Study On Rapid Determination Of Aldehydes Impurities In Industrial Styrene By Ion Mobility Spectroscopy

Industrial styrene product is an important chemical raw material,which requires less than 100 mg/L of aldehyde impurities.Aldehyde content is an important indicator of product quality.Current detection methods still use the traditional titration method which is complex and time-consuming.It needs to be sampled from the field and sent to the laboratory for analysis,involving sample pretreatment,etc.The analysis time is long,and the test results lag behind the quality control requirements of styrene production process seriously.Therefore,it is of great academic and practical significance to develop a real-time on-site detection method for aldehydes in industrial styrene products.Ion mobility spectrometry(IMS)has many advantages,such as high sensitivity,simple structure,small size,working at room temperature and pressure,etc.It has been widely and successfully applied in the field of safety inspection,but there are few reports on the application of on-line analysis of trace impurities in industrial processes.In view of the above advantages of IMS,it is potential to be used in industrial on-line analysis.In this paper,a research route for rapid detection of aldehyde impurities in industrial styrene products by IMS is proposed.After extensive investigations,almost no ion mobility spectrometry has been reported in the industrial process field because the signals of a large number of industrial products mask the information of trace compounds.In this paper,the types of aldehydes in industrial styrene products were studied by Gas Chromatography-Mass Spectrometry(GC-MS)firstly,then the samples of benzaldehyde and phenylacetaldehyde were analyzed qualitatively and quantitatively by Gas Chromatography-Ion Mobility Spectrometry(GC-IMS).On the basis of the above analysis,the feasibility of fast determination of aldehydes in industrial styrene products by IMS was studied in order to provide theoretical and experimental data support for the development of on-line detection technology of impurity content in industrial styrene products by Ion Mobility Spectrometry(IMS)method.The main research work is as follows:The total aldehyde content of styrene was determined by the current titration method,which was taken from the styrene production plant as the reference data to verify the accuracy of GC-IMS and IMS methods.In view of the main aldehydes in styrene products,the operating conditions of GC-MS were explored.By separating and searching the general database equipped by the GC-MS instrument,the main aldehydes in styrene products were determined to be benzaldehyde and phenylacetaldehyde.A rapid analytical method for the determination of main aldehydes in styrene products by GC-MS was established.The operating conditions were explored by GC-IMS instrument,and a method for the rapid determination of the content of benzaldehyde and phenylacetaldehyde in styrene were established by GC-IMS.Through this method,the characteristic peaks of styrene,benzaldehyde,phenylacetaldehyde and butyl acrylate were determined by library search,the migration index and gas phase retention index were obtained.The Boltzmann standard curves of benzaldehyde and phenylacetaldehyde were plotted,and their quantitative methods were established.Evaluated this method by precisions,detection limits,limit of quantification and recoveries.The detection precisions of benzaldehyde and phenylacetaldehyde were 0.15%and 0.22%,respectively.The detection limits were 0.14 mg/L and 0.25mg/L.The limit of quantification was 0.48 mg/L and 0.81 mg/L respectively.The recoveries of benzaidehyde and phenylacetaldehyde at three spiked levels were also investigated.And the total aldehyde prediction results of this method are consistent with the traditional titration method.The research results show that the established method is feasible.Under the enthusiastic help and professional advice of teachers such as Zhang Yong and Wang Huimin from Beijing Beifen Rayleigh Analyt ical Instruments(Group)Co.,Ltd.,and the exploration of a large number of experiments,an ion mobility spectrometer was built to detection alde hydes in styrene.The rapid detection method of impurity content succes sfully separated the characteristic peaks of styrene,benzaldehyde and ph enylacetaldehyde.Experimental determined the characteristic peaks of sty rene,benzaldehyde,phenylacetaldehyde and butyl acrylate,and their mig ration time was obtained.The linear regression curves of benzaldehyde a nd phenylacetaldehyde were drawn.The quantitative method was establis hed and the method was evaluated.The detection precisions of benzalde hydeand phenylacetaldehyde were 0.23%and 0.35%,respectively,and the detection limits were 0.28mg/L and 1.24mg/L,The limits of benzald ehydeand phenylacetaldehyde and 0.36mg/L were 0.97mg/L respectively.Therecoveries of benzaldehyde and phenylacetaldehyde at the three spike d levels were also investigated.And the total aldehyde prediction results of this method are consistent with the traditional titration method.The results show that IMS can be used for rapid and accurate determination of impurities in styrene products.The research work in this paper shows that it is feasible to use IMS to rapidly detect the content of benzaldehyde and phenylacetaldehyde in styrene production process,which can solve the problem that the traditional titration method seriously lags behind the product control in styrene production process.This research also provides a new idea and method for the development of real-time detection technology of trace substances in industrial process.