1
|
Poole CF, Atapattu SN, Poole SK, Bell AK. Determination of solute descriptors by chromatographic methods. Anal Chim Acta 2009; 652:32-53. [DOI: 10.1016/j.aca.2009.04.038] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 04/25/2009] [Accepted: 04/28/2009] [Indexed: 11/24/2022]
|
2
|
Quantitative structure–retention (property) relationships in micellar electrokinetic chromatography. J Chromatogr A 2008; 1182:1-24. [DOI: 10.1016/j.chroma.2007.12.080] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2007] [Revised: 11/24/2007] [Accepted: 12/31/2007] [Indexed: 10/22/2022]
|
3
|
Van Biesen G, Bottaro CS. Linear solvation energy relationships of anionic dimeric surfactants in micellar electrokinetic chromatography. J Chromatogr A 2008; 1180:171-8. [DOI: 10.1016/j.chroma.2007.11.059] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 11/04/2007] [Accepted: 11/21/2007] [Indexed: 10/22/2022]
|
4
|
Fuguet E, Ràfols C, Bosch E, Abraham MH, Rosés M. Selectivity of single, mixed, and modified pseudostationary phases in electrokinetic chromatography. Electrophoresis 2006; 27:1900-14. [PMID: 16607607 DOI: 10.1002/elps.200500464] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The selectivity of a compilation of single, mixed, and modified EKC pseudostationary phases, described in the literature and characterized through the solvation parameter model, is analyzed. Not only have micellar systems of different nature been included but also microemulsions, polymeric, and liposomial phases. In order to compare the systems, a principal component analysis of the coefficients of the solvation equation is performed. From this analysis, direct information of the system properties, differences in selectivity, as well as evidence of lack of accuracy in some system characterizations are obtained. These results become a very useful tool to perform separations with mixtures of surfactants, since it is possible to know which mixtures will provide a greater selectivity variation by changing only the composition of the pseudostationary phases. Furthermore, the variation of the selectivity of some mixtures, as well as the effect of the addition of organic solvents on selectivity, is also discussed.
Collapse
Affiliation(s)
- Elisabet Fuguet
- Departament de Química Analítica, Universitat de Barcelona, Barcelona, Spain
| | | | | | | | | |
Collapse
|
5
|
Shamsi SA, Iqbal R, Akbay C. Glycine-based polymeric surfactants with varied polar head group: II. chemical selectivity in micellar electrokinetic chromatography using linear solvation energy relationships. Electrophoresis 2005; 26:4138-52. [PMID: 16252318 DOI: 10.1002/elps.200500363] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A series of four acyl and four alkenoxy glycinates (i.e., mono-, di-, tri-, and tetraderivatives of polysodium N-undecenoyl glycinate (poly-SUGs) as well as polysodium N-undecenoxy carbonyl glycinates (poly-SUCGs)) were compared for simultaneous separation of nonhydrogen bonding (NHB), hydrogen-bond acceptor (HBA), and hydrogen-bond donor (HBD) solutes. An increase in the number of glycine units in the polar head group of polymeric surfactant decreases both the retention and the migration window of all solutes with some changes in separation selectivity. The poly(sodium N-undecenoxy carbonyl-glycinate) (poly-SUCG1) with one glycine unit was the least polar surfactant and has the lowest phase ratio, but this monoglycinate surfactant provided the best simultaneous separation of 10-NHBs and 8-HBAs. On the other hand, 9-HBDs were well separated using any of the six mono-, di-, and triglycinate surfactants compared to the two tetraglycinates. Linear solvation energy relationships (LSERs) and separation of the geometrical isomers studies were also performed to further envisage the selectivity differences. From LSER studies, the phase ratio and hydrogen-bond-donating strength of the poly-SUG series of surfactant were found to increase with an increase in the size of the head group, but no clear trends were observed for poly-SUCG surfactants. The cohesiveness for all poly-SUG and poly-SUCG was positive, but the values were generally lower (with exception of the poly(sodium N-undecenoyl glycyl-glycyl-glycinate)) at a higher number of glycine units. Finally, the poly(sodium N-undecenoyl glycinate) and poly-SUCG1 were found to be the two best polymeric surfactants as they provided relatively higher shape selectivity for separation of two of the three sets of geometrical isomers.
