Open-tubular capillary electrochromatography using a polymeric surfactant coating

A stable polyelectrolyte multilayer (PEM) coating was investigated for use in open-tubular capillary electrochromatography (o-CEC). In this approach, the PEM consisted of the cationic polymer of a quaternary ammonium salt, poly(diallyldimethylammonium chloride) and the anionic polymeric surfactant, poly(sodium undecylenic sulfate). Both the cationic and anionic polymers were physically adsorbed to the surface of a fused-silica capillary by use of a simple coating procedure. This procedure involved an alternate rinse of the positively and negatively charged polymers. The performance of the PEM coating as a dynamic stationary phase was evaluated by use of electrochromatographic experiments and showed good selectivity for both phenols and benzodiazepines. Reproducibility of the PEM coating was also evaluated by calculating the relative standard deviations (RSDs) of the electroosomotic flow (EOF). The run-to-run and capillary-to-capillary RSD values of the EOF were less than 1.5%. The endurance of the coating was more than 100 runs. The importance of the PEM coating was illustrated by comparing separations on a bare uncoated capillary with the coated capillary. In addition, the chromatographic performance using o-CEC and micellar electrokinetic chromatography (MEKC) was compared for the separation of benzodiazepines.     

Electrokinetic separation of peptides and proteins using a polyvinylamine-coated capillary with UV and ESI-MS detection

In order to accomplish the analysis of peptides and proteins by capillary electrophoresis, Lupamin, a high-molecular-weight linear polyvinylamine (PVAm) polymer, was introduced to modify the inner wall of fused-silica capillaries by physical absorption. Thanks to the high density of positively charged amino groups in Lupamin under acidic conditions, not only is a strong reversed electroosmotic flow generated in the coated capillary but the adsorption of analytes on the inner wall of the capillary is also efficiently eliminated. It has been demonstrated that the Lupamin-coated capillary can be used to advantage for the rapid analysis of amino acids, peptides, and proteins with good resolution and peak shape by capillary electrophoresis. In order to evaluate the basic feature of a Lupamin-coated capillary, electroosmotic flows generated by a Lupamin coating layer under different conditions including pH, coating time, concentration, and the composition of electrolytes on Lupamin-coated and uncoated capillaries were investigated. Furthermore, electrospray ionization-mass spectrometry (ESI-MS) detection was carried out for the analysis of amino acids and peptides.     

Protein separations using polyelectrolyte multilayer coatings with molecular micelles in open tubular capillary electrochromatography

Novel polyelectrolyte multilayer (PEM) coatings for enhanced protein separations in open tubular CEC (OT-CEC) are reported. Use of four cationic polymers (poly-L-lysine, poly-L-ornithine, poly-L-lysine-serine, and poly-L-glutamic acid-lysine), and three anionic molecular micelles, sodium poly(N-undecanoyl-L-leucyl-alaninate) (poly-L-SULA), sodium poly(N-undecanoyl-L-leucyl-valinate) (poly-L-SULV), and sodium poly(undecylenic sulfate) (poly-SUS) were investigated in PEM coatings for protein separations. The simultaneous effects of cationic polymer concentration, number of bilayers, temperature, applied voltage, and pH of the BGE on the separation of four basic proteins (alpha-chymotrypsinogen A, lysozyme, ribonuclease A, and cytochrome c) were analyzed using a Box Behnken experimental design. The influence of NaCl on the run-to-run reproducibility was investigated for PEM coatings containing each cationic polymer. All coatings exhibited excellent reproducibilities with a %RSD of the EOF less than 1% in the presence of NaCl. Optimal conditions were dependent on both the cationic and anionic polymers used in the PEM coatings. Poly-L-glutamic acid-lysine produced the highest resolution and longest migration time. The use of molecular micelles to form PEM coatings resulted in better separations than single cationic coatings. Chiral poly-L-SULA and poly-L-SULV resulted in higher protein resolutions as compared to the achiral, poly-SUS. Furthermore, the use of poly-L-SULV reversed the elution order of lysozyme and cytochrome c when compared to poly-L-SULA and poly-SUS.     

