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Separations of isomer mixtures of (a) hexane, (b) heptane, (c) octane, (d) trimethylbenzene (e) propylbenzene and butylbenzene, (f) trichlorobenzene, (g) methylnaphthalene isomers, (h) dimethylnaphthalene, (i) dimethylphenol, (j) nitrobenzaldehyde, (k) dichlorobenzaldehyde, and (l) lodoaniline on PFs column. Temperature program for (a): 50 C; for (b): 40 C (1 min) to 70 C at 10 C min À1 ; for (c): 40 C (1 min) to 90 C at 10 C min À1 ; for (d): 130 C; for (e): 40 C (1 min) to 130 C at 10 C min À1 ; for (f): 120 C; for (g): 150 C; for (h): 160 C; for (i): 160 C; for (j): 110 C (1 min) to 170 C at 10 C min À1 ; for (k): 110 C (1 min) to 170 C at 10 C min À1 ; for (l): 135 C, and flow rate at 0.6 mL min À1 .
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Herein we report the first example of exploring bio-based materials, palm fibers (PFs), as a stationary phase for capillary gas chromatographic separations. The PFs capillary column was fabricated by the sol–gel coating method and showed a weak polar nature and high column efficiency over 4699 plates per m for n-dodecane, naphthalene and n-octanol....
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... to separate compounds with close boiling points and molecular masses, especially positional and structural isomers. In this work, 12 groups of test isomer mixtures consisting of alkanes, alkyl benzenes, halogenated benzenes, phenol, naphthalene and aniline were employed to further evaluate the separation performance of PFs column. As shown in Fig. 8a-l, the PFs stationary phase achieved baseline resolution (R > 1.5) of these isomer mixtures ranging from nonpolar to polar nature with sharp peaks. Fig. 8a-c show the rapid separations of the isomers of C6-C8 alkane. van der Waals interactions may be the major driving force for the separation of alkane isomers on PFs column. Fig. 8d and ...
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... mixtures consisting of alkanes, alkyl benzenes, halogenated benzenes, phenol, naphthalene and aniline were employed to further evaluate the separation performance of PFs column. As shown in Fig. 8a-l, the PFs stationary phase achieved baseline resolution (R > 1.5) of these isomer mixtures ranging from nonpolar to polar nature with sharp peaks. Fig. 8a-c show the rapid separations of the isomers of C6-C8 alkane. van der Waals interactions may be the major driving force for the separation of alkane isomers on PFs column. Fig. 8d and e exhibit the separations of alkylated benzene isomers, such as trimethylbenzenes and propyl/butylbenzene. The high resolution for these nonpolar isomers ...
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... As shown in Fig. 8a-l, the PFs stationary phase achieved baseline resolution (R > 1.5) of these isomer mixtures ranging from nonpolar to polar nature with sharp peaks. Fig. 8a-c show the rapid separations of the isomers of C6-C8 alkane. van der Waals interactions may be the major driving force for the separation of alkane isomers on PFs column. Fig. 8d and e exhibit the separations of alkylated benzene isomers, such as trimethylbenzenes and propyl/butylbenzene. The high resolution for these nonpolar isomers demonstrated the extraordinary distinguishing capability of the PFs stationary phase through its van der Waals interactions and p-p stacking with the isomers. Also, the PFs column ...
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... benzene isomers, such as trimethylbenzenes and propyl/butylbenzene. The high resolution for these nonpolar isomers demonstrated the extraordinary distinguishing capability of the PFs stationary phase through its van der Waals interactions and p-p stacking with the isomers. Also, the PFs column well resolved the trichlorobenzenes isomers in Fig. 8f mainly due to its integrated effect of halogen-bonding and p-p EDA interactions. As shown in Fig. 8g and h, the PFs column achieved good resolution of methylnaphthalenes and dimethylnaphthalenes. H-bonding and C-H/p interactions between the stationary phase and solutes played signicant roles and made the stationary phase high ...