Collapse
Affiliation(s)
- Shahab A Shamsi
- Department of Chemistry, Center of Biotechnology and Drug Design Georgia State University, Atlanta, GA 30302-4098, USA.
| | | | | |
Collapse
|
6
|
Poole SK, Poole CF. Separation methods for estimating octanol-water partition coefficients. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 797:3-19. [PMID: 14630140 DOI: 10.1016/j.jchromb.2003.08.032] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Separation methods for the indirect estimation of the octanol-water partition coefficient (logP) are reviewed with an emphasis on high throughput methods with a wide application range. The solvation parameter model is used to identify suitable separation systems for estimating logP in an efficient manner that negates the need for empirical trial and error experiments. With a few exceptions, systems based on reversed-phase chromatography employing chemically bonded phases are shown to be unsuitable for estimating logP for compounds of diverse structure. This is because the fundamental properties responsible for chromatographic retention tend to be different to those responsible for partition between octanol and water, especially the contribution from hydrogen bonding interactions. On the other hand, retention in several micellar and microemulsion electrokinetic chromatography systems is shown to be highly correlated with the octanol-water partition coefficient. These systems are suitable for the rapid, high throughput determination of logP for neutral, weakly acidic, and weakly basic compounds. For compounds with a permanent charge, electrophoretic migration and electrostatic interactions with the stationary phase results in inaccurate estimation of partition coefficients. The experimental determination of solute descriptors offers an alternative approach for estimating logP, and other biopartitioning properties. A distinct advantage of this approach is that once the solute descriptors are known, solute properties can be estimated for any distribution or transport system for which a solvation parameter model has been established.
Collapse
Affiliation(s)
- Salwa K Poole
- Discovery Technologies, Pfizer Global Research and Development, Ann Arbor Laboratories, 2800 Plymouth Road, Ann Arbor, MI 48105USA.
| | | |
Collapse
|
7
|
Abstract
The determination of the velocities of the mobile and the pseudostationary phases (the migration (time) window) is mandatory for the determination of physicochemical properties by electrokinetic chromatography (EKC). This review offers a detailed discussion on the definition, the importance, the determination and the regulation of the migration (time) window in EKC. An overview on the theoretical treatment of chromatographic processes in EKC is given defining EKC in comparison to the term capillary electrophoresis. Methods to determine and influence the migration window are discussed with emphasis on measures that have been taken to modify the electroosmotic flow velocity. Pseudostationary phases (or separation carriers) that are taken into consideration are anionic and cationic micelles, mixed micelles, microdroplets (microemulsions), polymeric pseudostationary phases and dendrimers.
Collapse
Affiliation(s)
- Ute Pyell
- Philipps- Universität Marburg, Fachbereich Chemie, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.
| |
Collapse
|
8
|
Monton MRN, Otsuka K, Terabe S. On-line sample preconcentration in micellar electrokinetic chromatography by sweeping with anionic-zwitterionic mixed micelles. J Chromatogr A 2003; 985:435-45. [PMID: 12580512 DOI: 10.1016/s0021-9673(02)01654-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
On-line preconcentration by sweeping in micellar electrokinetic chromatography using mixed micelles of sodium dodecyl sulfate (SDS)-SB-12 is presented. Because of their large micelle radius, they permit increased partitioning of hydrophobic analytes into the core. In addition, they also possess lower negative surface charge relative to pure SDS micelles so anionic analytes can be retained better due to decreased electrostatic repulsion. As the efficiency of sweeping is predicated on the magnitude of retention factors, these advantages translated to better focusing. As much as a 370-fold improvement in detector response, in terms of peak height, was obtained for some neutral steroids, while about a 360-fold improvement was obtained for some phenol derivatives, which were previously not amenable to sweeping by pure SDS micelles.