Separation of acetylcholinesterase inhibitors using polymeric surfactants in polyelectrolyte multilayer coatings

The main objective of this study is the use of polymeric surfactants in polyelectrolyte multilayer (PEM) coatings for the separation of the pharmaceutical substances acetylcholinesterase inhibitors (AChEIs). AChEIs are used for the treatment of Alzheimer's Disease and Myasthenia Gravis. In the open-tubular capillary electrochromatography (OT-CEC) mode, the PEM coating is evaluated using nine AChEIs. Optimal conditions are established by altering several experimental parameters such as the pH of the background electrolyte (BGE), the anionic polymer for the PEM coating, the concentration of NaCl, which is used as an additive in the polymer deposition solutions, the number of bilayers, the deposition time, and the concentration of the polymeric surfactant. 25 mM NaH(2)PO(4).H(2)Ο and 25 mM Na(2)HPO(4) at pH 7 is used as BGE. Two bilayers of poly(diallyl dimethyl ammonium chloride) and poly(sodium N-undecanoyl L-leucinate) provide a baseline separation of all nine analytes in less than 4.5 min. Run-to-run reproducibility studies are also performed, and the relative standard deviation values of the migration times of the nine-analyte peaks are less than 2%. In addition, day-to-day, week-to-week and capillary-to-capillary reproducibilities are evaluated, and the relative standard deviation values of the electroosmotic flow are less than 2%. Finally, using the PEM coating approach, we were able to perform more than 150 runs in the same column. Neither the addition of the polymeric surfactant to the mobile phase, nor the reconstruction of the coating was necessary.     

Polymeric ionic liquid as a dynamic coating additive for separation of basic proteins by capillary electrophoresis

A simple and economical capillary electrophoresis method has been developed for the analysis of four model basic proteins by employing a polymeric ionic liquid (PIL), poly(1-vinyl-3-butylimidazolium) bromide, as the dynamic coating additive. When a small amount of PIL was present in the background electrolyte, a cationic coating on the inner surface of fused-silica capillary was established. These PIL modified capillaries not only generated a stable reversed electroosmotic flow, but also effectively eliminated the wall adsorption of proteins. Several important parameters such as the PIL concentration in the background electrolyte, pH values and concentrations of the background electrolyte were optimized to improve the separation of basic proteins. Consequently, under the optimum conditions, a satisfied separation of basic proteins with peak efficiencies ranging from 247,000 to 540,000 (plates m⁻¹) had been accomplished within 11 min. The run-to-run RSDs (n = 3) of the migration times for the four basic proteins were all less than 0.37%.     

Separation of cationic polymer particles and characterization of avidin-immobilized particles by capillary electrophoresis

Cationic polymer microparticles have received much attention especially in the field of biotechnology, such that their analysis and separation have become important. So far, the separation of cationic polymer particles with different size using CE has not been achieved and the cationic particles migrated as if they are negatively charged, probably due to electrostatic interaction between capillary wall and cationic polymer particles. In this paper, the separation of cationic polymer microparticles by CE was investigated in detail. The separation of cationic particles with different size was achieved in CE by taking into account the interaction between sample particles and the inner surface of capillaries. By employing a poly(vinyl alcohol)-coated capillary, a better size separation of amine-modified latex particles was obtained compared to a Polybrene-coated capillary. It was elucidated that the composition, concentration, and pH of the background solution were also important factors in the separation of colloidal particles to avoid the surface adsorption and the characteristic aggregation of polymer particles. Furthermore, the CE analysis was applied to the characterization of cationic protein-immobilized particles.     

Chiral separations using polymeric dipeptide surfactants: effect of number of chiral centers and steric factors.

Two polymeric dipeptide chiral surfactants (PDCSs), poly sodium N-undecanoyl isoleucyl-valinate (SUILV) with three chiral centers and poly sodium N-undecanoyl leucyl-valinate (SULV) with two chiral centers, have been evaluated and compared as chiral pseudo-stationary phases in electrokinetic capillary chromatography. The performance of these surfactants, in terms of enantioselectivity was examined using anionic, cationic and neutral analytes. Analyses of the data suggest that the enantiomeric resolutions of the analytes with these two PDCSs are dependent upon steric factors rather than number of stereogenic centers.     

