Fruit ripening is a progress involving many physiological changes regulated by various plant hormones such as indole-3-acetic acid (IAA) and salicylic acid (SA). The levels of these hormones in fruit with the spatial-temporal resolution can provide detailed information for the study and evaluation of the fruit ripening. Herein paper-based analytical devices and the microsampling technique were coupled for the analysis of IAA and SA in different locations of the tomato fruit during ripening. Because of its excellent electric conductivity, the ITO glass was used as the substrate of the disposable working electrodes and modified with conductive carbon cement. The ITO modified electrodes in the paper-based analytical devices were utilized for analysis of IAA and SA in tiny tomato samples obtained with the technique of microsampling. Our results showed that the amounts of IAA and SA in the locular tissue of tomato fruit decreased via time in the process of ripening. More importantly, the spatial profiling of IAA and SA in immature and mature tomatoes could be directly differentiated at the molecular level. This study suggested that low-cost paper-based electroanalytical devices could become an effective platform for rapid evaluation of the fruit ripening.

果实成熟是一个涉及多种植物激素如吲哚-3-乙酸（IAA）和水杨酸（SA）调控的许多生理变化的过程。水果中这些激素的水平具有时空分辨率，可为水果成熟的研究和评价提供详细信息。本文将基于纸张的分析设备和微量采样技术结合起来，用于分析番茄果实在成熟过程中不同位置的 IAA 和 SA。由于其优异的导电性，ITO玻璃被用作一次性工作电极的基材，并用导电碳水泥改性。纸质分析装置中的 ITO 修饰电极用于分析通过微量采样技术获得的微小番茄样品中的 IAA 和 SA。结果表明，番茄果实在成熟过程中，随着时间的推移，IAA和SA的含量会随着时间的推移而减少。更重要的是，IAA 和SA 在未成熟和成熟番茄中的空间分布可以在分子水平上直接区分。该研究表明，低成本的纸基电分析装置可以成为快速评估果实成熟度的有效平台。