Phase For Gas Chromatographic Separations Research Articles

A chiral metal–organic polyhedron used as stationary phase for gas chromatographic separations

Metal-organic polyhedra (MOPs), as a novel class of porous materials, exhibit distinctive application potential in molecular recognition, separation, catalysis, luminescent materials, drug delivery, and biomedicine owing to their tunable geometric shape and size, well-defined cavities, and discrete characteristics. In this study, we report that a chiral MOP [Cu12(LV)12(H2O)12] (V = L-valine) coated capillary column was used for gas chromatographic separations. The MOP coated capillary column offered the efficient separation of n-alkanes, alkylbenzenes, n-alcohols, multiple types of isomers, and enantiomers with high selectivity. Various enantiomers including esters, halogenated hydrocarbons, alcohols, ethers, aldehydes, and amino acid derivatives were well resolved on this chiral column, especially for some amino acid derivatives (e.g., Rs = 5.24 for tyrosine derivative). Compared with the commercial β-DEX 120 column for separation of the tested racemates, the chiral resolution performance of the MOP coated column can be complementary to that of β-DEX 120 column. Using 1,2-dichloropropane and o, m, p-dichlorobenzene as analytes, the MOP coated column exhibited good stability and reproducibility for gas chromatographic separations. The relative standard deviations (RSDs) of the retention time and peak area for repeated separation of 1, 2-dichloropropane and o, m, p-dichlorobenzene were less than 1.15 and 0.79 %, respectively. The results show that the chiral MOP holds great potential as a novel type of CSP for application in gas chromatography.

A new organic soluble cucurbit[7]uril-truxene derivative as stationary phase for gas chromatographic separation of some challenging isomers

The insolubility of parent cucurbit[n]uril or substituted-cucurbit[n]uril derivatives in organic solvents has always been a key factor restricting the column efficiency and selectivity of capillary gas chromatography column based on cucurbit[n]uril. In this work, a novel organic soluble cucurbit [7]uril-truxene derivative (Q [7]-Tr) was synthesized by Heck coupling reaction between the mono-iodinated hexahexyl-truxene and 4-vinylbenzyloxy-Q [7]. A capillary gas chromatographic column was prepared by static method with this derivative as stationary phase. The column exhibited moderate polarity and an efficiency of 5857 plates/m using n-dodecane as analyte at 120 °C, indicating the highest column efficiency of all the based-cucurbit[n]uril columns published. The Q [7]-Tr column showed high resolutions for a wide range of analytes with different polarities and better separated selectivity towards tough isomers such as aromatic amines isomers and xylene isomers compared to commercial HP-5, DB-35, Stabilwax and Q [7]-based columns. Moreover, the new column exhibited high thermal stability up to 320 °C and excellent repeatability, demonstrating a great potential as a new stationary phase in capillary gas chromatography.

Quantitative analysis of hydrogen isotopes gas mixtures by cryogenic chromatography using low loading MOFs as stationary phase

Cryogenic gas chromatography is one of the most extensively used methods for quantitative analysis of hydrogen isotopes gas mixtures. However, limitations such as long retention time or low separation resolution exist in the current chromatographic analysis for hydrogen isotope. Due to chemical affinity quantum sieving effect, MOFs materials with open metal sites show good separation performance for hydrogen isotopes. Herein, low loading composites Ni2Cl2[email protected]γ-Al2O3 was prepared by hydrothermal synthesis, which has been subsequently employed as a stationary phase for gas chromatographic separations of ternary hydrogen isotope gas mixtures (H2-HD-D2). Excellent separation resolution at liquid nitrogen temperature was realized, and baseline separation (R = 1.57) of H2/HD can be obtained within 11 min. Finally, quantitative analysis of hydrogen isotopes gas mixtures with the good accuracy and repeatability (RSD around 1%) was achieved. Compared with the traditional gas chromatography stationary phase, a shorter packed column of low loading MOFs modified composite showed high efficiency quantitative analysis for hydrogen isotopes gas mixtures.

