The quadrupole mass analyzer (QR5) operates as a mass analyzer and transmits ions from the MP0 ion optics.

The quadrupole is a square array of circular rods that are charged with a variable ratio of RF and DC voltages. Quartz spacers act as electrical insulators between adjacent rods. The MS applies an RF voltage to the rods, generating an electric field that guides the ions along the axis of the quadrupole. The MS applies the DC quadrupole offset voltage to the quadrupole rods in addition to the resolving DC voltage. The offset voltage accelerates (or decelerates) ions and, therefore, sets the translational kinetic energy (TKE) of the ions as they enter the quadrupole rod assembly.

Figure Side view (left) and end view (right) of the quadrupole mass analyzer

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