The LI-7000 CO2/H2O Gas Analyzer is a high performance, dual cell, differential gas analyzer. It was designed to expand on the capabilities of the LI-6262 CO2/ H2O Gas Analyzer. A dichroic beam splitter at the end of the optical path provides radiation to two separate detectors, one filtered to detect radiation absorption of CO2 and the other to detect absorption by H2O. The two separate detectors measure infrared absorption by CO2 and H2O in the same gas stream. The LI-7000 CO2/ H2O Gas Analyzer is a differential analyzer, in which a known concentration (which can be zero) gas is put in the reference cell, and an unknown gas is put in the sample cell.
DIC was analyzed coulometrically using a UIC CM5011 CO2 coulometer combined with a VINDTA3C (Marianda Inc) or SOMMA system, alternatively based on infrared absorption using an AIRICA (Marianda, Inc) and a Li-Cor 7000 as the detector.
A volume of 1.25 mL of sample was acidified using an automated custom-built injection and bubble stripping system coupled to an infrared gas analyzer (LICOR LI7000)
The evolved CO2 gas is delivered to a LiCOR 7000 Nondispersive Infrared gas analyzer for measurement.
The LiCOR 7000 is calibrated annually using WMO traceable standard gases containing known CO2 mole fractions.
The average accuracy of the instrument relative to CRMs is better than 1 μmol per kilogram.
DIC was measured on mercuric chloride poisoned samples by acidification and subsequent quantification of released CO2 using a Li-Cor 7000 CO2 detector.
Samples for Carbon analysis were collected in accordance with JGOFS protocols (Dickson and Goyet 1994) and were measured by infrared absorption analysis of CO2 in a nitrogen gas stream using an automated injection system connected to an infrared gas analyzer (LI-COR LI7000).
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