At present, as a key analytical technique, mass spectrometry has been widely used in biomedicine, food science, homeland security, systems biology, drug discovery and other fields. Mass spectrometry is based on mass-to-charge ratio (m/z) analysis methods with high sensitivity, high accuracy, and universal applicability.
In mass spectrometry, ionization is a critical first step in charging neutral molecules with charge. Today's commercial ionization methods rely mostly on direct current (DC) high pressure to convert sample molecules into gas phase ions in an ion source. However, during ionization, the amount of ions (Q) is not controlled by voltage (V). Therefore, all current ionization methods do not achieve precise control of the amount of ions. Moreover, if a conventional high voltage power supply is used, most (99%) of the charge/current and ions are wasted. Therefore, mass spectrometry currently has a major bottleneck in the development direction of improving sensitivity, sample utilization, and duty cycle. Moreover, the conventionally used high voltage power supply has the disadvantages of being expensive, difficult to carry, and unsafe.
The high voltage output of a fixed charge is just one of the essential characteristics of a triboelectric nanogenerator (TENG). Under the joint guidance of Georgia Institute of Technology, Beijing Institute of Nano-Energy and Systems, Chinese Academy of Sciences, Wang Zhonglin and Facundo Fernández, Li Anzhen and Jin Yunlong formed a cross-faculty cooperation team, using TENG to drive the ion source, realizing the ion source in charge quantity, positive and negative Precise control of many aspects such as sex, signal length and so on. This work provides a completely new controllable parameter for mass spectrometry and is also the first application of nanogenerators in large analytical instruments. Related work has opened up new research and application areas, and was recently published in the latest issue of Nature Nanotechnology.
First, the team successfully achieved electrospray ionization and plasma discharge ionization using TENG. The fixed amount of charge provided by TENG provides unprecedented control over the ionization process. The team implemented the controllable ion generation of nanocoloumb and proposed a related physical model. Through the TENG drive, the duration, frequency and chargeability of the ion pulse can be effectively controlled and minimized sample consumption. The trace charge of TENG avoids the corona discharge phenomenon common in DC high voltage in mass spectrometry, thus achieving the first ultra-high voltage (5-9 kV) nanoelectrospray (nanoESI). This method increases the sensitivity of the electrospray ion source at low concentrations and maximizes sample utilization. Mass spectrometry by TENG-driven ionization has been successfully used to detect a variety of small organic molecules and biomacromolecules, and to achieve sensitivity that can detect hundreds of molecules. TENG-driven AC ion sprays are also used to deposit ionic materials on insulating surfaces.
This research is groundbreaking for the development of both mass spectrometry and TENG.
First, the study achieved the first precise control of the amount of charge during ionization, bringing a new controllable parameter to mass spectrometry, improving the analytical accuracy, and providing the ability to analyze very small samples for chemical and biological detection. The bottleneck problem of mass spectrometry offers new possibilities. And, using TENG allows researchers to synchronize spray time with mass spectrometry time to maximize sample utilization.
At the same time, TENG replaces the original ion spray power supply on mass spectrometry equipment, making it portable for small mass spectrometry devices and providing possibilities in extreme conditions such as military or aerospace applications.
Finally, the study, as the first study to use TENG in equipment and equipment, confirmed that TENG is a simple, safe and effective method for providing high voltage, providing ideas for similar research, driving different instruments for TENG and The process thus laid the foundation for a "controllable self-driven system".