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Chua ZQ, Prabhu GRD, Wang YW, Raju CM, Buchowiecki K, Ochirov O, Elpa DP, Urban PL. Moderate Signal Enhancement in Electrospray Ionization Mass Spectrometry by Focusing Electrospray Plume with a Dielectric Layer around the Mass Spectrometer's Orifice. Molecules 2024; 29:316. [PMID: 38257229 PMCID: PMC10821223 DOI: 10.3390/molecules29020316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 12/22/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
Electrospray ionization (ESI) is among the commonly used atmospheric pressure ionization techniques in mass spectrometry (MS). One of the drawbacks of ESI is the formation of divergent plumes composed of polydisperse microdroplets, which lead to low transmission efficiency. Here, we propose a new method to potentially improve the transmission efficiency of ESI, which does not require additional electrical components and complex interface modification. A dielectric plate-made of ceramic-was used in place of a regular metallic sampling cone. Due to the charge accumulation on the dielectric surface, the dielectric layer around the MS orifice distorts the electric field, focusing the charged electrospray cloud towards the MS inlet. The concept was first verified using charge measurement on the dielectric material surface and computational simulation; then, online experiments were carried out to demonstrate the potential of this method in MS applications. In the online experiment, signal enhancements were observed for dielectric plates with different geometries, distances of the electrospray needle axis from the MS inlet, and various compounds. For example, in the case of acetaminophen (15 μM), the signal enhancement was up to 1.82 times (plate B) using the default distance of the electrospray needle axis from the MS inlet (d = 1.5 mm) and 12.18 times (plate C) using a longer distance (d = 7 mm).
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Affiliation(s)
- Zi Qing Chua
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan (Y.-W.W.); (C.M.R.); (K.B.); (O.O.); (D.P.E.)
| | - Gurpur Rakesh D. Prabhu
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan (Y.-W.W.); (C.M.R.); (K.B.); (O.O.); (D.P.E.)
| | - Yi-Wun Wang
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan (Y.-W.W.); (C.M.R.); (K.B.); (O.O.); (D.P.E.)
| | - Chamarthi Maheswar Raju
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan (Y.-W.W.); (C.M.R.); (K.B.); (O.O.); (D.P.E.)
| | - Krzysztof Buchowiecki
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan (Y.-W.W.); (C.M.R.); (K.B.); (O.O.); (D.P.E.)
| | - Ochir Ochirov
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan (Y.-W.W.); (C.M.R.); (K.B.); (O.O.); (D.P.E.)
| | - Decibel P. Elpa
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan (Y.-W.W.); (C.M.R.); (K.B.); (O.O.); (D.P.E.)
| | - Pawel L. Urban
- Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan (Y.-W.W.); (C.M.R.); (K.B.); (O.O.); (D.P.E.)
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
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