Micellar Capillary Electrophoresis Research Articles

Comparison of selectivities of reversed-phase high-performance liquid chromatography, capillary zone electrophoresis and micellar capillary electrophoresis in the separation of neurohypophyseal peptides and analogues

A number of RP-HPLC systems, including those prescribed in several official monographs, have been evaluated for separating oxytocin, the vasopressins, some clinically important analogues and two additional neurohypophyseal nonapeptides. The separation has been compared with capillary zone electrophoresis and micellar electrophoresis in four micellar systems: cationic, anionic, zwitterionic and neutral. Complete separation was achieved by both RP-HPLC and micellar CE but the importance of charge as a major parameter of separation in CE confers a distinct and useful selectivity to micellar CE based separations.

Low-cost laser-induced fluorescence detector for micellar capillary zone electrophoresis: Detection at the zeptomol level of tetramethylrhodamine thiocarbamyl amino acid derivatives

Tetramethylrhodamine thiocarbamyl (TRTC) amino acid derivatives are determined by micellar capillary zone electrophoresis with laser-induced fluorescence detection. A post-column fluorescence cell, based on a sheath-flow cuvette, is used as the detection chamber. A low-cost and low-power helium-neon laser, operating in the green at 543.5 nm, is used to excite the TRTC-amino acids. The relatively long excitation wavelength, the low-light scatter of the sheath-flow cuvette and the low excitation power result in a very low background signal, which is dominated at room temperature by detector dark current. To minimize the dark current, a cooled photomultiplier tube was used for photodetection. Detection limits (3σ) are 1 · 10 −121 mol (600 molecules) injected onto the capillary.

Sub-femtomole determination of phenylthiohydantoin-amino acids: capillary electrophoresis and thermooptical detection

Twenty phenylthiohydantoin-amino acide (PTH-AA) are separated by micellar capillary electrophoresis in 13.5 min. A low-energy krypton fluoride laser ise used in a thermooptical absorbance detector to produce typical detection limits (3σ) of 9×10 -7 M PTH-glycine injected in a 0.6-nL volume, corresponding to 0.5 fmol (100 fg) of PTH-glycine injected onto the capillary. Detection limits are roughly 3 orders of magnitude superior conventional liquid chromatographic determinations