Influence of solvent properties on separation and detection performance in non-aqueous capillary electrophoresis–mass spectrometry of basic analytes

Steiner, Frank; Hassel, Marc

doi:10.1016/j.chroma.2004.11.043

Cited by 31 publications

(21 citation statements)

References 35 publications

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“…Therefore, these solvents favor the formation of a stable ionization spray especially in sheathless nanoelectrospray MS resulting in strong signals [7]. Despite the fact that only a slight advantage of the organic solvents methanol and ACN compared to water was observed in ESI-MS detection using a sheath-liquid interface [8], the higher separation power for some analytes in NACE is the main reason for the use of nonaqueous solvents in CE.…”

Section: Introductionmentioning

confidence: 98%

Analysis of the lipophilic peptaibol alamethicin by nonaqueous capillary electrophoresis-electrospray ionization-mass spectrometry

Psurek¹,

Neusüß

Pelzing

et al. 2005

Electrophoresis

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The microheterogeneous peptaibol alamethicin F30 isolated from the culture broth of Trichoderma viride was analyzed by nonaqueous CE-electrospray-MS using an IT and a TOF mass analyzer. Compared to aqueous buffers, higher separation selectivity was observed for methanolic BGE allowing the detection of more minor components. The low electrophoretic mobility observed for neutral analytes under nonaqueous conditions may be explained by ion-dipole interactions between the peptide analytes and electrolyte ions. The amino acid sequences of the individual components were derived from MS(n) using the doubly or triply charged pseudomolecular ions as well as characteristic fragments as precursor ions. The exchange of Ala by alpha-aminoisobutyric acid (Aib) which is frequently observed for peptaibols was detected for several components. Additional variations included the exchange of Gln to Glu, and the loss of the C-terminal amino alcohol or of the first six amino acids from the N-terminus with concomitant formation of pyroglutamyl residues. In most cases comigration of the Aib peptaibols with the respective Ala component was observed as the mass difference of 14 Da as the result of the amino acid exchange was not sufficient to translate into an electrophoretic separation under the conditions applied. However, proper selection of the precursor ions allowed the unequivocal analysis of the components. Additional TOF-MS measurements were performed in order to resolve the ammonium adducts from comigrating compounds (i.e., Aib-Ala exchange) and to confirm the amino acid composition of the individual components. Except for neutral compounds migrating close to the EOF the mass accuracy was better than 4 ppm for the doubly charged pseudomolecular ions and better than 2 ppm for triply charged ions.

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Section: Introductionmentioning

confidence: 98%

Analysis of the lipophilic peptaibol alamethicin by nonaqueous capillary electrophoresis-electrospray ionization-mass spectrometry

Psurek¹,

Neusüß

Pelzing

et al. 2005

Electrophoresis

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“…In some cases the membrane of the CWE was formed in situ by applying phenylene vinylene oligomer [17] or polypyrrole polymer [17] directly to the surface of the electrode, which shifted the LODs for acidic solutes in CE systems to 1.0610 -6 M. However, the use and characteristics of potentiometric detection in non-aqueous CE systems, which are beneficial in the separation of hydrophobic basic compounds and acidic drugs [25,26], still appear especially challenging. When buffered organic solvents, e. g. acetonitrile or alcohols, were employed as the components of single or binary BGEs, various disturbances could be observed in the detection of catecholamines and beta-blockers by UV absorbance and mass spectrometry [26,27]. This directed attention to potentiometry as an effective and simple remedy in such situations.…”

Section: Introductionmentioning

confidence: 99%

Hydrophobicity‐aided potentiometric detection of catecholamines, beta‐agonists, and beta‐blockers in a mixed‐solvent capillary electrophoresis system

Bazylak¹,

Monge

Everaert

et al. 2008

J of Separation Science

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A series of cationic drug-like substances with distinct basicity, hydrogen-bonding ability, and hydrophobicity, including three catecholamines, two beta-agonists, and thirteen beta-blockers, was successfully detected in a capillary electrophoresis system using an end-capillary coupled potentiometric sensor consisting of a PVC-based liquid membrane deposited directly on a 100 mum diameter copper rod. The electrophoretic separation was performed on a 72 cm x 75 microm id uncoated fused-silica capillary with an acidic background electrolyte containing phosphoric acid in a water-acetonitrile mixture, pH* 2.8. Samples were injected electrokinetically at 5.0 kV for 10 s and a running voltage of 19.5 kV was applied. Excluding the bufuralol/practolol pair, baseline separation of all substances was achieved in the developed CE system within 9 minutes. A linear relationship (R(2) 0.8752) between the sensitivity of the applied potentiometric detector and the parameter log P characterising the hydrophobicity of the analytes was demonstrated. The best observable limits of detection (LODs) were obtained for the highly hydrophobic substances, i. e. bufuralol (8.10 x 10(-8) M injected concentration, S/N = 3), propranolol, alprenolol, and clenbuterol (ca. 1.10 x 10(-7) M). In the case of hydrophilic catecholamines and carbuterol their LODs with potentiometric detection were lowered by a factor of almost one thousand, reaching a value of 6.6 x 10(-5) M.

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“…Its high sensitivity, specificity, and easy combination with chromatographic techniques make it the method of choice of many analysts. Influence of solvent properties on the efficacy, speed of analysis, and detection sensitivity and performance in separation systems such as capillary electrophoresis-mass spectrometry and electrospray ionization mass spectrometry cannot be neglected (60,61). For example, the physical properties of the solution such as surface tension, conductivity and viscosity affect the mechanism by which ions are produced during electrospray ionization.…”

Section: Mass Spectroscopymentioning

confidence: 99%

Impact of Surface Tension in Pharmaceutical Sciences

2009

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-Surface chemistry has a large influence in many industries. In the life sciences, surface area is gaining importance in the characterization of materials during their development, formulation and manufacturing. The chemical activity, adsorption, dissolution, and bioavailability of a drug may depend on the surface of the molecule. In order to meet manufacturing challenges and develop new and better performing products with improved qualities, knowledge of surface tension is of utmost importance. An attempt has been made in this paper to review the application of interfacial tension in the key domains of pharmaceutical applications.

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Influence of solvent properties on separation and detection performance in non-aqueous capillary electrophoresis–mass spectrometry of basic analytes

Cited by 31 publications

References 35 publications

Analysis of the lipophilic peptaibol alamethicin by nonaqueous capillary electrophoresis-electrospray ionization-mass spectrometry

Analysis of the lipophilic peptaibol alamethicin by nonaqueous capillary electrophoresis-electrospray ionization-mass spectrometry

Hydrophobicity‐aided potentiometric detection of catecholamines, beta‐agonists, and beta‐blockers in a mixed‐solvent capillary electrophoresis system

Impact of Surface Tension in Pharmaceutical Sciences

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