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... nonpolar isomers demonstrated the extraordinary distinguishing capability of the PFs stationary phase through its van der Waals interactions and p-p stacking with the isomers. Also, the PFs column well resolved the trichlorobenzenes isomers in Fig. 8f mainly due to its integrated effect of halogen-bonding and p-p EDA interactions. As shown in Fig. 8g and h, the PFs column achieved good resolution of methylnaphthalenes and dimethylnaphthalenes. H-bonding and C-H/p interactions between the stationary phase and solutes played signicant roles and made the stationary phase high sensitive to the compounds of similar structures. Aerwards, its separation capability for the isomers of ...
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... solutes played signicant roles and made the stationary phase high sensitive to the compounds of similar structures. Aerwards, its separation capability for the isomers of H-bonding type (phenols, aldehydes and anilines) was explored. The separation results for xylenols, nitrobenzaldehydes, dichlorobenzaldehydes, iodoanilines are presented in Fig. 8g-i, respectively. Noteworthy, the PFs column achieved complete separation of the above isomers that are liable to severe peak-tailing and difficult to be well resolved, and sharp symmetrical peaks were obtained. These Fig. 6 Separations of a more complex mixture containing 35 analytes of diverse types with varying polarity on PFs column. ...
Citations
... The polarity of the new stationary phases is an important GC parameter and selection in practical use. The McReynolds constant of C4RA-2IL stationary phase have been quantitatively measured at 120 °C by the five probe solutes of benzene, 1-butanol, 2-pentanone, 1-nitropropane and pyridine [44,45]. Table 1 shows the McReynolds constants determined for C4RA-2IL stationary phase; the McReynolds constants of commercial DB-1701 stationary phase are also provided for reference. ...
In this work, a novel calix[4]resorcinarene-based ionic liquid (C4RA-2IL) was synthesized, structurally characterized, and statically coated on capillary column as stationary phase for capillary gas chromatography (GC). The column efficiency of the C4RA-2IL column is 3345 plates m−1, which are determined by n-dodecane at 120 °C. Based on its McReynolds constants, the C4RA-2IL column showed moderate polarity. Particularly, the C4RA-2IL column show high separation performance for a wide range of analytes and some difficult separation of meta/para-isomers. Moreover, it exhibited excellent selectivity for critical aromatic isomers of chloroaniline, bromaniline, iodoaniline, toluidine and xylidine isomers and shows advantageous separation capability over the commercial polysiloxane stationary phase. This work presents a promising future of calixarene-based ionic liquid as a new type of stationary phase in GC separations.
... However, few of them are capable of separating the tough isomer mixtures with the similar chemical nature and polarity. For these challenging analytical tasks, our group is constantly exploring new chromatographic separation materials with special selectivity in GC. [16][17][18][19] Poly(3-caprolactone) (PCL) is a saturated aliphatic polyester consisting of hexanoate repeating units. 20 Its repeating unit contains ve non-polar methylene (-CH 2 -) and one polar ester group (-COOC-), which makes the molecular chains relatively regular. ...
This work presents the separation performance of star-poly(ε-caprolactone) (star-PCL) as the stationary phase for capillary gas chromatography (GC). The statically coated star-PCL column showed a column efficiency of 3345 plates per m and moderate polarity. Importantly, the star-PCL column exhibited high selectivity and resolving capability for more than a dozen mixtures covering a wide-ranging variety of analytes and isomers. Among them, the star-PCL column displayed advantageous resolving capability over the commercial DB-1701 column for aromatic amine isomers such as toluidine, chloroaniline and bromoaniline. Moreover, it was applied for the determination of isomer impurities in real samples, showing good potential in GC applications.
... The polarity of PCL-PEG-PCL stationary phase was evaluated by McReynolds constants of the five probe solutes, i.e., benzene (X'), 1-butanol (Y'), 2-pentanone (Z'), 1-nitropropane (U'), and pyridine (S'), and the results are provided in Table 1 [31,32].As can be seen, the PCL-PEG-PCL stationary phase has anaverage value of 351, suggesting its moderate polarity.Additionally, the Abraham system constants of the PCL-PEG-PCL stationary phase were determined at three temperatures (80 °C, 100 °C, and 120 °C) and the results are provided in Table 2 [33][34][35].Observably, the major interactions of the PCL-PEG-PCL stationary phase was H-bonding basicity (a), ...
