| Radon is a radioactive noble gas commonly found in rock,soil, water, materials used in construction and interior decorating, and coal and natural gas combustion. Living in high concentration radon environment for long time can cause skin disease and leukemia.Inhalation of radon and radon progeny, also can damage human respiratory system caused by ionizing radiation. Radon is considered to be the second major factors that lead to lung cancer in addition to smoking, and International Agency for Research on Cancer(IARC)confirmed radon and its progeny as the first carcinogens. Therefore, it is very important to detection radon around our living environment.However, the current detection method of radon are complex, expensive and large, so established a cheap, simple, fast and small interference method for cumulative detection of radon is more practical.In the chapter 2, a new cumulative collection of radon based on radon progeny detection by ICP-MS was proposed. In this study, we based on the principle that radon decays and forms stable lead and its half-life is short to propose a new idea to measure cumulative radon by detecting the lead that resulted from radon decay. We optimized the sampling condition and set up a sampling vessel with a larger ratio of diameter and height as a sample dish. The top of the dish was sealed with a mixed cellulose microporous membrane and the diameter of aperture is0.8?m. We added 2% hydrogen nitrate in the sampling vessel as theabsorbent to collect lead passively. After sampling, we used ICP-MS to detect lead in sample, and determined the mathematical model of the relationship between the radon and the lead. The radon concentration and lead contention of the sample demonstrated a good Logarithmic relationship, the regression equation is CPb=4.96 ln(CRn+1.09)-1.11,r=0.9965,But in a small range of radon concentration, there is a good linear relationship between the two components. the regression equation is CPb=2.3CRn- 0.11, r=0.9964, the detection limit is 495Bq·h/m3. The sensitivity of this method is much better than that of the national standard method of radon measurement, this method is simple and does not require any sample pretreatment.In the chapter 3, we use the character that lead can induce aptamer T30695 to form G-quadruplex, and hinder the formation of double helix structure of T30695 and its complementary strand, to established a novel label-free fluorescent sensors for cumulative detection of radon. The single-strand oligonucleotide T30695 forms a double helix with its complementary strand C-16, so the fluorescent dye PG can embed in double strands produces a strong fluorescence. Radon's progeny lead,induces the G-rich aptamer T30695 to form a tight G-quadruplex structure, which affects the binding of fluorescent dye PG to the double strands. As a result, the fluorescence of the system decreases. The fluorescence intensity of the system is inversely proportional to the lead ion concentration, as well as the cumulative concentration of radon radiation. Using this method, the detection limit of lead is 0.26 n M, and the detection limit of radon is 292Bq?h/m3. This method is simple to operate and has high sensitivity. It is also resistant to interference from other elements, and it can be performed at a low cost with accuratesampling. Most importantly, it protects operational personnel from radiation damage and radioactive contamination.In the chapter 4, we studied the lead induced aptamer AGRO100 formation of G-quadruplex, which resulted in the decrease of the fluorescence intensity of fluorescent dye TO, so that we can detect the cumulative radiation. The vast majority of the literature reported that the fluorescent dye TO can be combined with the G-quadruplex to emit strong fluorescence. However, in this study we found when the dosage of TO is much more than the dosage of aptamer AGRO100, the fluorescence intensity decreased, after lead induced AGRO100 formation of Gquadruplex, the fluorescence intensity of the system is inversely proportional to the lead ion concentration, as well as the cumulative concentration of radon radiation. So we established a label-free fluorescent sensors to detect radon based on its decay daughter. The detection range of this method is 1-8×104Bq·h/m3, the detection limit is611Bq·h/m3. |
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