基于脉冲高压消减电荷累积的四极杆质谱检测技术研究OA

The stability of mass spectrometers is a key indicator,directly affecting the accuracy and reliability of experimental results.Nevertheless,charge accumulation on the fixed ceramic insulators of quadrupole alters the ion transmission efficiency and the full width at half maximum(FWHM)of mass spectral peaks,thus degrading instrument stability.To quantify the influence of charge accumulation on stability,simulation experiments were carried out.The simulation results revealed that charged ceramics caused obvious deflection of ion trajectories and distortion of the quadrupole field.Moreover,greater bias voltages applied to the ceramics led to more severe spectral peak variations.At a ceramic voltage of 20 V,the ion transmission efficiency decreased by 53.3％,the FWHM shifted by 0.23 amu,and the adverse effect intensified with the increase of mass-to-charge ratio.To solve this issue,the pulsed high voltage charge accumulation mitigation method was proposed.This method consisted of stabilization process,scanning process,and charge elimination process.In the elimination process,a DC high voltage of approximately 500 V amplitude and an RF high voltage with a peak-to-peak value of approximately 6000 V were applied to periodically eliminating charges.Two validation experiments,including FWHM drift monitoring and stability comparison of the mixed standard solution,were performed to verify the performance of the proposed method.In FWHM test,fragment ions of perfluorotributylamine were monitored under the conditions with and without the pulsed high voltage charge accumulation mitigation method.For the stability test,40 consecutive injections of a mixed solution containing hexachlorobenzene,hexabromobenzenen and decabromodiphenyl ether were tested with the two working modes.The average relative standard deviation of peak areas for the three analytes was reduced from 8.61％to 3.93％,which indicated that the proposed method remarkably improved the stability of the mass spectrometer.