| Lung cancer is one of the greatest threat to human health, the survival time is short and the mortality rate is high, mainly due to the lack of precise effective early diagnostic tool. In recent years, breath test as a new non-invasive, simple and quick diagnostic techniques have been favored, the changes of gas composition in human breath can be detected to understand the human physiological processes and disease conditions. Because some of the compounds in human exhaled gas (hydrocarbons, aldehydes and ketones) are potential markers which produced in the process of oxidative stress in the body and can reflect the degree of oxidative damage of people. Nowadays, a lot of researches began to focus on these gaseous biomarkers. So for these respiratory gases metabolic markers is expected to provide a theoretical basis for the early diagnosis of cancer. But the concentrations of target compounds in human exhaled gases are very low, in addition, very complex matrix and the little actual sample amount for each take make a direct measurement difficult, sample preparation (such as:enrichment, separation and purification) is therefore required to improve the accuracy and sensitivity of measurement before the actual chromatographic analysis.The appearance of solid phase micro-extraction technique(SPME) makes sample preparation process becomes simple, efficient and time-saving, because this method can integrate enrichment, separation and purification in one step. And it has many advantages, such as reduced sample amount, simple operation, quick analysis speed, good reproducibility and so on.In this paper, a new adsorbent (ZnO-PDMS composite)-based on solid-phase micro-extraction was developed, and it was combined with high performance liquid chromatography or gas chromatography and mass spectrometry for the determination of the potential cancer markers in human exhaled gas.The main contents are as follows,1. In this experiment, ZnO-PDMS nanorods membrane was prepared on the stainless steel mesh as extraction medium. Based on the coating, a new solid-phase micro-extraction method was established, and it was coupled with high performance liquid chromatography for the determination of aldehyde metabolities in the exhaled gas condensate of lung cancer patients. A series of parameters which affect derivatization and extraction were optimized systematically. Under the optimal experimental conditions, the proposed method was applied for the determination of exhaled breath condensate of the lung cancer patients and normal subjects. The recovery of the method was between88%-129%, the limit of detection (LOD) was in range of1.4-12nmol L-1, and the relative standard deviation (RSD) was less than13.2%. The method possesses the advantages including, simple, sensitive and efficient and has been successfully applied for the investigation of aldehydes in exhaled breath condensate samples of healthy people and lung cancer patients. Hence, the method is valid to detecting volatile aldehydes in complex biological samples2. With ZnO-PDMS composite nanorods as extractive coating, we developed a solid phase micro-extraction method, it was combined with gas chromatography-mass spectrometry for the analysis of volatile organic compounds in human breath gas samples. The coating exhibits excellent extraction capacity, good mechanical stability, and long lifetime. The proposed method was applied for the determination of metabolic markers in the exhaled gas of lung cancer patients and healthy subjects. Meanwhile, a series of parameters that affects the extraction efficiency were optimized. Under optimal experimental conditions, the linearity, detection limit, recovery and precision of the method were also investigated. The detection limit (LOD) of the method was in the range of0.16-1.2pg mL"1, the relative standard deviation (RSD) was less than13.8%, the recovery was between68%-118%. It indicates that the method is a reliable and effective method for the analysis of human exhaled breath. |
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