Design Of Handheld Miniature Mass Spectrometry Based On Faraday Cup

Mass spectrometer is a scientific instrument to determine the composition and content of substances.Traditional laboratory mass spectrometers are too large to be used in the field;miniature mass spectrometers are small,portable,and have good prospects for application.In this paper,we aim to design a handheld miniature mass spectrometer to ensure the performance of the instrument while reducing the performance of the miniaturized mass spectrometer,and the narrow range of application.The main research contents include.First,to address the problems of single ion source and narrow application range of the existing micro mass spectrometer,UV lamp ionization source,atmospheric pressure chemical ionization source,nanoliter electrospray,paper spray and needle spray ion sources were designed and coupled with the miniature mass spectrometer designed in this paper to expand the application range.Second,to enhance the performance of the miniature mass spectrometer,the ion driving mode of quadrupole enhanced dipole resonance excitation is studied,and the sinusoidal sweep voltage amplitude and frequency parameters are optimized to enhance the detection range,resolution and sensitivity of the instrument.Third,to address the high vacuum requirement of electron multipliers,a lownoise Faraday cup was proposed and designed as the ion detector of the miniature mass spectrometer.For the problem of low bandwidth of the Faraday cup prestage transimpedance amplifier circuit,the inverse transfer function was designed for bandwidth compensation.Fourth,the overall design of the miniature mass spectrometer was carried out,and a handheld miniature mass spectrometer with the dimensions of 216mm×210 mm×123 mm,total weight of 5.2 kg,and continuous battery operation time of 2 h was built by applying the studied ion source,RF control parameters,and Faraday ion detector.the resolution,sensitivity,stability,and practical application capability of the instrument were tested.