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Research Facilities

Stable Isotope Ratio Mass Spectrometry (SIRMS)

There are three Continuous Flow-Isotope Ratio Mass Spectrometer (CF-IRMS) systems in the Stable Isotope Laboratory at HKU which serves research and teaching needs for stable isotope ratio users.
System 1: 
Model: (EA) EA3028 / (IRMS) Perspective

Brand: (EA) Eurovector / (IRMS) Nu Instruments

Model: (EA) EA3028 / (IRMS) Perspective


Samples are oxidized, followed by reduction inside the elemental analyzer to convert into CO2 and N2.  Alternatively, they are pyrolyzed  by the HT furnace into CO and H2.  The gases are separated by packed column gas chromatography and analyzed by the IRMS.  This equipment is used for analyzing the isotope ratios of C and N in organic matter (plant/animal tissue) and sediments, as well as H and O isotope ratios in water.


Model: (GC) 7890A / (IRMS) Perspective
System 2

Brand: (GC) Agilent / (IRMS) Nu Instruments

Model: (GC) 7890A / (IRMS) Perspective


Compounds dissolved in volatile organic solvents are first separated by capillary gas chromatography, followed by oxidation or pyrolysis inside a dual furnace to convert into CO2 or H2, and analyzed by the IRMS.  This instrument is used for analyzing the isotope ratios of C and H of individual compounds, such as amino acids, from geological and environmental samples.


System 3
Model: (EA) EA Isolink / (Gas Bench) Gas Bench II / (IRMS) Delta V Advantage

Brand: (EA) Thermo / (Gas Bench) Thermo / IRMS (Thermo)

Model: (EA) EA Isolink / (Gas Bench) Gas Bench II / (IRMS) Delta V Advantage


This isotope ratio mass spectrometer is interfaced with two different sample preparation units:

1. Elemental Analyzer

A temperature ramped GC is included in this EA.  As a result, the analysis time for each sample can be reduced with improved separation, making it suitable for measurement of the isotope ratio sulphur, as well as nitrogen and carbon of bulk organic substrates.

2. Gas Bench with Denitrification Kit

Gas Bench is an innovative solution for high precision on-line isotope and molecular ratio determination of headspace samples. Gas sample is entrained in a helium stream via a sampling needle.  The gas then passes through a CO2 scrubber (Ascarite) and N2O is trapped and concentrated in liquid nitrogen cryo-traps.  The N2O is carried by helium to the IRMS via a gas chromatography column which separates N2O from the interfering gases.  This equipment is mainly used to measure gaseous nitrogen or nitrogen oxides, which are created by biological decomposition of samples containing nitrogen.



Ms. Kit Sum Leung


For sample submission and more information, please visit here.