Polysiloxane assisted fabrication of chiral crystal sponge coated capillary column for chiral gas chromatographic separation

Chiral crystalline sponges (CCSs) are a recent class of chiral porous metal complexes potential in chiral recognition. Here we report the fabrication of polysiloxane OV-1701 incorporated CCS-3S (PSO/CCS-3S) coated capillary column as a novel stationary phase for gas chromatographic separation of diverse racemates. CCS-3S with the chiral ligand of (S)-mandelic was selected as the model CCS. With the aid of polysiloxane OV-1701, PSO/CCS-3S coated capillary column gave improved resolution, broader enantiomers separation scope and much larger McReynolds constants than CCS-3S coated capillary column. Many racemates that cannot be separated on CCS-3S coated capillary column were well resolved on PSO/CCS-3S coated capillary column. The PSO/CCS-3S coated capillary column also gave wide linear range, low limit of detection, good repeatability and reproducibility, and fine inertness and anti-column bleeding properties for the separation of enantiomers. In addition, the PSO/CCS-3S coated capillary column presented better resolution for the studied racemates than commercial β-cyclodextrin based Cyclosil B (30 m long ×0.32 mm i.d. × 0.25 μm film thickness), β-DEX 225 (30 m long ×0.25 mm i.d. × 0.25 μm film thickness) and amino acid based Chirasil L-Val (25 m long ×0.25 mm i.d. × 0.12 μm film thickness) capillary columns. These results indicate the great potential of PSO/CCS-3S coated capillary column in separation of enantiomers.

P-Nitro-tetradecyloxy-calix[4]arene as a highly selective stationary phase for gas chromatographic separations

Here, we report the first example of the utilization of p-nitro-tetradecyloxy-calix[4]arene (C4A-NO2) as a stationary phase for capillary gas chromatographic (GC) separations.

Poly(3-hexylthiophene) stationary phase for gas chromatographic separations of aliphatic and aromatic isomers

This work describes the investigation of utilizing a chain-typed thiophene-based π-conjugated polymer, i.e., poly(3-hexylthiophene) (P3HT), as the stationary phase for gas chromatography (GC). The P3HT column was statically prepared and investigated for its column efficiency, polarity, separation performance, repeatability and thermal stability. As a result, it showed moderate polarity and column efficiencies of 3260, 3310 and 3790 plates/m for 1-octanol, naphthalene and n-dodecane, respectively. As evidenced, it exhibited high-resolution performance for aliphatic and aromatic isomers, including those critical pairs such as phenanthrene/anthracene and p-/m-benzenediol isomers. Moreover, it displayed stronger retention for alkanes, alcohols and phenols in comparison to the polysiloxane stationary phase with close polarity. Also, the P3HT column had good repeatability and reproducibility with the RSD values less than 0.05% for run-to-run, 0.17–0.54% for day-to-day and 2.7–5.2% for column-to-column, and good thermal stability up to 260 °C. This work demonstrates the promising future of the thiophene-based polymer and its derivatives in separation science.

Capillary column coated with geminal ionic liquids as stationary phases for gas chromatographic separation

Four geminal ionic liquids (GILs), namely, 1,4-bis(1,1′-butyl-3,3′- methylene- imidazolium)-benzene bis[(trifluoromethyl)sulfonyl]imide (BBMIB-NTf2), 1,4- bis(1,1′-butyl-3,3′-methylene-imidazolium)-benzene tetrafluoroborate (BBMIB-BF4), 1,4- bis(1,1′-butyl-3,3′-methylene-imidazolium)-benzene hexafluophosphate (BBMIB-PF6), and 1,4-bis(1,1′-methyl-3,3′-methylene-imidazolium)-benzene bis[(trifluoromethyl) sulfonyl] imide (BMMIB-NTf2), were synthesized. They were statically coated onto the inner walls of fused-silica capillary columns and used as stationary phases for gas chromatography. The evaluation of BBMIB-NTf2, BBMIB-BF4, BBMIB-PF6, and BMMIB-NTf2 as stationary phases is reported here for the first time. These new stationary phases exhibit efficiencies of at least 2.3 × 103 plates per meter. Abraham solvation parameter model was used to evaluate the solvation characteristics. The system constants indicated that the dipolarity/polarizability and the hydrogen-bond basicity play a major role among five molecular interactions between stationary phases and solute molecules. A fundamental understanding into the solvation characteristics of these GILs can be used as a guide to choosing the appropriate geminal ionic liquids for specific applications in various fields. The chromatographic separation performance was evaluated by a Grob test mixture, n-alkanes, alcohols, and aromatic isomers. Furthermore, the thermal stability was tested. The present results demonstrate that these geminal ionic liquids stationary phases possess excellent chromatographic separation performance and good thermal stability (at least up to 270 °C) and may be applicable as gas chromatography stationary phases for more application.