Collapse
Affiliation(s)
- Maria Rowena N Monton
- Graduate School of Science, Himeji Institute of Technology, Kamigori, Hyogo 678-1297, Japan.
| | | | | |
Collapse
|
9
|
Fuguet E, Ràfols C, Torres-Lapasió JR, García-Alvarez-Coque MC, Bosch E, Rosés M. Solute-solvent interactions in micellar electrokinetic chromatography. 6. Optimization of the selectivity of lithium dodecyl sulfate-lithium perfluorooctanesulfonate mixed micellar buffers. Anal Chem 2002; 74:4447-55. [PMID: 12236354 DOI: 10.1021/ac0201530] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The optimization of the composition of mixed surfactants used as micellar electrokinetic chromatography (MEKC) pseudostationary phases is proposed as an effective method for the separation of complex mixtures of analytes. The solvation parameter model is used to select two surfactants (lithium dodecyl sulfate, LDS, and lithium perfluorooctanesulfonate, LPFOS) with contrasting solvation properties. Combination of these two surfactants allows variations of the solvation properties of MEKC pseudostationary phase along a wide range. Thus, the convenient variation of the proportion of both surfactants allows an effective control of the selectivity in such systems. An algorithm that predicts the overall resolution of a given mixture of compounds is described and applied to optimize the composition of the mixed surfactant for the separation of the mixture. The algorithm is based on the calculation of peak purities on simulated chromatograms as a function of the composition of the mixed LDS/LPFOS micellar buffer from data at several micellar buffer compositions. Successful separations were achieved for mixtures containing up to 20 compounds, in less than 12 min.
Collapse
Affiliation(s)
- Elisabet Fuguet
- Departament de Química Analítica, Universitat de Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
10
|
Abstract
The solvation parameter model is a useful tool for delineating the contribution of defined intermolecular interactions to retention of neutral molecules in separation systems based on a solute equilibrium between a gas, liquid or fluid mobile phase and a liquid or solid stationary phase. The free energy for this process is decomposed into contributions for cavity formation and the set up of intermolecular interactions identified as dispersion, electron lone pair, dipole-type and hydrogen bonding. The relative contribution of these interactions is indicated by a series of system constants determined by the difference of the defined interaction in the two phases. The interpretation of these system constants as a function of experimental factors that affect retention in the chromatographic system provides the connection between relative retention (selectivity) and the control variables for the separation system. To aid in the understanding of these processes we perform an analysis of system constants for gas chromatography, liquid chromatography, supercritical fluid chromatography and micellar electrokinetic chromatography as a function of different experimental variables as a step towards gaining a theoretical understanding of selectivity optimization for method development.
Collapse
Affiliation(s)
- Colin F Poole
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
| | | |
Collapse
|
11
|
Fuguet E, Ràfols C, Bosch E, Abraham MH, Rosés M. Solute-solvent interactions in micellar electrokinetic chromatography. III. Characterization of the selectivity of micellar electrokinetic chromatography systems. J Chromatogr A 2002; 942:237-48. [PMID: 11822389 DOI: 10.1016/s0021-9673(01)01383-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several micellar electrokinetic chromatography (MEKC) systems (sodium dodecyl sulfate, lithium dodecyl sulfate, lithium perfluorooctanesulfonate, sodium cholate, sodium deoxycholate, tetradecyltrimethylammonium bromide and hexadecyltrimethylammonium bromide) have been characterized by means of the solvation parameter model. It has been observed that the coefficients of the correlation equations depend strongly on the particular set of compounds analyzed. Principal component analysis has been used to characterize the 2975 compounds with available solute descriptors and to select an appropriate subset of compounds to be analyzed by MEKC. With this set of compounds, the MEKC systems have been characterized. Principal component analysis has also been used to show the similarities and differences between the properties of the surfactants characterized by MEKC.