... The polarity of PCL-PEG-PCL stationary phase was evaluated by McReynolds constants of the five probe solutes, i.e., benzene (X'), 1-butanol (Y'), 2-pentanone (Z'), 1-nitropropane (U'), and pyridine (S'), and the results are provided in Table 1 [31,32].As can be seen, the PCL-PEG-PCL stationary phase has an average value of 351, suggesting its moderate polarity. Additionally, the Abraham system constants of the PCL-PEG-PCL stationary phase were determined at three temperatures (80 • C, 100 • C, and 120 • C) and the results are provided in Table 2 [33][34][35]. ...
This work presents the first example of utilization of amphiphilic block copolymer PCL-PEG-PCL as a stationary phase for capillary gas chromatographic (GC) separations. The PCL-PEG-PCL capillary column fabricated by static coating provides a high column efficiency of 3951 plates/m for n-dodecane at 120 °C. McReynolds constants and Abraham system constants were also determined in order to evaluate the polarity and possible molecular interactions of the PCL-PEG-PCL stationary phase. Its selectivity and resolving capability were investigated by using a complex mixture covering analytes of diverse types and positional, structural, and cis-/trans-isomers. Impressively, it exhibits high resolution performance for aliphatic and aromatic isomers with diverse polarity, including those critical isomers such as butanol, dichlorobenzene, dimethylnaphthalene, xylenol, dichlorobenzaldehyde, and toluidine. Moreover, it was applied for the determination of isomer impurities in real samples, suggesting its potential for practical use. The superior separation performance demonstrates the potential of PCL-PEG-PCL and related block copolymers as stationary phases in GC and other separation technologies.
In this paper, two new amino acid imidazole ionic liquids IL‐3 and IL‐4 were synthesized for the first time, and their separation performance as the stationary phase for capillary gas chromatography (GC) was tested. The statically coated IL‐3 and IL‐4 capillary columns exhibited moderate to high polarity, and achieved the column efficiency of 2242 plates/m and 2487 plates/m respectively determined by n‐octanol at 120 °C. Importantly, the IL‐3 and IL‐4 columns exhibited excellent separation capability for analytes with varying polarity, including n‐alkanes, arenes, esters, alcohols, bromoalkanes, halogenobenzenes, and halogenated anilines. In addition, the IL‐3 and IL‐4 columns presented high selectivity and separation capability for positional, structural and cis‐/trans‐isomers. In particular, they showed high separation performance of the chloroaniline, bromaniline, iodoaniline and xylidine isomers as an important environmental pollutant. The IL‐3 and IL‐4 columns displayed advantageous resolving capability over the commercial HP‐35 column for aromatic amine isomers, and the separation performance of IL‐4 with long carbon chain was better than that of IL‐3. Moreover, it was applied to determine isomer impurities in real samples, and showing huge potential in GC applications. This work demonstrates the potential of the amino acid imidazole ionic liquids as a new type of stationary phase in GC separations.
Pillar[n]arenes possess highly symmetrical and rigid pillar-shaped architecture with π-electron rich cavity that afford their reliable host-guest recognition interactions towards matched guests. In this work, a novel amphiphilic pillar[5]arene (P5A-C10-2NH2) was designed, synthesized and employed as the stationary phase for capillary gas chromatography. To date, they have not been reported in the field of chromatography. The P5A-C10-2NH2 capillary column (10 m × 0.25 mm i.d.) was prepared by static coating method. Its capillary column exhibited moderate polarity and column efficiency of 2265 plates/m determined by naphthalene at 120°C. As evidenced, the P5A-C10-2NH2 column achieved advantageous separation performance for a mixture of 24 analytes of diverse types and exhibited different chromatographic selectivity from two pillar[5]arene derivatives columns and commercial HP-35 column with 35%-phenyl-methylpolysiloxane. Moreover, the P5A-C10-2NH2 column baseline resolved more than a dozen positional and cis-trans isomers. Furthermore, the separation mechanism of P5A-C10-2NH2 column was discussed by quantum chemical calculations. In addition, the P5A-C10-2NH2 column had high thermal stability and excellent separation repeatability 0.01%-0.04% for run-to-run, 0.03%-0.17% for day-to-day and 3.2%-3.9% for column-to-column. The special amphiphilic structure and high resolution for various analytes reveal the good potential of pillararenes as a new class of stationary phases for chromatographic analyses. Moreover, the TPG column achieved improved thermal stability over the GIL column and excellent repeatability.
