A chemosensor for on-site sensing of ammonia precursor in concrete to avoid a problem of ammonia emission into the indoor space of concrete buildings was designed and implemented. It was found that aqueous extracts of concrete samples containing antifreeze additives and excreting ammonia were colored in the presence of p-dimethylaminobenzaldehyde. This phenomenon was used for the fast visual sensing of main ammonia precursor (urea) in concrete for the first time. The developed sensor consisted of a sensing solid phase based on an adsorbent modified with p-dimethylaminobenzaldehyde. Various adsorbents were investigated for the immobilization of the reagent and it was established that silica adsorbent Silochrom C-120 provided effective retention of the reagent and Schiff’s base formation during the sampling. Moreover, Silochrom C-120 modified with ascorbic acid was proposed to eliminate the oxidant interference. The sensor displayed excellent selectivity and sensitivity with the visual detection limit of 15 mg kg⁻¹ in terms of urea. The chemosensor was successfully applied by builders on different construction sites. Sample preparation and sensing times were about 2 min and 1 min, respectively.

设计并实现了一种化学传感器，用于现场检测混凝土中的氨气前体，以避免氨气散发到混凝土建筑物的室内空间中。结果发现，在对二甲基氨基苯甲醛的存在下，含有防冻剂和排泄氨的混凝土样品的水提物被着色。该现象首次用于快速视觉检测混凝土中的主要氨气前体（尿素）。研发的传感器由基于对-二甲基氨基苯甲醛改性的吸附剂的感测固相组成。为了固定试剂，对各种吸附剂进行了研究，并且确定了二氧化硅吸附剂Silochrom C-120在采样过程中可有效保留试剂和席夫氏碱。而且，提出了用抗坏血酸改性的Silochrom C-120，以消除氧化剂的干扰。该传感器具有出色的选择性和灵敏度，可视检测极限为15 mg kg^-1以尿素计。化学传感器已被建筑商成功应用于不同的建筑工地。样品制备和感测时间分别约为2分钟和1分钟。