Which method uses a series of voltage and radio frequencies for ion separation?

The Quadrupole Technique is a mass spectrometry method that utilizes a set of four parallel rods to separate ions based on their mass-to-charge ratio. In this technique, an oscillating electric field is applied to the rods, generating a series of voltage and radio frequencies that create stable and unstable paths for ions as they move through the quadrupole. Only ions with specific mass-to-charge ratios can pass through the device at any given time, allowing for the selective filtering and detection of desired ions.

This process is crucial for a variety of applications, including qualitative and quantitative analysis in fields such as pharmaceuticals, environmental testing, and proteomics. The capability to manipulate the voltages and frequencies allows fine control over the separation process, making the Quadrupole Technique a widely used method in analytical chemistry.

In contrast, the other techniques mentioned operate differently, focusing on various principles of ion separation or detection, rather than solely employing voltage and radio frequencies for this specific purpose.