Categories of exhibits
Septum inlet
Exhibit no. 721
In mass spectrometry, the sample must first be introduced into the ion source. The septum inlet is used to introduce gaseous and volatile liquid samples. It comprises a heated reservoir into which the sample is injected via a septum. At low pressures and high temperatures employed, the sample vapors diffuse through a system of valves into the ion source where they can be ionized.
The exhibit is a septum inlet from the ZAB-EQ sector mass spectrometer manufactured by VG Analytical Ltd. in 1986. It consists of a heated metal reservoir with a fine bore glass capillary coupling to the ion source and two valves to facilitate pump-out. The whole assembly was heated and the temperature was monitored with a thermocouple. The reservoir was normally kept at a temperature of about 200 °C. The septum inlet was used for calibrating the instrument with heptacosa (perfluorotributylamine) or perfluorokerosene (PFK, a mixture of perfluorinated alkanes).