The title compound, 6-(3-chloropropoxy)-4-(2-fluorophenylamino)-7-methoxyquinazoline, was synthesized by selective nucleophilic attack at C-1 of 1-bromo-3-chloropropane by the potassium salt of 4-(2-fluorophenylamino)-7-methoxyquinazolin-6-ol, which was prepared from 7-methoxy-4-oxo-3,4-dihydroquinazolin-6-yl acetate in three steps. The compound crystallized as an ethyl acetate complex (C 20 H 21 ClFN 3 O 3 , M r = 405.85), and X-ray crystallography showed that the crystal belongs to the orthorhombic system, space group Pbca with a = 12.7407(4) Å, b = 14.0058(5) Å, c = 21.7726(7) Å, α = 90°, β = 90° and γ = 90°. The whole molecule is stacked into a three-dimensional structure via weak N–H…N hydrogen bonding between molecules. The compound acts as an effective inhibitor on the proliferation of a lung cancer cell line.
Here we report the first example of employing p-nitro-octadecyloxy-calix[8]arene (C8A-NO2) as stationary phase for capillary gas chromatographic (GC) separations. The statically coated C8A-NO2 column provided column efficiencies of 2554 plates/m and showed moderate polarity. Its selectivity and retention behaviour were investigated by a number of mixtures of diverse analytes and their isomers. It was found that the C8A-NO2 column exhibited high resolving capability for aliphatic and aromatic analytes from apolar to polar nature, especially for positional and structural isomers. Among them, advantageous resolving capability over the commercial polysiloxane DB-1701 and DB-17 columns was obtained for chloroaniline and bromoaniline isomers. In addition, the C8A-NO2 column was applied for the determination of isomer impurities in commercial reagents of geraniol, cis-decahydronaphthalene, and trans-decahydronaphthalene.
This work presents the first example of the utilization of p-tert-butyl(tetradecyloxy)calix[6]arene (C6A-C10) as a stationary phase for capillary gas chromatographic (GC) separation. The statically coated C6A-C10 column showed a column efficiency of 3293 plates per m and had a nonpolar nature. Its selectivity and retention behaviour were investigated using a number of mixtures of diverse analytes and their isomers. As a result, the C6A-C10 column exhibited high resolving capability for aliphatic and aromatic analytes from apolar to polar nature, especially for positional, structural and cis-/trans-isomers. Moreover, the C6A-C10 column showed thermal stability up to 240 °C. In addition, it was applied for the determination of isomer impurities in real samples, proving its good potential for practical GC analysis.
Here we report the first example of utilization of p-nitro-tetradecyloxy-calix[4]arene (C4A-NO2) as stationary phase for capillary gas chromatographic (GC) separations. The statically coated C4A-NO2 column exhibited high column efficiency of 3815 plates/m and moderate polarity. The C4A-NO2 column was investigated for its separation performance and retention behaviours by utilizing a wide variety of isomer mixtures, covering alkylated benzenes and naphthalenes, alkenes, furan, alcohols, benzaldehydes, phenols and halogenated anilines. Importantly, C4A-NO2 column exhibited high resolving capability for both aliphatic and aromatic isomers. Particularly, it displayed advantageous resolving capability over the commercial DB-17 column for halogenated aniline isomers. This work provides a good reference for designing calixarene derivatives as GC stationary phases, which is important for developing a family of stationary phases with specific selectivity.
This work describes the separation performance of the amphiphilic star-shaped calix[4]resorcinarene (C4A-CL) as the stationary phase for capillary gas chromatography (GC). The statically coated C4A-CL capillary column exhibited medium polarity and high column efficiency of 3877 plates m⁻¹ determined by naphthalene at 120 °C. Importantly, the C4A-CL column exhibited extremely high resolving capability for aliphatic analytes with varying polarity, including n-alkanes, esters, ketones, alcohols, and bromoalkanes. In addition, the C4A-CL column exhibited high selectivity and resolving capability for positional, structural and cis-/trans-isomers. Among them, the C4A-CL column displayed advantageous resolving capability over the commercial DB-17 column for aromatic amine isomers. Moreover, it was applied for the determination of isomer impurities in real samples, showing good potential in GC applications.
