Evaluation of band broadening in chemiluminescence detection coupled to pressurized capillary electrochromatography with an off‐column coaxial flow interface

Abstract

A system of off-column coaxial flow chemiluminescence (CL) detection coupled to pressurized CEC (pCEC) was described. The interface utilized a reactor that introduced postcolumn CL reagent into the capillary effluents in a sheathing flow profile. To compare and evaluate band broadening of analytes caused by the detector, the typical CL compounds luminol and N-(4-aminobutyl)-N-ethylisoluminol (ABEI) were separated and detected by pCEC or capillary HPLC (cHPLC) coupled to CL and UV detector, respectively. The results demonstrated that the band broadening caused by off-column detection interface was minimized due to the fast kinetic nature of the CL reaction. With the proposed pCEC-CL system, the detection limits of luminol and ABEI were 1.0x10(-8) and 8.0x10(-8) mol/L, respectively, which were approximately 100-fold more sensitive than those obtained with UV absorption. In addition, separation and detection of the ABEI-labeled L-lysine (L-Lys) and L-arginine (L-Arg) were accomplished by pCEC-CL method based on the principle of ABEI-potassium ferricyanide-alkaline medium CL reaction system. Under the optimum conditions, good results could be achieved compared with pCEC-UV.

Recent advances in amino acid analysis by CE

“…Lin et al . demonstrated that the band broadening caused by the off‐column detection interface was minimized due to the fast kinetic nature of the CL reaction 33 using an off‐column coaxial flow interface in a CL detector coupled to pressurized CEC.…”

CEC of phytochemical bioactive compounds

“…Due to the simplicity and versatility, UV detection is widely used for determination of phytochemical bioactive components by CEC (Tables 1 and 2), but MS is rarely used 41. Actually, several detection methods, including coordination ion spray MS 129, thermo‐optical absorbance detection 130, ion trap storage reflectron TOF MS 131, 132, condensation nucleation light scattering detection 133, NMR 134–136, LIF 84, 137–142, amperometric detection 143–146, indirect spectrophotometric detection 147, chemiluminescence detection 148–151 and matrix‐assisted laser desorption/ionization MS 152, have been successfully applied for the detection of CEC. Therefore, different detection coupled with CEC for analysis of phytochemical bioactive compounds should be employed to improve the sensitivity and specificity, especially for the bioactive compounds without UV absorptivity.…”

Direct determination of amino acids by pressurized capillary electrochromatography with chemiluminescence detection

“…In the past few decades, the applicability of CL detector connected with CE or microchip CE has been clearly demonstrated [16 -28], and been successfully applied to the determination of metal ions, clinical medicine, carbohydrates, and peptides and so on. In recent 2 years, our group has made extensive efforts to develop the diverse pCEC-CL detection modes that include on-column coaxial flow [29], offcolumn coaxial flow [30] as well as end-column reservoir [31]. The feasibilities of pCEC-CL systems have been fully validated by the evaluation and comparison of its detection mode in technology and methodology.…”