Method for detecting monocyclic aromatic pollutants in engine tail gas

Abstract

The invention discloses a method for detecting monocyclic aromatic pollutants in engine tail gas. The method comprises the following steps: collecting tail gas to be detected by using an engine tail gas sampling unit, and putting the active-carbon tail gas to be detected in a test tube as the sample; adding dichloromethane into the sample, putting the test tube in an ultrasonic extractor to carry out ultrasonic extraction, filtering the extract liquor, evaporating and setting to the marked volume to concentrate the extract liquor, and preserving at low temperature; carrying out chromatographic analysis on the extract liquor preserved at low temperature; and carrying out linear regression by using the concentration of monocyclic aromatics as the horizontal ordinate and the peak area as the vertical coordinate to calculate a standard operation curvilinear equation, substituting the chromatographic result into a standard operation curvilinear equation, and calculating the concentration of monocyclic aromatics in the sample. The invention can quickly and accurately carry out qualitative and quantitative analysis on monocyclic aromatics and has the advantages of high sensitivity and selectivity and good reproducibility; and the relative standard deviation does not exceed 6.5%, the detection limit is 0.003-0.009 mg / m3, and the recovery rate is 87.5-95.2%.

Description

technical field [0001] The invention relates to the detection of pollutants discharged from ignition engines or compression ignition engines, in particular to the detection of single-ring aromatic hydrocarbon pollutants in engine exhaust. Background technique [0002] Aromatic hydrocarbons containing a benzene ring are monocyclic aromatic hydrocarbons (MAHs), including benzene series, benzene multi-substitutions, alkanes, alkenes, and aromatics. Among them, benzene series are closely related to atmospheric photochemical smog and aerosol formation. It is considered to be one of the important precursors for the formation of photochemical smog. Benzene has been determined by the World Health Organization as a strong carcinogen. China's "Comprehensive Emission Standards for Air Pollutants" stipulates the emission limits for 33 pollutants including benzene, toluene and xylene. The U.S. Environmental Protection Agency sets benzene, toluene Various benzene series such as benzene, ...

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Problems solved by technology

[0003] Monocyclic aromatic hydrocarbons mainly exist in gaseous exhaust pollutants. Due to their low boiling point, high saturated vapor pressure, high volatility at room temperature, and a large amount of impurities in engine exhaust, they have great impact on the collection and chromatographic separation of monocyclic aromatic hydrocarbons. Therefore, there is currently no reliable detection method for monocyclic aromatic hydrocarbon pollutants in engine exhaust

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