A triple point immersion cell article determines a triple point of a non-metallic analyte and includes: a first cryochamber including a first cryo-zone; a second cryochamber including a second cryo-zone that is: nested and disposed in the first cryochamber; and thermally isolated by the first cryochamber; a third cryochamber including a third cryo-zone, the third cryochamber being: nested and disposed in the second cryochamber; thermally isolated from the exterior environment by the first cryochamber and the second cryochamber; and thermally isolated from the first cryochamber by the second cryochamber; and a fourth cryochamber including a fourth cryo-zone disposed in the third cryochamber; a triple-point pressure vessel disposed in the fourth cryochamber; and a thermowell disposed in the triple-point pressure vessel.