Extraction of metals from aqueous systems employing capillary-channeled polymer (C-CP) fibers modified with poly(acrylic acid) (PAA)

Abstract

Polyethylene terephthalate (PET, polyester) capillary-channeled polymer (C-CP) fibers were employed as the base structure for surface modification to provide a sorbent for solid phase extraction (SPE) of aqueous cations. Surface functionalization with polyacrylic acid (PAA) was achieved using a ''grafting to'' approach, yielding a stable sorbent that has the potential of being employed over a large range of pH values and a variety of sample matrices. PAA was chosen for surface modification because the repeating acrylic acid monomeric unit, which contains a carboxylic acid, has the ability to bind metal ions. In a micropipette-tip SPE format, these PAA-functionalized C-CP fibers showed the ability to efficiently bind several metals (Cu 2+ , Cu + , Ni 2+ , Fe 3+ , UO 2 2+ ), while elution could be achieved with extremely low concentrations of hydrochloric acid (1 ml of 0.005%), resulting in overall recoveries of greater than 88%. A single tip was carried throughout the entire study as a control, and showed overall recoveries averaging 96% over the course of 19 extraction experiments and a 12-month period, demonstrating the chemical stability of the sorbent material, and suggesting the potential of the C-CP fiber SPE tips to be used multiple times.

Initial evaluation of protein A modified capillary-channeled polymer fibers for the capture and recovery of immunoglobulin G

“…The column was cut into 2.54 cm segments with an additional 4-mm gap left at one end allowing for the tubing to be press-fit onto the end of a low-retention 1 mL micropipette tip (Redi-Tip, Fisher Scientific). This fiber tip format has been described previously and successfully applied in our laboratory for SPE [14][15][16]. The weight of fiber stationary phase per 2.54 cm tip is 4.0 ± 0.1 mg. Figure 1 provides successive viewpoints of the C-CP fiber tip structure, from the assembled SPE tip down to the single-fiber level.…”

Evaluation of loading characteristics and IgG binding performance of Staphylococcal protein A on polypropylene capillary-channeled polymer fibers

“…However, many of these derivatization methods can be detrimental to the physical properties of the polymer by destroying the polymer backbone. In order to further exploit the advantageous fluidic properties of C-CP fiber columns without compromising their mechanical strength, milder modification approaches have been a focus of this group recently, including covalent coupling [25][26][27] and direct ligand adsorption methods [28][29][30]. Among recent work was the demonstration of a simple modification of PP C-CP fibers with protein A by direct adsorption for the capture of IgG [31].…”

Capillary-Channeled Polymer (C-CP) Fibers as a Stationary Phase for Sample Clean-Up of Protein Solutions for Matrix-Assisted Laser/Desorption Ionization Mass Spectrometry

“…A centrifugation-based approach as been implemented, resulting in higher sample throughput through parallel processing and greater levels of experimental control [16]. A pipette tip adapter was made so the fiber-packed tips could be placed into a six-bucket benchtop centrifuge (Clinical 50; VWR, West Chester, PA, USA).…”

“…A new protocol for the SPE processing, employing a simple centrifugation method, provides far greater sample throughput and overall superior precision than manual aspiration [15,16]. Efficient desalting is performed for proteins (cytochrome c and lysozyme) on the sub-micromolar level (nanogram absolute mass) in the presence of up to 1 M Tris-HCl.…”