Collapse
Affiliation(s)
- Elisabet Fuguet
- Department de Química Analítica, Universitat de Barcelona, Spain
| | | | | | | | | |
Collapse
|
12
|
Shi W, Peterson DS, Palmer CP. Effect of pendant chain lengths and backbone functionalities on the chemical selectivity of sulfonated amphiphilic copolymers as pseudo-stationary phases in electrokinetic chromatography. J Chromatogr A 2001; 924:123-35. [PMID: 11521859 DOI: 10.1016/s0021-9673(01)00760-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amphiphilic copolymers of AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid) and hydrophobic monomers with various chemical structures were synthesized, characterized and used as novel electrokinetic chromatography polymeric pseudo-stationary phases, showing significant chemical selectivity differences from that of the conventional monomeric pseudo-stationary phase, sodium lauryl sulphate. Copolymers of AMPS and methacrylates with different pendant chain lengths (C8, C12 and C18) were investigated and no significant difference in chemical selectivity was observed among them. However, the spacer bonding chemistry was shown to contribute to significant chemical selectivity difference, e.g. poly(AMPS-lauryl methacrylate) showed different chemical selectivity from poly(AMPS-lauryl methacrylamide). Linear solvation energy relationship analysis of 20 solutes by eight different polymeric pseudo-stationary phases was employed to investigate the solute molecule structural contributions to the retention. Hydrogen-bonding properties (described by system constants b and a) of poly(AMPS-alkyl methacrylamide) were found stronger than those of poly(AMPS-alkyl methacrylate).
Collapse
Affiliation(s)
- W Shi
- Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro 87801, USA
| | | | | |
Collapse
|
13
|
Fujimoto C. Application of linear solvation energy relationships to polymeric pseudostationary phases in micellar electrokinetic chromatography. Electrophoresis 2001; 22:1322-9. [PMID: 11379954 DOI: 10.1002/1522-2683(200105)22:7<1322::aid-elps1322>3.0.co;2-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Polymerized sodium 11-acrylamidoundecanoate (poly(Na 11-AAU)) was used as a pseudostationary phase (PSP) for micellar electrokinetic chromatography to separate uncharged compounds. The polymer PSP showed signifcantly different solute migration behaviors from conventional micelles including sodium dodecyl sulfate and poly (sodium 10-undecylenate), giving high separation efficiencies (>200000 theoretical plates/m). Linear solvation energy relationships were used to evaluate and characterize the chemical interactions that influence the retention behavior in the poly (Na 11-AAU) micellar system. It was found that the solute volume and solute hydrogen bond basicity mainly influenced the retention. The characteristic feature of the poly (Na 11-AAU) micellar system is that the micelle has a significantly higher capacity for dipole-dipole and dipole-induced dipole interactions as well as a slightly higher capacity for electron pair interactions than the aqueous phase. Due to its unique selectivity, the poly(Na 11-AAU) micellar system would become an attractive new option for selectivity optimization on methods development.
Collapse
Affiliation(s)
- C Fujimoto
- Department of Chemistry, Hamamatsu University School of Medicine, Japan.
| |
Collapse
|
14
|
Fuguet E, Ràfols C, Bosch E, Rosés M, Abraham MH. Solute-solvent interactions in micellar electrokinetic chromatography. Selectivity of lithium dodecyl sulfate-lithium perfluorooctanesulfonate mixed-micellar buffers. J Chromatogr A 2001; 907:257-65. [PMID: 11217033 DOI: 10.1016/s0021-9673(00)01038-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The solvation parameter model has been applied to the characterization of micellar electrokinetic chromatographic (MEKC) systems with mixtures of lithium dodecyl sulfate and lithium perfluorooctanesulfonate as surfactant. The variation in MEKC surfactant composition results in changes in the coefficients of the correlation equation, which in turns leads to information on solute-solvent and solute-micelle interactions. Lithium perfluorooctanesulfonate is more dipolar and hydrogen bond acidic but less polarizable and hydrogen bond basic than lithium dodecyl sulfate. Therefore mixtures of lithium dodecyl sulfate and lithium perfluorooctanesulfonate cover a very wide range of polarity and hydrogen bond properties, which in turn results in important selectivity changes for analytes with different solute properties.
