Merck Lab @ TU Darmstadt, Alarich-Weiss-Strasse 8, D-64287, Darmstadt, Germany.
Science Relations, Merck KGaA, Frankfurter Strasse 250, D-64293, Darmstadt, Germany.
Sci Rep. 2019 Nov 20;9(1):17212. doi: 10.1038/s41598-019-53687-0.
Test strips are convenient tools for rapid, semi-quantitative analysis of a variety of parameters by dipping them for a few seconds in a sample solution followed by a simple colorimetric read-out. Their sensitivity is mainly determined by the reactivity of the test dyes on the reaction zone and is not sufficient for some applications. The detection limit of commercially available free chlorine test strips, for example, is at present not low enough to confirm the absence of this analyte as disinfectant in rinsing solutions after disinfection or to control required residual amounts of chlorine in drinking water. Therefore, we developed a user-friendly lateral flow test which is capable to detect very low amounts of free chlorine. The latter relies on a larger sample volume passing the reaction zone as compared to simple dip test strips. An amount of as low as 0.05 ppm chlorine can, however, only be detected if oxidation stable flow test substrates are used. The eventually developed flow test reaches a 10x higher sensitivity than a commercial dip test. The result is obtained within 4-5 min flow time, whereby no action is required by the user during this analysis time.
测试条是一种方便的工具，可通过将其在样品溶液中浸泡几秒钟，然后进行简单的比色读取，快速、半定量地分析各种参数。它们的灵敏度主要取决于反应区上测试染料的反应性，对于某些应用来说并不足够。例如，市售的游离氯测试条的检测限目前还不够低，无法确认消毒剂在消毒后冲洗液中是否不存在该分析物，或无法控制饮用水中所需的余氯量。因此，我们开发了一种用户友好的横向流动测试，可以检测非常低浓度的游离氯。与简单的浸泡测试条相比，后者依赖于更大的样本量通过反应区。然而，如果使用氧化稳定的流动测试底物，只能检测到低至 0.05 ppm 的氯。最终开发的流动测试比商业浸泡测试的灵敏度高 10 倍。结果在 4-5 分钟的流动时间内获得，在此分析时间内用户无需采取任何行动。