Separation performance of a large π-conjugated truxene-based dendrimer as stationary phase for gas chromatography

High-resolution performance of a π-conjugated truxene-based dendrimer as the stationary phase for gas chromatographic separations.

A graphene-based porous carbon material as a stationary phase for gas chromatographic separations

The GPCM column exhibits high resolving capability for structural and positional isomers from nonpolar to polar nature.

Graphitic carbon nitride as high-resolution stationary phase for gas chromatographic separations

This work presents the first example of utilization of graphitic carbon nitride (g-C3N4) as stationary phase for capillary gas chromatographic (GC) separations. The statically coated g-C3N4 column showed the column efficiencies of 3760 plates/m and weak polarity. Its resolving capability and retention behaviours were investigated by using the Grob test mixture, and mixtures of diverse types of analytes, and structural and positional isomers. The results showed superior separation performance of the g-C3N4 stationary phase for some critical analytes and preferential retention for aromatic analytes. Specifically, it exhibited high-resolution capability for aromatic and aliphatic isomers such as methylnaphthalenes and dimethylnaphthalenes, phenanthrene and anthracene and alkane isomers. In addition, g-C3N4 column showed excellent thermal stability up to 280°C and good repeatability with relative standard deviation (RSD) values less than 0.09% for intra-day, below 0.23% for inter-day and in the range of 1.9–8.4% for between-column, respectively. The advantageous separation performance shows the potential of g-C3N4 and related materials as stationary phase in GC and other separation technologies.

Cyclotriveratrylene as a new-type stationary phase for gas chromatographic separations of halogenated compounds and isomers

Cyclotriveratrylene (CTV) is reported here for the first time as stationary phase for capillary gas chromatographic (GC) separations. CTV stationary phase showed weak polarity comparable to the conventional 5% phenyl polysiloxane stationary phase but exhibited different retention behaviours and higher resolution for some of the indicated analytes. Most importantly, CTV stationary phase exhibited preferential selectivity for halogenated compounds, positional and geometrical isomers. Effect of column temperature on retention and thermal stability of CTV column were also investigated. Moreover, CTV capillary column showed good repeatability in terms of run-to-run, day-to-day and column-to-column. The unique physicochemical features and efficient separation ability for analytes of close properties show the potential of CTV as a new-type stationary phase in GC as well as separation science.

Chiral porous organic frameworks for asymmetric heterogeneous catalysis and gas chromatographic separation.

Three chiral robust diene-based porous organic frameworks (POFs) are prepared. POF- is shown to be an efficient heterogeneous catalyst after metallation for asymmetric conjugation addition with up to 93% ee, and it can also function as a new chiral stationary phase for gas chromatographic separation of racemates.

Improving selectivity in gas chromatography by using chemically modified multi-walled carbon nanotubes as stationary phase

Amino-terminated alkyl MWCNTs (MWCNTs-R-NH(2)), synthesized by chemical modification of the nanotube skeleton by nucleophilic substitution with 2,2'-(ethylenedioxy)diethylamine, were successfully used as stationary phases for gas chromatographic separation of esters and chloroaromatics. The presence of alkyl chains with polar embedded groups made the functionalized MWCNTs (f-MWCNTs) a mixed-mode GC separation material able to interact in different ways with the analytes. Compared with non-functionalized MWCNTs (nf-MWCNTs), MWCNTs-R-NH(2) had higher selectivity, enhanced resolution, and optimum retention behaviour, and they were proved to perform better than the commercial stationary phase Porapak QS (PQS), claimed to be suitable for similar applications. The so-prepared stationary phase was used for analysis of a synthetic mixture containing different classes of analytes, viz. esters, ketones, alcohols, alkanes, and aromatic hydrocarbons, and finally used for investigation of similar real matrices. In particular, the constituents of a commercial paint thinner were determined by direct injection of the sample, with good reproducibility (inter-day precision RSDs from 5 to 19%). Two unknown samples of commercial white spirit were also analysed for determination of the aromatic hydrocarbon content, and their composition was profiled on the basis of the different compounds identified.

