CO2International standards（ISO 5923—84According to regulations on fire extinguishing agents,CO2Concentration not less than99.5%(Volume), moistureContent less than0.01%(Weight), mineral oil less than5mg/kgLiquids from some major industrialized countriesCO2Product labelAccurate, as per Japanese standards（JIS K1106—78）The former Soviet Union standards (ГОСТ) 8050—76）British Standards（BS 4105—76）In accordance with Romanian standards（STAS 2962—76）Wait, different purposes have been specified accordinglyCO2The lowestCO2Content standards. Generally speaking, for welding purposesCO2The lowestCO2The content is99.5%(Volume). foodadditiveCO2The concentration range is98.8～99.8%(Volume). For metal casting moldsCO2The purity requirement is not high, oneGenerally speaking96～99%(Volume). In the fields of electronics industry and scientific research, high-purity carbon dioxide needs to be usedThe table listsCIG、Linde、Matheson、ScottandLiquid Air Corp.Waiting for various high-purity bottled carbon dioxide quality technical indicators from foreign gas companies.

China has two typesCO2Standards have been established, one of which is industrial grade carbon dioxide standards applicable to chemical, welding, and casting industriesType, cooling and other purposes are recommended standards. Another type of carbon dioxide standard for food additives is mandatoryNational standards apply to two types of liquid carbon dioxide products, namely fermentation gas by-products and lime kiln gas or ammonia plant gas by-productsbenzene,Oxygenated organic compounds, vinyl chloride

1、 Food grade CO2 chromatographic analyzerofInstrument conditions

Instrument:GC9560Gas chromatograph with hydrogen flame ionization detector（FID）Fill column sampler, capillary sampler, analytical and concentration device

Analysis column:PEG20Mφ3×4m，FFAP 0.53 mm×50m

Column temperature:50℃ Injector temperature:160℃FIDTemperature:220℃

2、Food grade CO2 chromatographic analyzerofoperate

Accurately take with a syringe2mlThe standard gas in carbon dioxide is injected into the injector and detected by the detector through the analysis columnThe chromatographic workstation calculates the positive factor using the external standard method; Then accurately sample the gas2mlInject into the sampler for analysis, which can be analyzed by colorThe spectral workstation provides the content of the sample gas. If the concentration is low, it can be injected through concentration analysis, and oxygen-containing organic compounds can also be injected through water absorption.

3、Quantitative methods

Quantitative analysis using an external standard method with a known concentration of standard gas

Ci＝Cs×Ai/As

In the formula:Ci—Concentration of components in the sample gas;

Cs—The concentration of components in standard gas;

Ai—Peak area of components in the sample gas;

As—Peak area of components in standard gas;