Mixed‐mode separation of polycyclic aromatic hydrocarbons (PAHs) in electrokinetic chromatography

Abstract

A mixed-mode separation technique has been developed and optimized for the separation of the 16 Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs). The procedure utilized two different buffer additives as pseudo-stationary phases with different selectivities towards the analytes. Sodium dioctyl sulfosuccinate (DOSS) displayed selectivities for PAHs which were somewhat similar to the C18 phase in reversed-phase high performance liquid chromatography (HPLC). High acetonitrile content required for an effective separation prevented the formation of micelles as confirmed by fluorescence spectroscopy. Consequently, the separation could be attributed to the solvophobic association of the PAH molecules with hydrophobic chains of the DOSS surfactant. In another mode of separation, sulfobutylether-beta-cyclodextrin (SB-beta-CD) separated the 16 PAHs on the formation of inclusion complexes with the PAHs, and exhibited different selectivities for the PAHs compared to DOSS. SB-beta-CD and DOSS were then combined in the running buffer to form a mixed pseudo-stationary phase for the separation of the 16 PAHs. Due to the different selectivities of SB-beta-CD and DOSS for the PAHs, the separation of the 16 PAHs was appreciably improved compared to that using DOSS or SB-beta-CD alone. All the 16 PAHs were baseline-resolved using an optimized running buffer containing 22.5 mM DOSS, 15 mM SB-beta-CD, 15% acetonitrile and 5 mM hydroxypropyl-beta-cyclodextrin in 6 mM borate at pH 9.

Analysis of insecticidal proteins from Bacillus thuringiensis and recombinant Escherichia coli by capillary electrokinetic chromatography

“…Adding methyl-b-cyclodextrin (5 mM) or negatively charged sulfobutyl ether-b-cyclodextrin (10 mM) to the SDS-containing running buffer exhibited no further beneficial effect. Notice that differential partitioning between neutral/charged cyclodextrins and negatively charged surfactants has often been shown to improve the separation of similar and neutral compounds such as polyaromatic hydrocarbons (PAHs) [20].…”

Resolution of ketoconazole enantiomers by high-performance liquid chromatography and inclusion complex formation between selector and enantiomers

“…The native cyclodextrin can be modified to expand its application. For example, cyclodextrin modified by the sulpho group (SBE-β-CD) has previously been used for enantio-separation (Lerch & Blaschke, 1998;Luong & Guo, 1998;Guan et al, 2008) and a good separation efficiency was obtained. Molecular recognition, especially chiral recognition, by native and modified *Corresponding author, e-mail: cxm@xtu.edu.cn, chenchunyan@xtu.edu.cn Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 7/1/15 3:25 PM cyclodextrins has long been of interest in supramolecular chemistry (Wang et al, 2014;Tao et al, 2014;Liu et al, 2014).…”

Monomeric and polymeric anionic gemini surfactants and mixed surfactant systems in micellar electrokinetic chromatography. Part I: Characterization and application as novel pseudostationary phases

“…Sodium dodecyl sulfate (SDS) has been widely used as a micelle-forming additive (i.e., pseudostationary phase) in micellar electrokinetic chromatography (MEKC). In addition, several different types of anionic surfactants, such as bile salts [3,4], as well as some double chain surfactants, such as disodium 5,12-bis(dodecyloxymethyl)-4,7,10,13-tetraoxa-1,16-hexadecanedisulfate [5], sodium dioctyl sulfosuccinate [6][7][8], and di(2-ethylhexyl) phosphate [9], have been also used in MEKC as pseudostationary phases. As alternatives to conventional micelles, polymeric surfactants [10][11][12][13][14][15][16][17][18][19][20][21] offer a simple and convenient way to organize surfactant monomers in MEKC.…”