Dual Fiber-In-capillary Annular Column with Ternary Stationary Phase for Gas Chromatographic Separation

In the present work a novel strategy for improving and/or tuning the selectivity of gas chromatographic (GC) separation by combining three different stationary phases (SPs) without premixing was introduced. A fused silica fiber coated with polydimethylsiloxane (SE30) and another coated with cyanopropylphenylmethylpolysiloxane (OV1701) were serially inserted into an 8-m polyethylene glycol 20 M (PEG20M) capillary column to form a GC annular column with ternary SP, abbreviating as SE30-OV1701-CF/PEG20M-CC. The separation capability of this ternary SP annular column was compared with a SE30-coated fiber-in-PEG20M-coated capillary annular column and a PEG20M-coated open tubular column by a test mixture of 19 organic compounds. Among these three columns, SE30-OV1701-CF/PEG20M-CC produced the best separation when the SE30-coated fiber and OV1701-coated fiber was 3 and 5 m, respectively. Selectivity can be easily tuned by changing the length of the SP-coated fibers in the ternary SP annular column. The proposed ternary SP annular column shows additional tunability, thus making it a promising tool for separation of organic solvents that are often used in the manufacturing process of pharmaceutical formulations and lacquer thinners.

Highly selective liquid crystalline polysiloxane stationary phase for gas chromatographic separation of isomers

The gas chromatographic isomeric selectivity (for p- and m-xylene) of six mesogenic monomers and polysiloxanes having various side-chains, degrees of polymerization and linking ester groups (- OOC- and -COO-) were investigated. The results indicate that the polymeric stationary phases had higher isomeric selectivities. The highest selectivity coefficient for p- and m-xylene, α =1.21, was obtained at 65°C for the polymeric stationary phase [4-octyloxy(4-allyloxyphenyl benzoate)] polymethylhydrogensiloxane (POBAP-20) with an optimized film thickness of 0.63 μm.

Eutectic inorganic salt melts as stationary phases for gas chromatographic separation of high-boiling hydrocarbons

The thermal stability of nine eutectic inorganic salts with melting temperatures between 80 and 180°C was evaluated. The contact angles of six of these salt melts on glass and PTFE are similar to that of 1,2,3-tris-(2-cyanoethoxy)propane, a strongly polar organic phase. Packed and capillary columns with salt melts as stationary phase were prepared. It appears that the retention mechanism of hydrocarbons on salt melts is dominated by adsorption at the liquid surface. The separation is strongly dependent on the sample size. Packed columns with 700 and capillary columns with up to 2000 theoretical plates per metre could be prepared. An example is given of the separation of a n-alkane mixture with an average molecular weight of 628.

Liquid Phase for Gas Chromatographic Separation of Lower Hydrocarbons

The half dimethylamide of ethyl oxalate (ethyl N,N-dimethyloxamate) is used for the GC separation of C1-C4 hydrocarbons. Commercially available solid supports are used without special treatment, and the columns have a long life if the temperature is maintained at 0°C. This liquid phase is used in the acetylene-ethylene assay for nitrogen fixation reported by Hardy et al. (3). The preparation of the compound and of the column packing is given in detail.

Gas chromatography ofCis‐Trans fatty acid isomers on nitrile silicone capillary columns

AbstractThree nitrile silicone polymers have been evaluated as liquid phases for gas chromatographic separation of the geometric isomers of methyl oleate, methyl linoleate, and methyl linolenate on capillary columns. A polymer of ॆ‐cyanoethylmethylsiloxane proved the most effective. This liquid phase separated oleate from elaidate, resolved the four geometric isomers of linoleate into three peaks, and divided the eight geometric isomers of linolenate into six peaks. Two other copolymers of dimethylsiloxane and ॆ‐cyanoethylmethylsiloxane gave poorer resolution ofcis‐trans isomers, but showed different elution patterns for the geometric isomers of linoleate and linolenate.

A NEW LIQUID PHASE FOR GAS CHROMATOGRAPHIC SEPARATIONS OF STEROIDS

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA NEW LIQUID PHASE FOR GAS CHROMATOGRAPHIC SEPARATIONS OF STEROIDSW. J. A. VandenHeuvel, E. O. A. Haahtl, and E. C. HorningCite this: J. Am. Chem. Soc. 1961, 83, 6, 1513–1514Publication Date (Print):March 1, 1961Publication History Published online1 May 2002Published inissue 1 March 1961https://doi.org/10.1021/ja01467a054RIGHTS & PERMISSIONSArticle Views39Altmetric-Citations100LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (275 KB) Get e-Alerts Get e-Alerts