Integrated dual-mode analytical device combining gas pressure and distance readout for rapid analysis of urea

Urea (CO(NH₂)₂) is a simple organic compound that is widely present in nature, the human body and the food industry. In the dairy industry, the deliberate addition of urea to milk leads to an overestimation of protein content. Although urea has low biological toxicity, excessive intake can still have adverse effects on health. Therefore, rapid analysis of urea in milk samples is of great significance.

In this work, a gas pressure and distance readout dual-mode analytical system/device was developed for the rapid detection of urea. Urea and NO₂^- undergo a specific reaction under acid conditions to generate CO₂ and N₂ gases, causing a significant pressure change inside the sealed reaction bottle, which can be readout by a portable gas pressure meter. Simultaneously, this pressure change can be converted into the movement distance of dye through a home-made distance reading device, so that a highly sensitive dual-mode analytical system was established. Under the optimal conditions, the system was applied to the analysis of urea in several milk samples and one certified reference material of artificial urine (BWZ6301-2016), with recoveries ranging from 93 to 106%.

This device offers advantages such as portability, ease of operation, low cost and rapidness, making it an ideal new strategy for rapid analysis. It holds promise for the rapid detection of urea in food samples.