Journal of Chromatography A, 1216 (2009) 772–780 Contents lists available at ScienceDirect Journal of Chromatography A journal homepage: www.elsevier.com/locate/chroma Development of fluorinated, monolithic columns for improved chromatographic separations of fluorous-tagged analytes Adam B. Daley, Richard D. Oleschuk ∗ Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, ON K7L 3N6, Canada article info Article history: Received 3 September 2008 Received in revised form 10 November 2008 Accepted 17 November 2008 Available online 3 December 2008 Keywords: Fluorous chemistry Porous polymer monolith Affinity separation Liquid chromatography abstract With applications that take advantage of highly selective fluorine–fluorine interactions appearing with greater frequency in the literature, the development of porous polymer monoliths from fluorous com- ponents is reported here for the purpose of chromatography of tagged analytes. With potential uses in fields as diverse as separation science and proteomics, facile fabrication of materials with fluorous specificity that can be applied in a high-throughput manner is greatly desirable. To this end, we have developed porous polymer capillary columns with varied fluorous content using a simple UV-initiated radical polymerization process and characterized them using flow-induced backpressure and scanning electron microscopy (SEM). With structural similarities assured (visually, and by backpressure varia- tions of less than 42%), the monoliths were tested as chromatographic columns for the separation of a series of fluorous-tagged analytes under gradient conditions. It was found that columns made with fluori- nated components exhibited greater selectivity for fluorous analytes than did equivalent, non-fluorinated monoliths, retaining analytes with either one or two fluorous tags for approximately 6% and 13% longer, respectively. This supports the idea of differences existing between fluorous and reverse-phase separa- tion mechanisms, and encourages a broader range of potential applications for fluorous monoliths of this type. © 2008 Elsevier B.V. All rights reserved. 1. Introduction Although originally devised and applied as a novel tool to facil- itate liquid–liquid biphase extractions [1], the concept of fluorous chemistry has greatly expanded in both scope and application in the roughly 14 years since that seminal publication. Particularly interesting is the idea of fluorous solid-phase extraction (FSPE), which allows the selective isolation of fluorinated targets from convoluted mixtures through the use of fluorous silica gel and highly specific fluorous–fluorous interactions [2–4]. Recent work has shown that this idea holds great potential for proteomic appli- cations such as the purification of oligonucleotides [5] and peptides [6], where posttranslational modifications can become target sites for the addition of fluorous tags to facilitate separations. Addition- ally, this method has been shown to have benefits over some of the more conventional proteomic labelling techniques in terms of cost, ease of use and specificity [7,8], as well as providing better complex stability during analysis by mass spectrometry such that spectra exhibit less fragmentation and are consequently easier to interpret [6]. ∗ Corresponding author. Tel.: +1 613 533 6704; fax: +1 613 533 6669. E-mail address: oleschuk@chem.queensu.ca (R.D. Oleschuk). While the idea of FSPE is obviously beneficial for a number of applications, it also makes sense to try and extend it into the realm of chromatography such that separations can be performed in tan- dem with analyte identification to improve sampling throughput. Although columns with fluorinated bonded-phases are known in the literature, they are frequently used in applications that are unable to take advantage of their unique fluorous-fluorous separa- tion properties, instead choosing to direct their focus toward other analytes [9–11]. Additionally, packed chromatographic columns often suffer from limitations such as the packing density of the par- ticles, void formation and increasing backpressure as particle sizes decrease, making them less than ideal even when they are paired with the proper application. It is in this realm that monolithic mate- rials begin to show their advantage, since they do not share these same restrictions. Porous polymer monolith (PPM) technology was largely devel- oped as an alternative to conventional packed columns, possessing a continuous porous structure and extremely low flow-induced backpressure for their relative column length and size [12,13]. Traditionally formed using thermally-initiated free radical poly- merization of a mixture of monomers, cross-linking agent and porogenic solvent [14], the technique allowed the patterning of a monolith within a specified vessel with relative ease as com- pared to microsphere packing [15]. Expanding the scope to include 0021-9673/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.chroma.2008.11.078