Kai Xu,Xuefeng Zhang,Ming Zhang,Lanhe Zhang,Zicheng Chen
The combination of highly hydrophilic plant fiber and water molecule sensitive material can effectively detect the water content in transformer oil. In this study, two types of rapid response cellulose colorimetric papers (Rp and Bp) were fabricated through a simple impregnation method, with cellulosic fiber serving as the substrate, cresol red/thymol blue as the color developer, boric acid as the pH regulator, and silica aerosol as the filler. Rp and Bp were tested and analyzed using various characterization methods, and their performance in detecting bound water content in transformer oil was investigated. The results indicate that Rp changes from magenta to light yellow and Bp changes from lavender to light yellow with the increase of water content of transformer oil. The water content detection accuracy of both is 92 % and 95 %, respectively. The rapid color change of them is due to boric acid's acidity triggering molecular structure changes in the color developers. After six cycles of use, Rp and Bp still exhibited excellent color-changing properties. Therefore, colorimetric papers have the attributes of rapidity, high efficiency, low cost, and desired accuracy, providing an alternative approach for evaluating transformer oil's water content and showing promising application potential.
Lifan Zhang,Ziyue Lang,Bozhi Lu,Tinglan Yang,Xinyi Zhang,Muxue Wang,Xiaomei Zhang,Hongmei Cao,Daixin Ye
Carbofuran (CBF), which exhibit high toxicity, persistent residues, ease of accumulation, and resistance to degradation, pose serious threats to human health and harm the ecological environment. Therefore, there is an urgent need to develop a rapid and accurate method for detecting CBF. In this work, a low-cost, portable, and easy-to-use paper chip biosensor was developed, integrating smartphones for the detection of CBF pesticide residues. This biosensor facilitates rapid on-site testing, meeting the needs for immediate analysis. CBF has the ability to inhibit acetylcholinesterase (AChE) activity. In the presence of AChE, acetylthiocholine (ATCh) is hydrolyzed to produce thiocholine (TCh). TCh, in turn, can inhibit the catalytic activity of Ni-N-C single-atom nanozymes (SAzyme) synthesized using Ni(OH) 2 nanochip as a metal precursor, which possess high peroxidase activity. Consequently, the concentration of CBF can be determined by observing the resultant color changes. The results showed that this sensor had a good linear response in the range of CBF concentration from 10 to 500 ng/mL, and the LOD was as low as 8.79 ng/mL. In testing three actual samples—Chinese cabbage, cabbage, and lettuce—the recoveries ranged from 81.09% to 125.27%. This demonstrated that the proposed smartphone-based colorimetric paper chip sensor, utilizing Ni-N-C SAzyme, offers an immediate, convenient, and rapid new strategy for detecting CBF.
危险品化学品经营许可证（带存储）