Effect of coating electrolytes on two-tailed surfactant bilayer coatings in capillary electrophoresis

Surfactants such as dioctadecyldimethylammonium bromide (DODAB) form semi-permanent coatings that effectively prevent adsorption of cationic proteins onto the fused silica capillary in capillary electrophoresis (CE). The bilayer coating is generated by flushing the capillary with a 0.1 mM surfactant solution. However, formation of the bilayer is strongly dependent on the coating electrolyte. The effect of counter-ions, electrolyte concentrations and buffer co-ions were monitored based on: the separation of basic model proteins; the adsorption kinetics of DODA⁺ onto fused silica; and dynamic light scattering (DLS) to determine vesicle size. Low concentrations (≤10.0 mM) and/or weakly associating buffers such as phosphate (pH 3.0), acetate (pH 4.0) and chloride should be used for DODAB coating solutions. Dissolving the surfactant in strongly associating electrolyte, such as phosphate at pH 7.0, results in poor coating of the capillary surface. Effective cationic bilayer coatings are formed if the buffer conditions favor formation of vesicles with diameters < 300 nm. Monitoring turbidity at 400 nm provides a convenient means of verifying vesicle diameter variation of <5 nm; that is, that the coating solution is effective.     

Use of coated capillaries for the electrophoretic separation of stereoisomers of a growth hormone secretagogue

The diastereoisomeric separation of peptidomimetics of hexarelin, a strong growth hormone secretagogue, in CE has been studied. Highly sulfated‐γ‐CD was found to be an appropriate selector for the separation of the stereoisomers. However, non‐repeatable analyses were obtained on bare fused silica capillary due to the progressive adsorption of the analytes on the capillary wall. Two types of polyelectrolyte coating agents were tested to prevent this phenomenon. Coating with neutral polyethylene oxide was found to be efficient but resulted in a very long analysis time (about 40 min). Coating with cationic poly(diallyldimethylammonium) chloride was found both to prevent analyte adsorption, reduce analysis time and alter separation selectivity. EOF measurement revealed that the highly sulfated‐γ‐CDs were strongly adsorbed on the poly(diallyldimethylammonium) chloride coating surface yielding a stable strong cathodic EOF, which considerably reduced analysis time (about 12 min). Very good repeatability of analysis was obtained (RSD_{migration time}<1%).     

Positive cooperative mechanistic binding of proteins at low concentrations: a comparison of poly (sodium N-undecanoyl sulfate) and sodium dodecyl sulfate

The interactions of the negatively charged achiral molecular micelle, poly (sodium N-undecanoyl sulfate) (poly-SUS), with four different proteins using intrinsic and extrinsic fluorescence spectroscopic probes, are studied. A comparison of poly-SUS with the conventional surfactant, sodium dodecyl sulfate (SDS), and the monomeric species, SUS, is also reported. In this work, we observed that poly-SUS preferentially binds to acidic proteins, exhibiting positive cooperativity at concentrations less than 1 mM for all proteins studied. Moreover, it appears that the hydrophobic microdomain formed through polymerization of the terminal vinyl group of the monomer, SUS, is largely responsible for the superior binding capacity of poly-SUS. From these results, we conclude that the interactions of poly-SUS with the acidic proteins are predominantly hydrophobic and postulate that poly-SUS would produce superior interactions relative to SDS at low concentrations in polyacrylamide gel electrophoresis (PAGE). As predicted, use of poly-SUS allowed separation of the His-tagged tumor suppressor protein, p53, at sample buffer concentrations as low as 0.08% w/v (2.9 mM), which is 24 times lower than required for SDS in the standard reducing PAGE protocol. This work highlights the use of poly-SUS as an effective surfactant in 1D biochemical analysis.     

Ultra-high-stability,pH-resistant sol–gel titania poly(tetrahydrofuran) coating for capillary microextraction on-line coupled to high-performance liquid chromatography

A sol–gel titania poly(tetrahydrofuran) (poly-THF) coating was developed for capillary microextraction hyphenated on-line with high-performance liquid chromatography (HPLC). Poly-THF was covalently bonded to the sol–gel titania network which, in turn, became chemically anchored to the inner surface of a 0.25 mm I.D. fused silica capillary. For sample preconcentration, a 38-cm segment of the sol–gel titania poly-THF coated capillary was installed on an HPLC injection port as a sampling loop. Aqueous samples containing a variety of analytes were passed through the capillary and, during this process, the analytes were extracted by the sol–gel titania poly-THF coating on the inner surface of the capillary. Using isocratic and gradient elution with acetonitrile/water mobile phases, the extracted analytes were desorbed into the on-line coupled HPLC column for separation and UV detection. The sol–gel titania poly-THF coating was especially efficient in extracting polar analytes, such as underivatized phenols, alcohols, amines, and aromatic carboxylic acids. In addition, this coating was capable of extracting moderately polar and nonpolar analytes, such as ketones and polycyclic aromatic hydrocarbons. The sol–gel titania poly-THF coated capillary was also able to extract polypeptides at pH values near their respective isoelectric points. Extraction of these compounds can be important for environmental and biomedical applications. The observed extraction behavior can be attributed to the polar and nonpolar moieties in the poly-THF structure. This coating was found to be stable under extremely low and high pH conditions—even after 18 h of exposure to 1 M HCl (pH ≈0.0) and 1 M NaOH (pH ≈14.0).     

