Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako City, Saitama 351-0197, Japan.
J Chromatogr A. 2012 Mar 16;1229:293-7. doi: 10.1016/j.chroma.2012.01.062. Epub 2012 Jan 30.
The most widely used method for measuring carbonyl compounds in air is 2,4-dinitrophenylhydrazine (DNPH) derivatization followed by high-performance liquid chromatography (HPLC). However, substantial negative interference caused by the presence of ozone in air has been reported. To avoid the influences of ozone, a potassium iodide scrubber (KI-scrubber) is commonly used. However, when air sampling using a DNPH-cartridge and a KI-scrubber is performed under conditions of high humidity, moist potassium iodide in the KI-scrubber traps carbonyls before they reach the DNPH-cartridge. Moreover, wet KI reacts with I(2) to form KI(3) and this oxidative reagent moves to the DNPH-cartridge and destroys the DNPH and DNPhydrazone derivatives. In order to alleviate these problems, new ozone scrubbers (BPE-scrubber, HQ-scrubber) have been developed. BPE-scrubber and HQ-scrubber consist of silica gel particles impregnated with trans-1,2-bis-(2-pyridyl) ethylene (BPE) and hydroquinone (HQ), respectively. BPE reacts with ozone to form pyridine aldehyde and HQ reacts with ozone to form benzoquinone. The amounts of reducing agent in silica gel (130 mg) for ozone scrubber are 1% (w/w) for BPE-cartridge; 0.2% (w/w) for HQ-scrubber. These scrubbers can be used in air containing 140 μg/m(3) of ozone for 24h at a flow rate of 200 mL/min. When the relative humidity exceeded 80%, KI in the KI-scrubber was gradually moistened and changed to yellow in color. Peak abundance of formaldehyde, acetaldehyde and acetone DNPhydrazones was diminished to 25%, 15%, and 2%, respectively, compared with the BPE-scrubber or HQ-scrubber. When using a BPE-scrubber or HQ-scrubber, decomposition of DNPH and DNPhydrazones was not observed at a wide range of relative humidities (3-97%).
空气中羰基化合物最常用的测定方法是 2,4-二硝基苯肼（DNPH）衍生化，然后进行高效液相色谱（HPLC）分析。然而，空气中臭氧的存在会产生大量的负干扰。为了避免臭氧的影响，通常使用碘化钾洗涤器（KI 洗涤器）。然而，当在高湿度条件下使用 DNPH 管和 KI 洗涤器进行空气采样时，湿润的碘化钾在到达 DNPH 管之前会捕获羰基化合物。此外，湿的碘化钾会与 I2 反应生成 KI3，这种氧化试剂会转移到 DNPH 管并破坏 DNPH 和 DNPhydrazone 衍生物。为了缓解这些问题，已经开发了新的臭氧洗涤器（BPE 洗涤器、HQ 洗涤器）。BPE 洗涤器和 HQ 洗涤器分别由浸渍反式-1,2-双（2-吡啶基）乙烯（BPE）和对苯二酚（HQ）的硅胶颗粒组成。BPE 与臭氧反应生成吡啶醛，HQ 与臭氧反应生成苯醌。臭氧洗涤器中硅胶（130mg）中的还原剂含量分别为 BPE 管的 1%（w/w）；HQ 洗涤器为 0.2%（w/w）。这些洗涤器可以在流速为 200mL/min 时，在空气中含有 140μg/m3 臭氧的条件下使用 24h。当相对湿度超过 80%时，KI 洗涤器中的 KI 逐渐变湿并变成黄色。与 BPE 洗涤器或 HQ 洗涤器相比，甲醛、乙醛和丙酮的 DNPhydrazone 的峰丰度分别减少到 25%、15%和 2%。当使用 BPE 洗涤器或 HQ 洗涤器时，在宽相对湿度范围内（3-97%）没有观察到 DNPH 和 DNPhydrazone 的分解。
