GB/T 8984.1-1997 Gas Chromatographic Method for Determination of Carbon Monoxide, Carbon Dioxide, and Methane
1 Introduction
Gas chromatography (GC) is a widely used analytical technique that can be used to separate and quantify gaseous components. It has been used to detect and measure levels of carbon monoxide, carbon dioxide, and methane, because of its high sensitivity, efficiency and accuracy.
The GB/T 8984.1-1997 standard specifies the gas chromatographic (GC) method for the determination of carbon monoxide, carbon dioxide, and methane. This standard applies to the determination of carbon monoxide, carbon dioxide, and methane in the air, natural gas, coal gas, fuel gas, and syn gas.
2 Principle
In this method, carbon monoxide, carbon dioxide, and methane are determined by gas chromatographic (GC) analysis. Before the analysis, the sample is mixed with a suitable carrier gas and introduced into the GC column. The column is then heated gradually in order to separate the components according to their boiling points. The components are then detected with a detector and quantified by comparing them to standard reference samples.
3 Reagents
The reagent shall be of grade Ι or ΙΙ purity.
4 Apparatus
The apparatus used in this method includes:
(1) Gas chromatograph.
(2) Flame ionization detector (FID)
(3) Pneumatically operated sample injection valve (POV).
(4) Chromatography column.
(5) Carrier gas (Helium)
(6) Sample gas conditioning system.
(7) Digital recorder.
5 Procedure
5.1 Preparation
(1) Connect the components of the GC system according to the manufacturers instructions.
(2) Set the pressure of the carrier gas (helium) to the pressure recommended by the manufacturer.
(3) Connect the digital recorder to the GC system, and set the gain and time constants.
(4) Set the temperature profile for the column.
(5) Prepare the sample gas conditioning system.
(6) Connect the POV to the GC and set the injection volume.
(7) Install the column and FID in the GC.
(8) Check for leaks in the system.
5.2 Analysis
(1) Turn on the power for the GC and allow the system to reach the desired temperature.
(2) Inject the sample into the GC at a rate of 3 mL/min.
(3) Monitor the chromatogram on the digital recorder.
(4) Record the peak area and peak height of each component.
(5) Calculate the concentrations of carbon monoxide, carbon dioxide, and methane in the sample, using the standard peak areas and peak heights.
6 Calculation
The concentrations of carbon monoxide, carbon dioxide, and methane in the sample shall be calculated according to the following equations:
Carbon monoxide (CO):
Concentration (ppm) = (Area of CO peak/Area of reference peak) x concentration of reference sample
Carbon dioxide (CO2):
Concentration (ppm) = (Area of CO2 peak/Area of reference peak) x concentration of reference sample
Methane (CH4):
Concentration (ppm) = (Area of CH4 peak/Area of reference peak) x concentration of reference sample
7 Safety Precautions
It is necessary to read and understand all safety instructions provided by the manufacturer of the equipment before performing the analysis. Care needs to be taken to ensure that all electrical connections are secure and proper insulation is used. The area must be well ventilated, and the sample should be handled with care in order to avoid any skin contact. It is also important to wear protective clothing and eye protection when handling the samples and reagents.