Capillary zone electrophoretic separation of neutral species of chloro-s-triazines in the presence of cationic surfactant monomers

Chloro-s-triazines are difficult to separate by capillary zone electrophoresis (CZE), due to their low pKa values. However, these analytes can be effectively separated by CZE in the presence of cationic surfactant monomers, such as tetradecylammonium bromide (TTAB) and dodecyltrimethylammonium bromide (DTAB). The separation mechanism based on a 1:1 binding of analytes to cationic surfactant monomers is proposed. The binding constants of chloro-s-triazines to cationic surfactant monomers are estimated. The results show that the strength of the interactions of these analytes with TTAB monomers is considerably strong, whereas that of the corresponding analyte with DTAB monomers is about 12- to 14-fold weaker. A linear correlation of binding constants with log P(ow) (the logarithm of the partition coefficient of analytes between 1-octanol and aqueous phases) indicates that the migration order of these chloro-s-triazines depends primarily on their hydrophobicity. Moreover, the skewed peaks of chloro-s-triazines observed may reveal the occurrence of adsolubilization of these analytes in the adsorbed cationic surfactant layer on the capillary surface.     

Investigation of the stability of polyelectrolyte multilayer coatings in open-tubular capillary electrochromatography using laser scanning confocal microscopy

A simple polyelectrolyte multilayer (PEM) coating procedure was used for the development of stable modified capillaries. PEM coatings were constructed in fused-silica capillaries using alternating rinses of cationic and anionic polyelectrolytes. The multilayer coatings investigated in this study consisted of two and twenty layer pairs, or bilayers. A bilayer is one layer of a cationic polymer and one layer of an anionic polymer. Poly(diallyldimethylammonium chloride) was used as the cationic polymer, and the polymeric surfactant poly(sodium N-undecanoyl-L-leucylvalinate) was used as the anionic polymer. Previous studies for both chiral and achiral separations have shown that PEM-coated capillaries have excellent reproducibilities, remarkable endurance, and strong stabilities against extreme pH values when used in open-tubular capillary electrochromatography (OT-CEC). In this study, the stability of the coatings was further investigated after exposure to 0.1 M and 1.0 M NaOH. Structural changes of these coatings were monitored using laser scanning confocal microscopy (LSCM) after flushing the capillaries with NaOH. This technique allowed observation of the degradation of the coatings. Observations are discussed in terms of separations using OT-CEC. Electropherograms obtained from the chiral separation of 1,1'-binaphthyl-2,2'-dihydrogenphosphate in OT-CEC showed a decrease in selectivity and an increase in electroosmotic mobility after long exposure to NaOH. The ability to recover the capillaries by exposure to NaOH was also demonstrated. Measurements of electroosmotic mobility and selectivity showed that 2-bilayer and 20-bilayer PEM coatings could be completely removed from the capillary surface after approximately 3.5 and 9.5 h, respectively, of continuous exposure to 1 M NaOH.     

CE as orthogonal technique to HPLC for alprazolam degradation product identification

The control of degradation products is currently a critical issue to the pharmaceutical industry. A degradation product that appeared in alprazolam tablets during their stability assay, 7-chloro-1-methyl-5-phenyl-[1,2,4]triazolo[4,3-a]quinolin-4-amine, also named triazolaminoquinoline, was tested as possible candidate in the HPLC method employed for the study. The impurity showed the same retention time and spectra as the degradation product; but as all these compounds are very closely related, a confirmation with an independent technique was necessary, and CE was chosen for that purpose. Problems related to the adsorption of the analytes to the negatively charged silica surface were solved by employing a new polymeric capillary coating consisting of poly(3-aminopropylmethylsiloxane). The polymer provided EOF towards the anode, and the two compounds were separated in less than 8 min in a 60 cm total-length capillary, 75 microm id capillary with a BGE containing 50 mM phosphate buffer at pH 2.0 with 20% ACN. When the sample containing the degradation product was injected, the presence of triazolaminoquinoline was confirmed.     

