PM_(2.5)中丙二醛的检测、浓度特征及氧化损伤的研究

Detection, Seasonal Characteristics and Oxidative Damage of Malondialdehyde in PM_(2.5)

以和田市城区2014年采集的大气PM_(2.5)样品为实验对象,将0.1 g的PM_(2.5)样品膜与2-硫代巴比妥酸(0.2%)和三氯乙酸(20%)混合显色液反应,用可见光分光光度计测定反应产物的吸光度,通过正交实验来优化PM_(2.5)膜中丙二醛(MDA)的提取及测定条件,结果表明,在反应温度90℃、超声和加热时间40 min、显色剂用量为45 mL时,反应产物在532 nm处具有稳定的最大吸收峰。对和田市城区PM_(2.5)及MDA质量浓度的变化特征分析结果表明,和田市城区4个季节PM_(2.5)平均质量浓度由高到低顺序分别为春季(1 096.67±369.60)μg/m^3、夏季(1 016.16±708.00)μg/m^3、秋季(686.88±525.00)μg/m^3和冬季(214.54±94.70)μg/m^3。MDA平均质量浓度的变化范围为1.10～7.75 ng/m^3,其平均值最高为夏季(4.43±1.80)ng/m^3,最低为春季(1.42±0.60)ng/m^3,冬季与秋季相当,分别为(2.93±0.70)ng/m^3和(2.83±0.80)ng/m^3;最终,将PM_(2.5)膜中MDA的质量浓度与相应的TD_(30)(体外DNA氧化损伤达到30%的剂量)进行相关性分析得出,无论是全样还是水样的TD_(30)值均随MDA浓度的升高而呈降低的趋势。其中,全样与MDA质量浓度的相关性更为显著(r=-0.597,显著性P<0.01)。

Taking the atmospheric PM2.5 samples as the experimental object, which were collected in Hotan city in 2014. Optimized the extraction condition of malondialdehyde(MDA) in PM2.5. The visible Spectrophotometer was used to determine the reaction product, which PM2.5 sample membrane(0.1 g) was mixed with 2-thiobarbital acid(0.2%) and trichloroacetic acid(20%). The results shown that, the optimum condition: temperature is 90 ℃, the ultrasonic time and heating time is 40 min, and the dosage of chromogenic agent is 45 mL. The concentration of PM2.5 from high to low order is spring(1 096.67±369.60) μg/m3, summer(1 016.16±708.00) μg/m3, autumn(686.88±525.00) μg/m3 and winter(214.54±94.70) μg/m3, respectively. The MDA concentration range is 1.10~7.75 ng/m3, and the average value was the highest in summer(4.43±1.80) ng/m3, lowest in spring(1.42±0.60) ng/m3, similar seasonal patterns of winter and autumn(2.93±0.70) ng/m3 and(2.83±0.80) ng/m3. The correlation with MDA concentration and TD30 value(toxic dosages of PM2.5 causing 30% of plasmid DNA damage) analysis showed that both the whole or water soluble fraction TD30 values were decrease with the increase of MDA concentration, the whole fraction showed a notable negative correlation with MDA(r=-0.597, P<0.01).