石英粉/磷酸盐缓冲溶液体系中羟自由基荧光分光光度法定量检测研究

为了定量检测石英粉/磷酸盐缓冲溶液体系中极低浓度的羟自由基(·OH)，依据对苯二甲酸(TA)在pH中性的缓冲溶液中与羟自由基反应生成唯一稳定且具有很强荧光特性的产物即2-羟基对苯二甲酸(HOTP)，本文建立了滤液最大激发/发射波长EX_max/EM_max=316 nm/422 nm处的荧光强度与HOTP浓度关系的标准曲线，通过检测石英粉与缓冲溶液作用之后滤液的荧光强度，从而间接测定了体系产生的·OH累积浓度。通过重复试验并分析五个不同实验条件下体系产生的·OH累积浓度，最小检出限达到1.59×10-10 mol·L-1，相对偏差为1.20%~7.89%，标准偏差为1.09×10-9~2.17×10-9 mol·L-1，相对标准偏差为3.5%~5.8%，说明该方法具有较高的精确度和较好的重复性。该方法可用于定量检测pH中性溶液中极低浓度的·OH，与其他方法相比，具有明显的检测限低、成本低、灵敏度高、稳定性和重现性好等优势。

Quantitative Detection of Hydroxyl Radical Generated in Quartz Powder/Phosphate Buffer Solution System by Fluorescence Spectrophotometry

Quartz powder would release radical hydroxyl in phosphate buffer solution. In order to detect the quantity of radical hydroxyl with a quite low concentration, the present paper established a fluorescence method. According to the relationship between the concentration of 2-hydroxyl of terephthalic acid (HOTP) and fluorescence intensity at the wavelength of EX_max/EM_max=316 nm/422 nm, a working standard curve was constructed. Then through the filtrated fluorescence intensity obtained from the powder and solution system, cumulative concentration of ·OH can be measured indirectly. By repeating tests and analysis of five different experimental conditions of ·OH cumulative concentration, the minimum detection limit of the method reached 1.59×10-10 mol·L-1, with a relative deviation of 1.20%~7.89%, standard deviation was 1.09×10-9~2.17×10-9 mol·L-1 and the relative standard deviation was 3.5%~5.8%. The method features high accuracy and good repeatability performance. Compared to other quantitative studies, this method might be applied to test radical hydroxy produced in pH neutral solution systems. In addition, it has apparent advantages such as low detection limit, low cost, higher sensitivity, and better stability and reproducibility. That provides the means for the quantitative study of mixed systems consisting of quartz powder and phosphate buffered solution.