nanoCEasy: An Easy, Flexible, and Robust Nanoflow Sheath Liquid Capillary Electrophoresis-Mass Spectrometry Interface Based on 3D Printed Parts

Abstract

Capillary electrophoresis-mass spectrometry (CE-MS) is a powerful tool in various fields including proteomics, metabolomics, and biopharmaceutical and environmental analysis. Nanoflow sheath liquid (SL) CE-MS interfaces provide sensitive ionization, required in these fields, but are still limited to a few research laboratories as handling is difficult and expertise is necessary. Here, we introduce nanoCEasy, a novel nanoflow SL interface based on 3D printed parts, including our previously reported two capillary approach. The customized plug-and-play design enables the introduction of capillaries and an emitter without any fittings in less than a minute. The transparency of the polymer enables visual inspection of the liquid flow inside the interface. Robust operation was systematically demonstrated regarding the electrospray voltage, the distance between the emitter and MS orifice, the distance between the separation capillary and emitter tip, and different individual emitters of the same type. For the first time, we evaluated the influence of high electroosmotic flow (EOF) separation conditions on a nanoflow SL interface. A high flow from the separation capillary can be outbalanced by increasing the electrospray voltage, leading to an overall increased electrospray flow, which enables stable operation under high-EOF conditions. Overall, the nanoCEasy interface allows easy, sensitive, and robust coupling of CE-MS. We aspire the use of this sensitive, easy-to-use interface in large-scale studies and by nonexperts.

High‐throughput glycosylation analysis of intact monoclonal antibodies by mass spectrometry coupled with capillary electrophoresis and liquid chromatography

“…The detailed set‐up of the homemade nanoCEasy CE‐MS interface for the CE‐OT coupling is presented by Schlecht et al. [28]. ESI potential was set to 2000 V.…”

“…The resulting separation along with deconvoluted mass spectra is shown in Figure 3A-C (300 μg/ml). CE-MS was performed using the co-axial SL interface (TTS, Agilent) in combination with QTOF MS and using the nanoCEasy interface for CE-OT MS [28,29]. An SL composed out of isopropanol, water, and formic acid (50/49.9/0.1, v/v/v) offered the best results for all couplings.…”

“…The following couplings of the CE-MS detection were used: commercially available tripletube SL interface (TTS; Agilent Technologies, Waldbronn, Germany) with Bruker QTOF-MS (without nebulizing gas) and nanoCEasy CE-MS interface coupled with OT Fusion Lumos. Parameters of the TTS interface are as follows: -5500 V, 0.0 bar nebulizer gas flow, and dry gas flow 8 L/min, 150 • C. The detailed set-up of the homemade nanoCEasy CE-MS interface for the CE-OT coupling is presented by Schlecht et al [28]. ESI potential was set to 2000 V.…”

“…Especially the low sample consumption (few nL) is a big advantage, for example during a clone selection screening. The nanoCEasy CE-MS interface is a sensitive, suitable, and promising interface for this manner [26][27][28], and the two-capillary approach of this interface enables a valve functionality at the end of the CE capillary [29]. CE-MS is well-suited for the characterization of intact proteins, however, rarely applied for the analysis of intact mAbs.…”

Characterisation of a new online nanoLC-CZE-MS platform and application for the glycosylation profiling of alpha-1-acid glycoprotein

“…All capillaries were etched with hydrofluoric acid to reduce the outer diameter to < 150 μm as described elsewhere [34,35]. PVA capillaries were prepared as described elsewhere [36].…”