Analysis Of Volatile Organic Compounds In Pleural Effusion Of Lung Cancer By SPME-Cooled Injection-GC/MS Method

Pleural effusion is a reflection of many diseases of body on the pleura.As the most specific body fluid of patients with lung diseases,it's directly attributable of lung disease closely with the development of the disease.50% of patients with lung cancer are diagnosed with pleural effusion in the process of its disease development,so the differential diagnosis of benign and malignant pleural effusion is of great value for the clinical treatment of lung cancer.Volatile organic compounds(VOCs),whose existence and content are important information of health status,widely exist in human body fluids and tissues.In our previous work,lots of VOCs were detected in pleural effusion by solid-phase microextraction combined with gas chromatography/mass spectrometry(SPME-GC/MS),showing different contents in benign and malignant pleural effusion.However,it was difficult for the separation and detection of low-boiling-points compounds in pleural effusion such as acetone,dichloromethane,ethyl acetatein by SPME-GC/MS due to their extremely low boiling point and small molecular weight.Therefore,an improved method should be carried out for more comprehensive analysis of VOCs in pleural effusion.Firstly,the SPME-GC/MS technology combined with a self-made cooled injection(CI)method was established for the analysis of VOCs in pleural effusion.It showed that the SPME-CI-GC/MS method was more suitable for the analysis of low-boiling-point compounds with higher sensitivity at optimized column temperature condition.As a result,a smaller amount of sample was enough for analysis.Then,the VOCs in collected 28 pleural diffusion samples(11 malignant pleural effusion and 17 benign pleural effusion)were detected by the developed SPME-CI-GC/MS method.A total of 65 volatile organic compounds belonging to nine distinct chemical classes such as alcohols,aldehydes,ketones,esters,alkanes and alkenes,benzene and its derivatives,heterocyclic compounds,terpenes and others,were identified using NIST 2.0.The average peak areas of the chemical classes were determined with quantified ions,showing obvious difference between benign and malignant pleural effusion.Ketones,alcohols,aldehydes and esters in malignant pleural effusion are apparently higher than those in benign pleural effusion.In addition,21 VOCs with high occurrence frequency and high matched-degree,detected in 9 lung cancer and 9 benign lung diseases pleural diffusion,were selected for peak areas comparative analysis.Dichloromethane,ethyl acetate,cyclohexanol,cyclohexanone and 2-ethyl-1-hexanol exhibit greater difference in pleural effusions of lung cancer and benign lung diseases,which might be useful for screening of lung cancer markers.