Postcolumn Radionuclide Detection of Low-Energy .beta. Emitters in Capillary Electrophoresis

Abstract

A postcolumn radionuclide detection system for capillary electrophoresis (CE) is described. Eluant from an electrophoresis capillary is directed onto a peptide binding membrane that has been previously coated with a solid scintillator. The membrane is moved in a preselected pattern relative to the fixed capillary outlet during electrophoresis. Light emission from scintillation is imaged onto a charge-coupled device (CCD) using a series of 35-mm camera lenses. Detection of two low-energy beta- emitters (35S and 3H) not previously reported for capillary electrophoresis is demonstrated. The separation efficiencies are similar to those obtained with on-line UV detection. The response for 35S-labeled methionine is linear (r2 = 0.996) from 66 amol to 11 fmol. Detection limits are 88 zmol (0.03 Bq) for 32P-labeled analytes, 17 amol (0.94 Bq) for 35S-labeled analytes, and 8 fmol (8.5 Bq) for 3H-labeled analytes.

At-line coupling of capillary electrophoresis and surface-enhanced resonance Raman spectroscopy

“…The CE -TLC interface is a modification of the design described by Sweedler et al [11] and He et al [10]. The metal coating at the outlet of the separation capillary was a silver-conductive adhesive used for electronics.…”

“…[10,11]) and silica or aluminium oxide TLC plates as substrate, shows good practicability under all but extremely basic conditions. The advantage of the set-up over LC -TLC-SERRS is that the low flow of aqueous effluent can easily be absorbed by the stationary phase of the TLC plate.…”

“…More recently, the authors studied an at-line approach by depositing the CE effluent onto a SERS-active substrate using electro-filament transfer, while a coaxial liquid sheath provided the electrical contact [9]. He et al [10] developed at-line CE -SERS by adapting the metallized outlet capillary designed by Sweedler to achieve electrical contact [11]. The authors compared the performance of various substrates specially developed to record SERS spectra in their set-up and demonstrated the applicability of CE -SERS for a mixture of trans-1,2-bis(4-pyridyl)ethylene and N,N-dimethyl-4-nitrosoaniline, two chlorophenols and two amino acids, all at the 1 mg mL -1 level.…”

Monitoring diclofenac sodium in single human erythrocytes introduced by electroporation using capillary zone electrophoresis with electrochemical detection

“…Measured analytes include the ions K + and Na + [16,17], lactate and pyruvate [18], glutathione after derivatization with monobromobimane [16], the major proteins [19], enzymes [20], and antigens [21]. Research in the Sweedler group [22][23][24][25] was focused on individual nerve cells using CE with postcolumn radiochemical and on-column laser-induced fluorescence detection. In our laboratory, CZE has been applied to determination of glutathione in individual human erythrocytes [26] and mouse peritoneal macrophages [27] by using the electrochemical detection.…”

Peroxyoxalate chemiluminescence detection for capillary electrophoresis using membrane collection

“…The technique is based on depositing the CE effluent onto a membrane and is similar to previously described membrane deposition and detection schemes w x developed for radionuclide detection 17,18 . An advantage of this deposition method is that after a separation the analytes are preserved and can be detected on the membrane using as many detection methods as necessary.…”