Study On The Identification Of Common Gasolines By Fast Gas Chromatographic Technique(E-Nose)and Its Appilications

In the fields of both public security and fire protection,the detection of combustion adjuvant residues in fire scenes is one of the major research focuses.Over the past decades,a variety of novel analytical techniques,such as multidimensional gas chromatography analysis technology,ultra-fast gas chromatography analysis technology,on-line pretreatment hyphenated technique,chromatographic analysis center cutting technology and so on,have been widely used for the qualitative and quantitative analysis of trace volatile organic compounds in complex matrixs.These novel techniques provide possible approaches for the detection of combustion adjuvant residues in fire scenes.In this study,a new method for the identification of different kinds of common gasolines was established by fast gas chromatographic technique(E-nose),and then the method was applied in actual fire accidents.The main contents are follows:1.The method for the identification of common gasolines was established by headspace/fast gas chromatography with rapid gas chromatographic analyzer.The obtained optimal detection conditions were follow: double columns 2 m × 100 ?m ID DB5/DB1701 +(Tenax trap)for C4-C26,a headspace of 500 ul,a hydrogen flame detector(FID),an inlet temperature of 250 oC,a sampling time of 5 s,a programmed temperature: 40 oC(30 s)-1 o C/s-280 oC(30 s),a hydrogen(H2)carrier gas,a flow rate of 1.0 mL/min(constant current mode),a detector temperature of 280 oC and an acquisition time of 5min.2.Chromatography analysis data was organized to set up a database with the principal component analysis method(PCA),followed by grouping,selecting sensor and analyzing statistically.Then,a model for the identification of diffenent kinds of common gasolines was established as the impact factor of sensors was above 0.9 andidentify index was no less than 80.The results showed that the model was valid and efficient when the gasoline concentration was more than 10 nl/mL.3.Furthermore,both the rule of the changes of volatile ingredients in gasolines and the background interference by matrixs after their combustion was investigated.The results revealed that the ratio of ingredients in gasolines varied greatly after combustion.The ingredients with lower boiling point were volatilized completely,while a part of the ingredients with higher boiling point could be resided in the surroundings.And thus,the kind of gasolines precursor could be identifled by detecting these residues.It was also found that the kinds of combustion matrixs have a great effect on the gasoline residues.In summary,fast gas chromatography analytical technique together with electronic nose fingerprint data analysis(PCA)method was applied in the identification of gasoline combustion adjuvant,and a model for the identification of different kinds of gasoline were established.This work provided a new protocol for the determination of organic species in complex mixtures.However,only a preliminary work was made on the study of the changes of volatile species in gasolines and the background interference after combustion.In the future,the application of this propsed method in the actual cases will be continued.