理论模拟和实验对照研究幅值扫描ac对离子阱质谱性能的影响

Effect of Amplitude-Scanning ac on the Performance of Ion Trap Mass Spectrometry

随着离子阱质谱分析技术的广泛应用,离子阱共振激发过程的理论模拟和实验验证对于深入研究离子阱质谱性能具有重要的意义。常见的线性离子阱所使用的共振激发弹出电压ac(alternating current)的设置有两种方式:一种是设定1个很小的恒定值(如1 V_(0-p)),另一种是设定为1个幅值扫描范围。然而,鲜有人对比研究这两种设定方式对离子阱质谱分辨率等相关性能的影响,也尚未有人将该实验结果用理论模拟的方式进行验证。本工作基于自行搭建的小型连续进样接口离子阱质谱平台,利用纳升电喷雾电离源,以利血平为研究对象,通过理论模拟和实验对照研究扫描共振激发对离子阱质谱性能的影响。首先,通过实验研究了恒定ac共振激发和扫描ac共振激发对离子阱质谱分辨率和灵敏度的影响,实验结果表明,ac电压的初始设定应高于一定的阈值,并且使用扫描共振ac激发有利于提高离子阱质谱的分辨率和灵敏度。随后,利用Simion离子光学证明了扫描共振激发ac相比于恒定共振激发ac可以防止阱中离子的提前激发。最后,对100 mg/L芬太尼和那可汀标准样品进行检测,结果表明,利用扫描ac共振激发相比于恒定ac共振激发可将分辨率提高2倍以上。本研究通过理论模拟和实验对照研究幅值扫描ac对离子阱质谱性能的影响,建立了离子阱质谱共振激发过程的理论模拟方法和相关程序,为进一步研究离子阱中更复杂的非线性共振等高阶运动奠定了基础,在一定程度上提升了离子阱质谱的分析性能,加速了离子阱质谱的仪器调试过程。

With the wide application of ion trap mass spectrometry,the theoretical simulation and experimental verification of resonant ejection play an important role in improving the performance of ion trap mass spectrometry.There are two common ways to set the(alternating current)(ac)resonant voltage of ion trap,one is to set a small constant value like 1 V_(0-p),and the other is to set an amplitude-scanning range.However,few people has studied the influence of the amplitude-scanning setting of ac on the analytical performance of ion trap mass spectrometry,and no experimental result has been studied by theoretical simulation neither.In this work,based on a homemade miniaturized ion trap mass spectrometry platform with continuous atmospheric pressure interface,the effect of amplitude-scanning resonance on the performance of ion trap mass spectrometry was studied by theoretical simulation and experimental study using a nano electrospray ionization source,and reserpine was used as the research object.Firstly,the effects of constant ac resonant ejection and amplitude-scanning ac resonant ejection on the resolution and sensitivity of ion trap mass spectrometry were studied experimentally.The experimental results showed that amplitude-scanning resonant ac ejection could improve the resolution and sensitivity of ion trap mass spectrometry,SIMION showed that the amplitude-scanning ac resonant ejection could prevent the ions from being excited in advance compared with the constant ac resonant ejection subsequently.Finally,the application experiments of two kinds of ions,fentanyl and narcotine showed that the resolution of amplitude-scanning ac resonant ejection was more than 2 times higher than that of constant ac resonant ejection.In conclusion,the effect of amplitude-scanning ac on the performance of ion trap mass spectrometry was studied by theoretical simulation and experimental comparison,and the theoretical simulation method and related program of resonance excitation process of ion trap mass spectrometry were established,which laid a foundation for further study of more complex nonlinear resonance and other high-order motion in ion trap.At the same time,the conclusions also help to improve the analytical performance of ion trap mass spectrometry to a certain extent,and accelerate the instrument debugging process of ion trap mass spectrometry.