Mass spectrometry (MS) measures the mass-to-charge ratio of molecular species from 100 Da to 100 kDa with extremely high accuracy 1,2.However, the performance largely degrades on the measurement ...

Consisting of four parallel metal rods on which a fixed direct-current voltage and alternating radio-frequency voltage are applied, quadrupole mass filters allow users to selectively filter all ions ...

An ultrasensitive experiment comparing protons with their antimatter counterparts found no difference in the ratios of their charge to mass, researchers report in the Aug. 13 Nature.