Highly Volatile, Fast-Equilibrating, and Electrospray Ionization–Mass Spectrometry Signal-Enhancing Cationic Ion-Interaction Reagents

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