A method for the determination of tartaric acid enantiomers using CE with contactless conductivity detection has been developed. Cu(II) as a central metal ion together with L-hydroxyproline were used as a chiral selector, the BGE was composed of 7 mM CuCl2, 14 mM trans-4-hydroxy-L-proline, and 100 mM ε-aminocaproic acid; the pH was adjusted to 5 by hydrochloric acid. Separation with a resolution of 1.9 was achieved in 9 min in a polyacrylamide-coated capillary to suppress the EOF. Various counterions of the BGE were studied, and migration order reversal was achieved when switching from ε-aminocaproic acid to L-histidine. With detection limits of about 20 μM, the method was applied to the analysis of wine and grape samples; only L-tartaric acid was found.
Separation of major environmental pollutants as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) by capillary electrophoresis is reported for the first time. It is not possible to resolve the solutes in an aqueous media. However, the use of methanol and acetonitrile as the background electrolyte (BGE) solvents allowed their rapid separation in an uncoated capillary. A major effort was put into BGE optimization in respect to both separation efficiency and detection for further on-line preconcentration. 5 mmol.L⁻¹ naphthalene-1-sulfonic acid and 10 mmol.L⁻¹ triethylamine dissolved in ACN/MeOH (50:50 v/v) provided best separation and detection conditions. Next, the large-volume sample stacking and the field-amplified sample injection were applied and compared. Large-volume sample stacking improved limits of detection (LODs) with regard to the standard injection by 69 times for PFOA and 143 times for PFOS with LODs of 280 and 230 nmol.L⁻¹, respectively. Field-amplified sample injection improved LODs 624 times for PFOAand 806 times for PFOS with LODs 31 and 40 nmol.L⁻¹, respectively. Both preconcentration methods showed repeatabilities of migration times less than 1.2% RSD intraday and 6.6% RSD interday. The method was applied on PFOA and PFOS analysis in a sample of river water treated with solid-phase extraction, which further improved LOD toward 5.6 × 10⁻¹⁰ mol.L⁻¹ for PFOS and 6.4 × 10⁻¹⁰ mol.L⁻¹ for PFOA and allows the method to be used for river water contamination screening or decomposition studies.
- MeSH
- acetonitrily MeSH
- chemické látky znečišťující vodu izolace a purifikace MeSH
- elektroforéza kapilární metody MeSH
- extrakce na pevné fázi MeSH
- fluorokarbony izolace a purifikace MeSH
- kapryláty izolace a purifikace MeSH
- kyseliny alkansulfonové izolace a purifikace MeSH
- limita detekce MeSH
- methanol MeSH
- řeky chemie MeSH
- rozpouštědla MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
A method for determination of nine brominated phenols as environmental risk compounds was developed by on-line coupled capillary isotachophoresis and capillary zone electrophoresis (ITP-CZE). For ITP step, 1x10(-2) mol L(-1) hydrochloric acid with 3x10(-2) mol L(-1) ammediol pH 9.1 was used as the leading electrolyte, and 3x10(-2) mol L(-1) beta-alanine with 2x10(-2) mol L(-1) sodium hydroxide pH 10.05 was used as the terminating electrolyte. As the background electrolyte for CZE separation, 2.5x10(-2) mol L(-1) beta-alanine with 2.5x10(-2) mol L(-1) lysine pH 9.6 was used. All electrolytes contained 0.05% or 0.1% (m/v) hydroxyethylcellulose to suppress the electroosmotic flow. UV detection at wavelength 220 nm was used. Detection limits in order of tens of nmol L(-1) were achieved. Good repeatability of migration times (less than 0.33% RSD) and good repeatability of peak areas (less than 7.19% RSD) at concentration level 5x10(-8) mol L(-1) were observed. Developed ITP-CZE method was applied to determination of brominated phenols in spiked tap and river water samples.