Evaluation of poly([2‐(acryloyloxy)ethyl]trimethylammonium chloride) cationic polymer capillary coating for capillary electrophoresis and electrokinetic chromatography separations

Capillary electrophoresis and electrokinetic chromatography are typically carried out in unmodified fused‐silica capillaries under conditions that result in a strong negative zeta potential at the capillary wall and a robust cathodic electroosmotic flow. Modification of the capillary wall to reverse the zeta potential and mask silanol sites can improve separation performance by reducing or eliminating analyte adsorption, and is essential when conducting electrokinetic chromatography separations with cationic latex nanoparticle pseudo‐stationary phases. Semipermanent modification of the capillary walls by coating with cationic polymers has proven to be facile and effective. In this study, poly([2‐(acryloyloxy)ethyl]trimethylammonium chloride) polymers were synthesized by reversible addition‐fragmentation chain transfer polymerization and used as physically adsorbed semipermanent coatings for capillary electrophoresis and electrokinetic chromatography separations. An initial synthesis of poly([2‐(acryloyloxy)ethyl]trimethylammonium chloride) polymer coating produced strong and stable anodic electroosmotic flow of –5.7 to –5.4 × 10⁻⁴ cm²/V⋅s over the pH range of 4–7. Significant differences in the magnitude of the electroosmotic flow and effectiveness were observed between synthetic batches, however. For electrokinetic chromatography separations, the best performing batches of poly([2‐(acryloyloxy)ethyl]trimethylammonium chloride) polymer performed as well as the commercially available cationic polymer polyethyleneimine, whereas polydiallylammonium chloride and hexadimethrine bromide did not perform well.     

Cationic starch derivatives as dynamic coating additives for protein analysis in capillary electrophoresis

Positively charged starch derivatives were used to modify the inner surface of fused-silica capillaries by addition to running buffer, which were subsequently employed in capillary electrophoresis (CE). Capillaries coated with the cationic starch derivatives were shown to generate a stable, reversed electroosmotic flow (EOF) in the investigated pH range of 3-9. The presented coating procedure was fast, based on a simple rinsing protocol where the polymer created a physically adsorbed, cationic polymer layer. Among the additives studied, a quaternary ammonium starch derivative showed a fast EOF mobility and effectively suppressed the adsorption of proteins. The intra- and inter-day reproducibility of the coating referring to the EOF mobility were satisfactory with relative standard deviation (RSD) of 0.27 and 1.67%, respectively. The coating enabled separation of some protein mixtures including basic proteins within l3 min with efficiencies up to 280,000 plates/m. In addition, this cationic starch derivative possessed a good solubility (about 100mg/mL), and it does not significantly contribute to the background adsorption in the UV region of 190-400 nm.     

A semipermanent coating for preventing protein adsorption at physiological pH in kinetic capillary electrophoresis

Protein adsorption to the inner capillary wall hinders the use of kinetic capillary electrophoresis (KCE) when studying noncovalent protein-ligand interactions. Permanent and dynamic capillary coatings have been previously reported to alleviate much of the problems associated with protein adsorption. The characteristic limitations associated with permanent and dynamic coatings motivated us to look at a third type of coating - semipermanent. Here, we demonstrate that a semipermanent capillary coating, designed by Lucy and co-workers, comprised of dioctadecyldimethylammonium bromide (DODAB) and polyoxyethylene (POE) stearate, greatly reduces protein adsorption at physiological pH - a necessary requirement for KCE. The coating (i) does not inhibit protein-DNA complex formation, (ii) prevents the adsorption of the analytes, and (iii) supports an electoosmotic flow required for many applications of KCE. The coating was tested in three physiological buffers using a well-known DNA aptamer and four proteins that severely bind to bare silica capillaries as standards. For every protein, a condition was found under which the semipermanent coating effectively suppresses protein adhesion. While no coating can completely prevent the adsorption of all proteins, our findings suggest that the DODAB/POE stearate coating can have a broad impact on CE at large, as it prevents the absorption of several well studied, highly adhesive proteins at physiological pH.     

