Kim Eunyoung, Jun Taehyun, Kim Ah Reum, Kwak Byeong Sub, Park Hyunjoo
Korea Electric Power Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejeon 34056, Republic of Korea.
ACS Omega. 2025 Aug 11;10(33):37025-37038. doi: 10.1021/acsomega.5c00572. eCollection 2025 Aug 26.
Furfural (FF), an intermediate aldehyde compound, can serve as an indicator of the extent of the Maillard reaction on heat-induced food processing and storage, as well as for the aging assessment of the solid insulation of oil-immersed transformers because it is formed by the degradation of cellulosic insulation. By considering the concepts of green analytical chemistry, a new furfural-bis-(4-aminophenyl) disulfide (APDS) colorimetric chemosensory assay, based on the Stenhouse reaction between furfural and APDS, was developed for the quantification of furfural by utilizing UV spectroscopy and colorimetric analyses. A strong correlation between UV-vis absorbance and furfural concentrations was observed, which confirmed the high sensitivity (0.00024 mM furfural) of the reaction system. The color change at 0.005 mM of furfural was noted by the naked eye. This was a unique and highly selective phenomenon because only furfural shows UV absorbance and color change within 450-600 nm of UV radiation, unlike other aromatic and aliphatic aldehydes. The highly sensitive method was applied for the qualification of 0-0.01 mM (0-1 ppm) of furfural in the power transformer insulating fluid. An APDS strip formulated with polyethylene glycol was used as the chromatography paper. This study demonstrates the successful surface Stenhouse coupling between furfural and APDS, as confirmed by X-ray photoelectron spectroscopy analysis. Therefore, this liquid- and solid-based assay is a novel, green analytical method as it uses safer solid APDS instead of toxic liquid aniline that is generally used in conventional methods. In addition, the method is simpler, which makes the on-site analysis possible.
糠醛（FF）是一种中间醛化合物，可作为热诱导食品加工和储存过程中美拉德反应程度的指标，也可用于油浸式变压器固体绝缘的老化评估，因为它是由纤维素绝缘材料降解形成的。基于绿色分析化学的概念，开发了一种新的糠醛 - 双（4 - 氨基苯基）二硫化物（APDS）比色化学传感测定法，该方法基于糠醛与APDS之间的施滕豪斯反应，利用紫外光谱和比色分析对糠醛进行定量。观察到紫外可见吸光度与糠醛浓度之间有很强的相关性，这证实了反应系统的高灵敏度（0.00024 mM糠醛）。肉眼可观察到0.005 mM糠醛时的颜色变化。这是一种独特且高度选择性的现象，因为与其他芳香族和脂肪族醛不同，只有糠醛在450 - 600 nm的紫外辐射范围内显示紫外吸收和颜色变化。该高灵敏度方法用于电力变压器绝缘油中0 - 0.01 mM（0 - 1 ppm）糠醛的定量分析。用聚乙二醇配制的APDS试纸条用作色谱纸。X射线光电子能谱分析证实了本研究中糠醛与APDS之间成功的表面施滕豪斯偶联。因此，这种基于液体和固体的测定法是一种新颖的绿色分析方法，因为它使用更安全的固体APDS代替了传统方法中常用的有毒液体苯胺。此外，该方法更简单，使得现场分析成为可能。
