Separation of Amino Acids by Capillary Zone Electrophoresis Using 9-(2-Carbazole) Ethyl Chloroformate as Derivatization Agent
1
Citation
0
Reference
20
Related Paper
Abstract:
A simple and rapid method for the separation of amino acids by capillary zone electrophoresis using 9(2carbazole)ethyl chloroformate (CEOC) as derivatization agent was developed. The effect of some key factors such as pH, temperature and concentration of buffer, on the separation of amino acid derivatives was investigated. 12 amino acids were separated with satisfactory results.Keywords:
Chloroformate
Ethyl chloroformate
Carbazole
Cite
Abstract Chiral analysis of dl ‐amino acids was achieved by micellar electrokinetic chromatography coupled with UV‐excited fluorescence detection. The fluorescent reagent (+)‐1‐(9‐fluorenyl)ethyl chloroformate was employed as chiral amino acid derivatizing agent and sodium dodecyl sulfate served as pseudo‐stationary phase for separating the formed amino acid diastereomers. Sensitive analysis of (+)‐1‐(9‐fluorenyl)ethyl chloroformate‐amino acids was achieved applying a xenon‐mercury lamp for ultraviolet excitation, and a spectrograph and charge‐coupled device for wavelength‐resolved emission detection. Applying signal integration over a 30 nm emission wavelength interval, signal‐to‐noise ratios for derivatized amino acids were up to 23 times higher as obtained using a standard photomultiplier for detection. The background electrolyte composition (electrolyte, pH, sodium dodecyl sulfate concentration, and organic solvent) was studied in order to attain optimal chemo‐ and enantioseparation. Enantioseparation of 12 proteinogenic dl ‐amino acids was achieved with chiral resolutions between 1.2 and 7.9, and detection limits for most derivatized amino acids in the 13–60 nM range (injected concentration). Linearity (coefficients of determination > 0.985) and peak‐area and migration‐time repeatabilities (relative standard deviations lower than 2.6 and 1.9%, respectively) were satisfactory. The employed fluorescence detection system provided up to 100‐times better signal‐to‐noise ratios for (+)‐1‐(9‐fluorenyl)ethyl chloroformate‐amino acids than ultraviolet absorbance detection, showing good potential for d ‐amino acid analysis.
Micellar electrokinetic chromatography
Ethyl chloroformate
Chloroformate
Sodium dodecyl sulfate
Cite
Citations (12)
The analytical potential of a fluorescein analogue, 6-oxy-(N-succinimidyl acetate)-9-(2'-methoxycarbonyl) fluorescein (SAMF), for the first time synthesized in our laboratory, as a labeling reagent for the labeling and determination of amino compounds by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection was investigated. Biogenic monoamines and amino acids were chosen as model analytes to evaluate the analytical possibilities of this approach. The derivatization conditions and separation parameters for the biogenic amines were optimized in detail. The derivatization was performed at 30 degrees C for 6 min in boric acid buffer (pH 8.0). The derivatives were baseline-separated in 15 min with 25 mM boric acid running buffer (pH 9.0), containing 24 mM SDS and 12.5% v/v acetonitrile. The concentration detection limit for biogenic amines reaches 8 x 10(-11) mol.L(-1) (signal-to-noise ratio = 3). The application of CE in the analysis of the SAMF-derivatized amino acids was also exploited. The optimal running buffer for amino acids suggested that weak acidic background electrolyte offered better separation than the basic one. The proposed method was applied to the determination of biogenic amines in three different beer samples with satisfying recoveries varying from 92.8% to 104.8%. Finally, comparison of several fluorescein-based probes for amino compounds was discussed. With good labeling reaction, excellent photostability, pH-independent fluorescence (pH 4-9), and the resultant widely suited running buffer pH, SAMF has a great prospect in the determination of amino compounds in CE.
Boric acid
Cite
Citations (25)
Chloroformate
Sample Preparation
Cite
Citations (5)
Isoindole
O-Phthalaldehyde
Micellar electrokinetic chromatography
Cite
Citations (87)
Cite
Citations (0)
A simple and rapid method for the determination of the 22 protein amino acids by capillary gas chromatography is described. The amino acids were converted into their N(O,S)-isobutoxycarbonyl (isoBOC) methyl ester derivatives and measured by GC with flame ionization detection using a DB-17 capillary column. Arginine was converted into ornithine by arginase treatment prior to the isoBOC reaction. The N(O,S)-isobutoxycarbonylation of amino acids with isobutyl chloroformate was completed within 15 s by sonication in aqueous alkaline media. All of the derivatives were quantitatively resolved as single symmetrical peaks within 9 min by GC on a single column. The detection limits of amino acids were 0.2-4.0 ng per injection, and the calibration curves were linear in the range 0.2-50 micrograms for each amino acid. This method was successfully applied to protein hydrolysate samples. The analytical results of amino acid compositions of several proteins are presented.
Cite
Citations (19)
Abstract A convenient derivatization method of amino acids with l‐fluoro‐2,4‐dinitrobenzene as reaction reagent and a separation system were described. The derivative amino acids were separated on a specific chemically bonded phase column with a simple linear gradient elution consisting of aqueous buffer and methanol. The eluate was detected by common ultraviolet absorption detector at 360 nm. The detection limits of amino acids were as low as 10 picomole. This method has been successfully applied to assay amino acid injection liquor used in hospital. It has good reproducibility and precision. The procedures avoid the requirements of particular derivative equipment and analyzer employed in conventional amino acid analysis.
Amino Acid Analysis
Derivative (finance)
Gradient elution
Cite
Citations (0)
Cite
Citations (0)
Chiral derivatizing agent
Cite
Citations (60)
Ethyl chloroformate
Chloroformate
Cite
Citations (1)