Related Experiment Video
Updated: Sep 17, 2025

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Photoionization/Photoinduced Chemical Ionization Source Based on Radio Frequency Amplitude Modulation on an Ion
Zhigang Fan1,2,3, Baimao Zhang1,2,3, Huiwen Ruan1,3
1State Key Laboratory of Medical Proteomics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.
Abstract:
Photoionization (PI) technology has been widely used for the analysis of volatile organic compounds (VOCs) due to its nondestructive nature and high sensitivity. However, the application of photoionization sources is constrained by inefficient ion transmission under high-pressure conditions and relatively low photon energy. In this study, an ion-funnel-integrated photoionization (IFPI) source was developed. Following a systematic investigation of the effects of radio frequency (RF) amplitude on the ion transmission efficiency and ionization processes, a dual-mode ionization strategy based on RF amplitude (Vpp) modulation was proposed. In the low-amplitude mode (Vpp = 40 V), the focusing performance of the ion funnel enhanced the sensitivity of single-photon ionization (SPI) by over 10-fold. In the high-amplitude mode (Vpp = 80 V), high-sensitivity detection of compounds with higher ionization energies (IEs) was achieved via the charge transfer reaction of O2+ produced by photoelectron ionization (PEI), overcoming the limitation of photon energy. After comprehensive optimization of ion source pressure, RF amplitude, and direct current (DC) voltage difference of the ion funnel, the limits of detection (LODs) of 11 VOCs using time-of-flight mass spectrometry combined with the IFPI source (IFPI-TOFMS) ranged from 2.3 to 32.5 parts per trillion by volume (pptv). Finally, the practical utility of the IFPI-TOFMS in the field of environmental health and public safety was demonstrated through 90-h continuous monitoring of laboratory air and spatial distribution analysis of trichloromethane near an indoor swimming pool.
Related Concept Videos
Chemical Ionization (CI) Mass Spectrometry
Inductively Coupled Plasma Atomic Emission Spectroscopy: Principle
The ions and electrons produced interact with the fluctuating magnetic field created by a water-cooled...
Mass Analyzers: Common Types
Inductively Coupled Plasma Atomic Emission Spectroscopy: Instrumentation
There are three main types of inductively coupled plasma atomic emission spectroscopy (ICP-AES) instruments: sequential, simultaneous multichannel, and Fourier transform instruments, with the latter being less commonly used....
Inductively Coupled Plasma–Mass Spectrometry (ICP–MS): Overview
Atomic Absorption Spectroscopy: Radiation and Light Sources
Two common narrow-range 'line' sources used in AAS are hollow-cathode lamps (HCLs) and...