Graft copolymer composed of cationic backbone and bottle brush-like side chains as a physically adsorbed coating for protein separation by capillary electrophoresis

To stabilize electroosmotic flow (EOF) and suppress protein adsorption onto the silica capillary inner wall, a cationic hydroxyethylcellulose-graft-poly (poly(ethylene glycol) methyl ether methacrylate) (cat-HEC-g-PPEGMA) graft copolymer composed of cationic backbone and bottle brush-like side chains was synthesized for the first time and used as a novel physically adsorbed coating for protein separation by capillary electrophoresis. Reversed (anodal) and very stable EOF was obtained in cat-HEC-g-PPEGMA-coated capillary at pH 2.2-7.8. The effects of degree of cationization, PEGMA grafting ratio, PEGMA molecular mass, and buffer pH on the separation of basic proteins were investigated. A systematic comparative study of protein separation in bare and HEC-coated capillaries and in cat-HEC-g-PPEGMA-coated capillary was also performed. The basic proteins can be well separated in cat-HEC-g-PPEGMA-coated capillary over the pH range of 2.8-6.8 with good repeatability and high separation efficiency, because the coating combines good protein-resistant property of bottle brush-like PPEGMA side chains with excellent coating ability of cat-HEC backbone. Besides its success in separation of basic proteins, the cat-HEC-g-PPEGMA coating was also superior in the fast separation of other protein samples, such as protein mixture, egg white, and saliva, which indicates that it is a promising coating for further proteomics analysis.     

双动态吸附毛细管电色谱的手性分离——采用阳离子表面活性剂和阴离子手性选择剂作为假固定相

建立了以十六烷基三甲基溴化铵或1,5－二甲基－1,5－二氮杂十一烷亚甲基聚N－甲溴化物为阳离子表面活性剂,并以磺丁基β－环糊精为手性选择剂的双动态吸附毛细管电色谱。以碱性的丙比胺和酸性的华法林作为拆分对象,考察了双动态吸附毛细管电色谱的手性分离行为,以及动态吸附柱的重复性。在双动态吸附毛细管电色谱条件下,丙比胺和华法林的手性分离度较大,丙比胺的分离度可达3．21,丙比胺连续进样10次,迁移时间的相对标准偏差小于1．0％。     

Polymeric sulfated surfactants with varied hydrocarbon tail: I. Synthesis, characterization, and application in micellar electrokinetic chromatography

The influence of surfactant hydrocarbon tail on the solute/pseudostationary phase interactions was examined. Four anionic sulfated surfactants with 8-, 9-, 10-, and 11-carbon chains having a polymerizable double bond at the end of the hydrocarbon chain were synthesized and characterized before and after polymerization. The critical micelle concentration (CMC), polarity, and aggregation number of the four sodium alkenyl sulfate (SAIS) surfactants were determined using fluorescence spectroscopy. The partial specific volume of the polymeric SAIS (poly-SAIS) surfactants was estimated by density measurements and capillary electrophoresis (CE) was employed for determination of methylene selectivity as well as for elution window. The CMC of the monomers of SAIS surfactants decrease with increase in chain length and correlated well when fluorescence method was compared to CE. The physicochemical properties (partial specific volume, methylene selectivity, electrophoretic mobility, and elution window) increased with an increase in chain length. However, no direct relationship was found between the aggregation number and the length of hydrophobic tail of poly-SAIS surfactants. These polymeric surfactants were then used as pseudostationary phases in micellar electrokinetic chromatography (MEKC) to study the retention behavior and selectivity factor of 36 benzene derivatives with different chemical characteristics. Although variation in chain length of the polymeric surfactants significantly affects the retention of nonhydrogen bonding (NHB) benzene derivatives, these effects were less pronounced for hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) benzene derivatives. Therefore, hydrophobicity of poly-SAIS surfactants was found to be a major driving force for retention of NHB derivatives. However, for several benzene derivatives (NHB, HBA, and HBD) significantly higher selectivity factor was observed with longest chain polymeric surfactant (e.g., poly(sodium 10-undecenyl sulfate), poly-SUS) compared to shorter chain polymeric surfactant (e.g., poly(sodium 7-octenyl sulfate), poly-SOcS). In addition, the effect of the surfactant hydrophobic chain was also found to have some impact on migration order of NHB, HBA, and HBD benzene derivatives.