Collapse
Affiliation(s)
- E Fuguet
- Department de Química Analítica, Universitat de Barcelona, Spain
| | | | | | | | | |
Collapse
|
15
|
Abraham MH, Gola JM, Kumarsingh R, Cometto-Muniz JE, Cain WS. Connection between chromatographic data and biological data. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2000; 745:103-15. [PMID: 10997706 DOI: 10.1016/s0378-4347(00)00130-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
There are no previous references to the direct use of GLC data in the correlation of biological processes, but we show that GLC retention data can be used in the correlation of several such processes involving gaseous solutes. There are a number of reports of RP-HPLC and MEKC data being used in the correlation of biological processes, but they are mostly restricted as to the number and type of solute studied. We show that if chromatographic data are used to obtain solvation descriptors for solutes, and if these descriptors are then used in the correlation of biological processes, that this indirect connection is a much more powerful and generally applicable method than is the direct connection between chromatographic data and biological data.
Collapse
Affiliation(s)
- M H Abraham
- Department of Chemistry, University College London, UK
| | | | | | | | | |
Collapse
|
16
|
Poole SK, Durham D, Kibbey C. Rapid method for estimating the octanol--water partition coefficient (log P ow) by microemulsion electrokinetic chromatography. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2000; 745:117-26. [PMID: 10997707 DOI: 10.1016/s0378-4347(00)00072-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Several surfactant systems were evaluated based on their system constants determined by the solvation parameter model for the design of a surrogate chromatographic model for the rapid estimation of octanol-water partition coefficient (log Pow) by microemulsion electrokinetic chromatography. The system constant ratios responsible for the log Pow partition system are (nearly) the same as those for the microemulsion system containing sodium dodecyl sulfate (1.4% w/v), butan-1-ol (8% v/v) and heptane (1.2% v/v). Neutral and basic compounds are analyzed using a fused-silica capillary column with a 50 mM sodium phosphate-sodium borate (3:2) buffer at pH 10. Weakly acid compounds require the use of sulfonated silica capillary column and a 50 mM sodium phosphate buffer at pH 3. For 29 varied neutral and weakly basic compounds the average error between log Pow estimated using MEEKC and literature values was +/-0.12 over a log Pow range from 0.3 to 5.8.
Collapse
Affiliation(s)
- S K Poole
- Chemistry Department, Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, MI 48105, USA.
| | | | | |
Collapse
|
17
|
Wall WE, Allen DJ, Denson KD, Love GI, Smith JT. Explorations of alkyl polyols as "class I" organic modifiers to adjust selectivity in micellar electrokinetic capillary chromatography. Electrophoresis 1999; 20:2390-9. [PMID: 10499330 DOI: 10.1002/(sici)1522-2683(19990801)20:12<2390::aid-elps2390>3.0.co;2-h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this study, we investigated a novel series of micelle modifiers useful to alter selectivity in micellar electrokinetic capillary chromatography (MEKC). These modifiers were alkyl polyalcohols, including 1-octanol, 1,2-octanediol, 1,2,3-octanetriol, 1,2-hexanediol, and 1,2-butanediol, which act as class I organic modifiers in that their effects are on the sodium dodecyl sulfate (SDS) micelle rather than the surrounding aqueous phase. This characteristic allows the alkyl polyols to effect resolution when applied at concentrations as low as 20 mM (0.25% v/v) by altering the selectivity observed with SDS without a modifier. The effects of the alkyl polyols on the critical micelle concentration of SDS, electroosmotic flow, and electrophoretic mobility of the SDS micelle are presented. These modifiers had little impact on the migration time window at the concentrations explored. Changes in selectivity induced by the alkyl polyols for a large set of model compounds are presented. Trends indicate that solutes capable of forming hydrogen bonds tend to decrease their interactions with the micellar phase while nonhydrogen bonding solutes increase their interactions upon addition of the modifiers. The solvation parameter model was used to characterize the induced changes in selectivity. This model suggests that even though the modifiers are structurally similar, each produced a unique set of system constants. It was also demonstrated that the addition of alkyl polyols improved the correlation between the partition coefficients of SDS and water to 1-octanol and water. The usefulness of the alkyl polyols was demonstrated by examining their effects on the separation of 11 priority phenols.
