Hybrid organic monolithic column containing MIL-68(Al) for the separation of small molecules by capillary HPLC.

Publisher: Elsevier Country of Publication: Netherlands NLM ID: 9318488 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1873-3778 (Electronic) Linking ISSN: 00219673 NLM ISO Abbreviation: J Chromatogr A Subsets: MEDLINE

Original Publication: Amsterdam ; New York : Elsevier, 1993-

Metal-Organic Frameworks*/chemistry ; Polycyclic Aromatic Hydrocarbons*/isolation & purification ; Polycyclic Aromatic Hydrocarbons*/analysis ; Polycyclic Aromatic Hydrocarbons*/chemistry; Chromatography, High Pressure Liquid/methods ; Monte Carlo Method ; Phenols/isolation & purification ; Phenols/analysis ; Phenols/chemistry ; Porosity

A hybrid organic monolithic column made of poly(lauryl methacrylate-co-1,6-hexanediol dimethacrylate) and the metal-organic framework MIL-68(Al) was prepared for the first time. The column was used in capillary liquid chromatography, both in isocratic and gradient elution modes. Separation performance towards small molecules of different chemical nature (polycyclic aromatic hydrocarbons, alkylbenzenes, phenols, etc.) was studied. Monte Carlo simulations were made to both select the proper precursors to obtain empty metal-organic framework micropores in the monolithic polymer and also, to analyze the potential free access of the studied analytes into the micropores (necessary to improve mass transfer and column efficiency). The hereby synthesized metal-organic framework microcrystals allowed obtaining homogeneous hybrid monolithic columns. Adding of MIL-68(Al) (1030 m ² g ^-1 BET specific surface area) increased the surface area from 3.9 m ² g ^-1 for the parent monolith to 18.2 m ² g ^-1 for the hybrid column containing 8 mg mL ^-1 of the microcrystals. Chromatographic performance of this new column was evaluated by studying retention factors, resolution, and plate counts at room temperature. Different compounds, not completely resolved in the parent monolith, were partially or completely separated after metal-organic framework addition. Using the monolithic column with only 2 mg mL ^-1 of MIL-68(Al), five alkylbenzenes were completely separated with very symmetrical peak shapes, resolution factors up to 3.60 and plate counts of 4300 plates m ^-1 for n-hexylbenzene. This value is higher than those obtained by other authors who used organic monolithic columns with embedded metal-organic frameworks to perform separations at room temperature. Additionally, nine polycyclic aromatic hydrocarbons were partially or completely resolved in gradient elution mode. The hybrid monolithic columns exhibited very good intra-day (%RSD=1.9), inter-day (%RSD=2.6), and column-to-column (%RSD=4.3) reproducibility values. Easy and fast column preparation, and versatility to efficiently separate several compounds of different chemical nature in isocratic and gradient mode, makes this new hybrid column a very good option for the analysis of small molecules in capillary (or nano) HPLC.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier B.V. All rights reserved.)

Keywords: Capillary liquid chromatography; Hybrid monolithic stationary phases; Metal-organic frameworks; Mil-68(Al); Small molecules

0 (Metal-Organic Frameworks)
0 (Polycyclic Aromatic Hydrocarbons)
0 (Phenols)

Date Created: 20240821 Date Completed: 20240905 Latest Revision: 20240905

20240905

10.1016/j.chroma.2024.465258

39167883