Improving the Molecular Ion Signal Intensity for In Situ Liquid SIMS Analysis.
In situ liquid secondary ion mass spectrometry (SIMS) enabled by system for analysis at the liquid vacuum interface (SALVI) has proven to be a promising new tool to provide molecular information at solid-liquid and liquid-vacuum interfaces. However, the initial data showed that useful signals in positive ion spectra are too weak to be meaningful in most cases. In addition, it is difficult to obtain strong negative molecular ion signals when m/z>200. These two drawbacks have been the biggest obstacle towards practical use of this new analytical approach. In this study, we report that strong and reliable positive and negative molecular signals are achievable after optimizing the SIMS experimental conditions. Four model systems, including a 1,8-diazabicycloundec-7-ene (DBU)-base switchable ionic liquid, a live Shewanella oneidensis biofilm, a hydrated mammalian epithelia cell, and an electrolyte popularly used in Li ion batteries were studied. A signal enhancement of about two orders of magnitude was obtained in comparison with non-optimized conditions. Therefore, molecular ion signal intensity has become very acceptable for use of in situ liquid SIMS to study solid-liquid and liquid-vacuum interfaces. Graphical Abstract ᅟ.
School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Jinan, 250100, China.|W. R. Wiley Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
Yufan
Y
Zhou
Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
Juan
J
Yao
Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.|School of Civil and Environmental Engineering and Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
Yuanzhao
Y
Ding
Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
Jiachao
J
Yu
Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
Xin
X
Hua
W. R. Wiley Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
James E
JE
Evans
School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Jinan, 250100, China.|W. R. Wiley Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
Xiaofei
X
Yu
Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
David B
DB
Lao
Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
David J
DJ
Heldebrant
Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
Satish K
SK
Nune
School of Civil and Environmental Engineering and Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
Bin
B
Cao
W. R. Wiley Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
Mark E
ME
Bowden
Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA. xiaoying.yu@pnnl.gov.
Xiao-Ying
XY
Yu
School of Physics, State Key Laboratory of Crystal Materials and Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Jinan, 250100, China. xuelinwang@sdu.edu.cn.
Xue-Lin
XL
Wang
W. R. Wiley Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA. zihua.zhu@pnnl.gov.
Zihua
0000-0001-5770-8462
Z
Zhu
Biofilm; Cell; Electrolyte; In situ liquid SIMS; Ionic liquid; Molecular imaging; Solid-liquid interface