Collapse
Affiliation(s)
- W E Wall
- Department of Physical Sciences, Southeastern Oklahoma State University, Durant 74701, USA
| | | | | | | | | |
Collapse
|
18
|
Roberts KP, Lin CH, Jankowiak R, Small GJ. On-line identification of diastereomeric dibenzo[a,l]pyrene diol epoxide-derived deoxyadenosine adducts by capillary electrophoresis-fluorescence line-narrowing and non-line narrowing spectroscopy. J Chromatogr A 1999; 853:159-70. [PMID: 10486722 DOI: 10.1016/s0021-9673(99)00507-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A capillary electrophoretic method for the separation and on-line identification of closely related analytes using low-temperature fluorescence spectroscopy is reported for the eight diastereomeric deoxyadenosine (dA) adducts derived from dibenzo[a,l]pyrene diol epoxide (DB[a,l]PDE). Electrophoretic separation of stereoisomers was accomplished by application of a mixed surfactant buffer [dioctyl sulfosuccinate (DOSS) and Brij-S], which was below the critical micelle concentration (CMC) due to the high concentration (approximately 25%) of organic solvent. Addition of multiple surfactant additives to the separation buffer provided electrophoretic resolution, which was unattainable under single surfactant conditions. It is shown that the CE-separated analyte zones could be identified on-line via low-temperature (4.2 K) fluorescence non-line narrowing and fluorescence line-narrowing (FLN) spectroscopy. In addition, it was determined that in CE buffer trans-syn-,cis-syn- and cis-anti-DB[a,l]PDE-14-N6dA diastereomeric adducts exist mostly with the -dA and DB[a,l]P moiety in an "open"-type conformation while the trans-anti-DB[a,l]PDE-14-N6dA adducts exist in two different conformations whose relative distribution depends on matrix composition. The above conformations have also been revealed by selective laser excitation. Thus, the low-temperature methodology not only provides fingerprint structure via vibrationally resolved 4.2 K fluorescence spectra for adduct identification, but also provides conformational information on the spatial relationship of the carcinogen and dA moiety. These results, taken together with those for DB[a,l]P-DNA adducts formed in standard glasses and mouse epidermis exposed to DB[a,l]P, support our earlier findings that DB[a,l]P-derived adducts exist in different conformations [Jankowiak et al., Chem. Res. Toxicol. 11 (1998) 674]. Therefore, the combination of the separation power of CE and spectral selectivity of low-temperature fluorescence spectroscopy at NLN and FLN conditions provides a powerful methodology which should prove useful for identification of closely related DNA adducts formed at low levels in biological systems.
Collapse
Affiliation(s)
- K P Roberts
- Ames Laboratory-US Department of Energy, Iowa Sate University 50011, USA
| | | | | | | |
Collapse
|
19
|
Rosés M, Ràfols C, Bosch E, Martínez AM, Abraham MH. Solute-solvent interactions in micellar electrokinetic chromatography. Characterization of sodium dodecyl sulfate-Brij 35 micellar systems for quantitative structure-activity relationship modelling. J Chromatogr A 1999; 845:217-26. [PMID: 10399337 DOI: 10.1016/s0021-9673(99)00147-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The solvation parameter model has been applied to the characterization of micellar electrokinetic chromatographic (MEKC) systems with mixtures of sodium dodecyl sulfate and Brij 35 as surfactant. The variation in MEKC surfactant composition results in changes in the coefficients of the correlation equation, which in turns leads to information on solute-solvent and solute-micelle interactions. Since the same solvation model can be used to describe many biological processes, particular MEKC surfactant compositions can be selected that model the solute-solvent interactions of some of these processes. Two different MEKC systems have been selected to model the solute-solvent interactions of two processes of biological interest (octanol-water partition and tadpole narcosis).
Collapse
Affiliation(s)
- M Rosés
- Departament de Química Analítica, Universitat de Barcelona, Spain.
| | | | | | | | | |
Collapse
|
20
|
Affiliation(s)
- Stephen C. Beale
- Department of Chemistry, University of Alabama at Birmingham, 901 South 14th Street, CHEM 277, Birmingham, Alabama 36294
| |
Collapse
|
21
|
Poole CF, Poole SK, Abraham MH. Recommendations for the determination of selectivity in micellar electrokinetic chromatography. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(97)01164-3] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
22
|
|