Determination Of Aldehydes Metabolites In Exhaled Gas Condensate Of Lung Cancer Patients

Lung cancer is among the most common malignancies, and remains, at the same time, among the most difficult to treat. In the last decade, analysis of exhaled breath condensate (EBC) has gained great interest because sampling is easy, non-invasive and less stressful for the patient than other more invasive techniques. Molecular biomarkers generally can provide prognostic symbols and their diagnostic detection is becoming increasingly important in early diagnosis of various diseases including cancers. There exist some problems in analysis of EBC:low concentration of biomarkers in EBC; the complex matrix will interfere the determination of target analytes; the actual volume of sampling is small. Therefore, it is necessary to establish a reliable method to sample and enrich samples, combined with analytical instrument of high sensitivity to detect biomarkers in EBC.Up to date, solid phase extraction is widely used to purification and enrichment in sample preparation. It is based on the distribution of analysis between sorbent and organic solvent. An on-line SPE-HPLC method provides a continuous analysis process including loading, enrichment,elution and detection. The automatic on-line method has many advantages such as simple operation, fast analysis, little sample consumption, minimizing environmental pollution, and good reproducibility.Based on new materials, two kinds of new solid phase extraction methods were developed, they were combined with high performance liquid chromatography (HPLC) techniques for the determination of aldehydes in human EBC samples. The main research contents are listed as follows:1. An on-line solid phase extraction-high-performance liquid chromatography (SPE-HPLC) method was developed for the determination of aldehydes in human exhaled breath condensate (EBC). EBC sample and2,4-dinitrophenylhydrazine (2,4-DNPH) solution were directly injected into a conditioned LiChrospher(?) RP-4ADS column. Derivative products were adsorpted on the solid phase extraction column, analytical solution were directly into the liquid chromatographic for analysis. The conditions for the derivatization reactions and followed elution of excess2,4-DNPH were optimized. Under the optimized condition, butanal, pentanal, hexanal, heptanal, octanal, and nonanal in15lung cancer patients,5pneumonia patients and10healthy volunteers were determined were determined. The satisfactory results were obtained, the recoveries of this method were between96%-113%. The results show that the proposed method is sensitive and reliable, it is suitable for the determination of aldehydes in EBC samples.2. A new solid-phase extraction method of aldehydes in exhaled gas condensate based on multi-walled carbon nanotubes loading on the white supporter. In the experiment, multi-walled carbon nanotubes was loaded on the white supporter, as solid-phase extraction material. The conditions for the derivatization reactions and extractwere optimized. The method has mang advantages:high efficiency of extraction, low detection limit, good reproducibility, low cost and less dosage of organic solvent, especially the reduced back-pressure was obtained when compared with the multi-walled carbon nanotubes as solid phase extraction material. These curves were linear over the concentration range of0.005-2μmol L-1for six aldehydes. The regression coefficients were higher than0.996.