Combining C⁴ D and MS as a dual detection approach for capillary electrophoresis

Abstract

The hyphenation of two detectors in combination with separation techniques is a powerful tool to enhance the analytical information. In this work, we present for the first time the coupling of two important detectors for capillary electrophoresis (CE), namely capacitively coupled contactless conductivity detection (C(4) D) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). The elaborated experimental protocol took into account the requirements of separation aspects and the compatibility with both detectors. ESI-TOF-MS requires background electrolytes (BGE) containing only volatile components such as ammonium acetate or formate. These, however, exhibit a rather high conductivity, which is disadvantageous for C(4) D. Thus, the selection of the BGE in an appropriate concentration was undertaken for the determination of various phenolic compounds serving as a model system. The chosen BGE was a 10 mM ammonium acetate/ammonia buffer with a pH of 9. This BGE was a compromise concerning the detection performance of both detectors. The LODs for m-cresol, m- and p-nitrophenol, and 2,4-dinitrophenol were 3.1 μM (C(4) D), 0.8 μM (MS), 0.8 μM (MS), and 1.5 μM (MS), respectively. Moreover, the overall separation efficiency was excellent illustrating that detector-induced band broadening can be neglected in the CE-C(4) D/MS system. The analytical characteristics for the determination of phenolic compounds show the suitability of this dual detection approach and demonstrate the complementary use of C(4) D and MS detection.

Applications of capillary electrophoresis for biopharmaceutical product characterization

“…To enhance sensitivity and selectivity, capillary electrophoresis was coupled with two different detectors, namely capacitively coupled contactless conductivity detection (C 4 D) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) [165][166][167]. Measurements of counterelectroosmotic species in less than 60 s demonstrated the excellent separation efficiency attained.…”

Silver Nanoparticles‐Silsesquioxane Nanomaterial Applied to the Determination of 4‐Nitrophenol as a Biomarker

“…Several techniques are recommended for the determination of 4‐NP in different types of samples, such as HPLC , electrophoresis chemiluminescence , and GC coupled to mass spectrometry . However, electroanalytical techniques, such as voltammetry, have been attracting greater attention in recent years due to the reduction of analysis costs without compromising the figures of merit.…”

Dual‐opposite multi‐walled carbon nanotube modified carbon fiber microelectrode for microfluidic chip‐capillary electrophoresis determination of methyl parathion metabolites in human urine

“…Due to the high separation efficiency, low sample volume requirement, simplicity in instrumentation and short analysis time, capillary electrophoresis (CE) holds a great promise in biological analysis. The analysis of 4‐NP using CE with UV or MS detection has been well established . The sensitivity of CE‐UV detection is, in general, inadequate to indicate early MP exposure.…”