In a mass spectrometer, what is the initial step after the sample is vaporized?

In a mass spectrometer, after the sample is vaporized, the immediate subsequent step is ionization. This process involves converting the vaporized sample into ions, which is crucial for their detection and analysis. The ionization can occur through various methods such as electron impact, chemical ionization, or laser ablation.

Once ionization occurs, the generated ions can be manipulated by electric and magnetic fields, allowing them to be separated based on their mass-to-charge ratios. This separation is fundamental to determining the molecular weight and structure of the sample being analyzed.

The other options do not describe steps that follow vaporization. Cooling would not be a necessary action at this stage, while compression and filtering are not standard procedures immediately following the vaporization of the sample. Therefore, ionization is a critical step that enables the mass analysis of the vaporized substance.