Lee Jaesang, Kim Jungwon, Choi Wonyong
School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea.
Environ Sci Technol. 2007 Aug 1;41(15):5433-8. doi: 10.1021/es070474z.
A chemical actinometer that employs an aqueous solution of ferrioxalate and polyoxometalate (POM: SiW120404-) is proposed as a simple and fast method that quantifies the light intensity of UV radiation in the 300-390 nm range. As a modified ferrioxalate actinometer, illuminated ferrioxalate solution in the presence of POM generates C02 radical anions that lead to the production of blue-colored POM (SiW12O40(5-)) whose concentration can be easily determined spectrophotometrically (by monitoring absorbance at 730 nm). Photoproduction rate of POM- is linearly correlated with the light intensity. The measured quantum yields, phi(POM-), range 0.11-0.21 in the 300-390 nm region and is fairly constant around 0.18 in the 335-380 nm range, which makes this actinometry ideally suited for the rapid measurement of the light intensity in the UVA region such as in common black light sources. This alternative actinometry eliminates the postirradiation analytical procedure (which needs phenanthroline as a complexation reagent for Fe2+ and the subsequent color development) that is required in the standard ferrioxalate actinometry, and it enables the in-situ quantification of the light intensity in a simpler way by monitoring the formation of POM- as a proxy indicator.
一种采用草酸铁和多金属氧酸盐（POM：SiW12O404-）水溶液的化学光量计被提出，作为一种简单快速的方法来量化300 - 390 nm范围内紫外线辐射的光强度。作为一种改进的草酸铁光量计，在POM存在下光照草酸铁溶液会产生CO2自由基阴离子，从而导致生成蓝色的POM（SiW12O40(5-)），其浓度可以通过分光光度法轻松测定（通过监测730 nm处的吸光度）。POM-的光生成速率与光强度呈线性相关。在300 - 390 nm区域测得的量子产率φ(POM-)范围为0.11 - 0.21，在335 - 380 nm范围内相当恒定，约为0.18，这使得这种光量测定法非常适合快速测量UVA区域的光强度，例如常见的黑光源中的光强度。这种替代的光量测定法省去了标准草酸铁光量测定法中所需的辐照后分析程序（该程序需要邻菲罗啉作为Fe2+的络合试剂以及随后的显色），并且通过监测作为替代指标的POM-的形成，能够以更简单的方式对光强度进行原位量化。
