Development of fluorous porous polymer monolith (FPPM) for the capillary electrochromatographic separation of fluorous analytes based on fluorous–fluorous interaction

Abstract

This is the first report on the CEC separation of fluorous analytes on a fluorous porous polymer monolith (FPPM) stationary phase based on fluorous-fluorous interaction. Monolithic columns do not require retaining frits and can be conveniently photo-patterned within a capillary. Two groups of fluorous compounds, a N-f-Cbz-4-nitro-benzylamine (N) series and a N-f-Cbz-4-phenyl-benzylamine (P) series, each series having compounds differing only by the length of their perfluorinated tag, were employed to evaluate the ability of the fluorinated column to separate fluorous analytes using a variety of mobile phase compositions and separation conditions. Fluorous monoliths showed enhanced separation performance by providing better selectivity, higher resolution and shorter analysis time compared to a similar non-fluorous (reversed phase) monolithic column. Under optimal conditions, column efficiency as high as 234,000 plates per metre was achieved, and all four compounds of the N series were fully resolved in <5 minutes. Perfluoromethylene selectivity was used to quantitatively evaluate the interaction between the perfluorinated chain on the analytes and both the FPPM and non-FPPM columns. It was found that the non-FPPM column resolves fluorous analytes mainly based on reversed phase interaction while the FPPM column resolves them mainly based on fluorous-fluorous interaction. Results are compared to fluorous monolith columns used in a nano-liquid-chromatographic (nano-LC) separation with gradient elution. The FPPM column required less than one fifth the analysis time in CEC mode than was required in nanoLC mode, with superior separation efficiency and resolution. FPPM stationary phases provide an attractive option for the analysis of perfluorinated analytes, which is expected to be useful in areas such as proteomics for the separation of fluorously tagged proteins, and in environmental analysis where fluorinated species are of increasing concern.

Magnetic droplet actuation on natural (Colocasia leaf) and fluorinated silica nanoparticle superhydrophobic surfaces

“…Methanol droplets, on the other hand, almost completely wetted the FSNP surface, leading to CAs <10 • . Increased wetting of these solvents on a fluorous surface is not surprising as methanol, and to a lesser extent ACN, are considered "fluorophilic" solvents commonly used in fluorous-phase chromatography [42]. In the case of UED, where fluorous particles are affixed to a surface with a bonding material, wetting of the surface with organic solvents leads to the particles becoming dislodged and the bonding material being damaged.…”

Strong and small: strong cation-exchange solid-phase extractions using porous polymer monoliths on a digital microfluidic platform

“…38,[40][41][42][43][44][45][46][47][48] Recently, we presented the first application for PPMs on DMF 36 using PPM discs with C12 moieties as a reverse phase for SPE. With the goal of expanding this technique to include SCX extractions, Fig.…”

Search for improved fluorinated stationary phases for separation of fluorine-containing pharmaceuticals from their desfluoro analogs

“…The use of fluorinated stationary phases for the chromatographic separation of fluorine-containing compounds and the broader topic of fluorophilic adsorption has been well studied, most notably by Curran and co-workers [12][13][14]. Fluorinated stationary phases have gained increasing importance in LC separations because they offer selectivity that is orthogonal to traditional alkyl phases, which operate predominately by hydrophobic interaction mechanisms.…”