Dead volume–free flow splitting in capillary electrophoresis

Abstract

In recent years, several dual detection concepts (DDCs) for CE were developed, which consisted of at least one nondestructive detector. For these DDCs, a linear detector arrangement could be used, which is not possible when both detectors are destructive. To overcome this problem, we developed a concept for the splitting of the CE stream utilizing commercially available flow splitters (FSs) that allow the parallel positioning of two destructive detectors. In this proof-of-concept study, T-and Y-shaped FSs were characterized regarding their suitability for DDCs. To keep it simple, a UV detector (UV) and a C 4 D were used for the characterization. The model system consisted of an acetonitrile-based background electrolyte and the two model substances, (ferrocenylmethyl)trimethylammonium iodide and caffeine. CE hyphenated to a UV detector (CE-UV) measurements revealed that the split ratio was about 50% for both FSs. CE-C 4 D was used to evaluate the peak shape in front of and behind the FSs. These measurements showed that there was no significant peak broadening introduced by the FSs. Additionally, there were no changes in the LODs in front of and behind the FSs. Furthermore, the flexibility of the new FS approach allowed the usage of capillaries with different ids (25-75 µm) for injection and detection.

Combining amperometry and mass spectrometry as a dual detection approach for capillary electrophoresis

“…This was an essential point, because, for the quantification, it was important that the split ratio was stable throughout the measurements. In one of our previous works, we also found a good reproducibility of the CE flow splitting for the used FS [29].…”

“…A Y‐shaped FS (material polyetherimide, dead volume 9 nl, and thru‐hole diameter 100 µm) was used to split the CE flow. A microscopic image and a detailed description of the FS can be found in our previous manuscript [29]. The FS was connected to three capillary pieces.…”

“…Böhm et al. [29] presented a user‐friendly flow splitter (FS) that could be used for flow splitting in CE. Different types of FSs were characterized.…”

“…The splitting of the CE flow is already described in literature but predominately in the context of 2D separations or for the concurrent analysis of cations and anions [26][27][28]. Böhm et al [29] presented a user-friendly flow splitter (FS) that could be used for flow splitting in CE. Different types of FSs were characterized.…”

Sensitive and selective determination of the neonicotinoid nitenpyram utilizing capillary electrophoresis hyphenated to amperometric detection/mass spectrometry

“…The parallel arrangement of AD and MS, which are both destructive detection methods, was achieved by a commercially available flow splitter. This concept combines the high separation efficiency and low sample consumption of CE with two detectors providing complementary information about the sample [13,14]. AD is among the most sensitive detection methods for electroactive analytes and shows good reproducibility and long-term stability in non-aqueous media [15].…”