For rapid detection of carbaryl pesticides, we developed a simple colorimetric detection method based on azo-coupling reaction. Pretreating carbaryl pesticides with an organic base yielded 1-naphthol, which readily reacted with a diazonium salt with a dramatic color change. Since the resulting azo dye can further change color with the organic base used in the pretreatment, phosphoric acid was added to suppress the confounding colorimetric response. We report that this new colorimetric method can selectively detect carbaryl pesticides from other carbamate pesticides within a minute. Moreover, carbaryl can be detected below 10 parts per million (ppm), which is below its permissible exposure limit (∼15 ppm). Finally, we successfully estimated the concentrations of carbaryl pesticides on fruit samples in the presence of natural interferences.

为了快速检测西维因农药，我们开发了一种基于偶氮偶合反应的简单比色检测方法。用有机碱预处理西维因农药，得到1-萘酚，该萘酚易于与重氮盐反应，并发生明显的颜色变化。由于所得的偶氮染料可以进一步用预处理中使用的有机碱改变颜色，因此添加磷酸以抑制混杂的比色响应。我们报告说，这种新的比色方法可以在一分钟内选择性地从其他氨基甲酸酯农药中检测出西维因农药。此外，可检测到的甲萘威低于百万分之十（ppm），低于其允许的暴露极限（〜15 ppm）。最后，在存在自然干扰的情况下，我们成功地估计了水果样品上甲萘威农药的浓度。