Molecular effusion separator

{
  "id": "MLC-T-CHM-007487",
  "term": "Molecular effusion separator",
  "field": "Chemistry",
  "definition": "A GC-MS interface in which the gas chromatograph effluent flows through a porous glass tube inside an evacuated jacket. The lighter carrier gas, such as helium, effuses out through the pores faster than the heavier analyte molecules, so the gas remaining in the tube is enriched in analyte before reaching the ion source. Effusion rate varies inversely with the square root of molecular mass.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "gas chromatography-mass spectrometry"
  ],
  "references": [
    "PAC, 2013, 85, 1515. 'Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013)' on page 1568 (https://doi.org/10.1351/PAC-REC-06-04-06)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/molecular-effusion-separator/"
}