Date Published: September 24, 2017
Author(s): Xiangpei Yue, Yaoyue Zhang, Wen Xing, Yutong Chen, Chenyang Mu, Zhan Miao, Peichun Ge, Tingting Li, Rongqiao He, Zhiqian Tong.
The existing methods for detecting formaldehyde (FA) in brain samples are expensive and require sophisticated experimental procedures. Here, we established a highly sensitive and selective spectrophotometric method, which is based on a reaction in which FA reacts with colorless reagent 4-amino-3-penten-2-one (Fluoral-P) to produce a yellow compound, 3,5-diacetyl-1,4-dihydrolutidine (DDL), which can be detected by a spectrophotometer at 420 nm at room temperature. The sensitive response time point was found to be at the first hour, and the optimal pH of derivative reaction was pH 6.0. The limit of detection (LOD) and the limits of quantization (LOQ) for detecting FA were 0.5 μM and 2.5 μM, respectively. Using this method, an abnormally high level of FA was detected in both the brains of FA-injected mice and autopsy hippocampus tissues from patients with Alzheimer’s disease. This finding suggests that the modified Fluoral-P method is effective for measuring levels of FA in the brains.
Formaldehyde (FA) is an industrial chemical product that is widely used to manufacture building materials and household products and is released from several sources within indoor environments, such as particle board, household products, and plywood ; hence, a large number of workers and inhabitants are inevitably exposed to FA . Initial studies showed that gaseous FA could cause carcinogenic and fetal abnormalities , and clinical and epidemiological investigations have found that work-related exposure to FA results in headaches, anxiety, fatigue, sleep disorders, in particular, cognitive disorders [4, 5]. In addition, the results of animal experiments have consistently revealed that gaseous FA exposure induced abnormal behaviors, including spatial memory deficits [6–8].
Several decades ago, the colorless reagent, Fluoral-P, was confirmed to be a derivative reagent for the rapid detect FA in waste water, indoor air, and liquor [22, 26, 27], but to our knowledge, was never used to measure FA in brain tissues. In the present study, a highly selective spectrophotometric method using Fluoral-P, which selectively reacts with FA to produce a colored compound-DDL for the sensitive determination of FA in brain samples, was developed. Compared with GC/MS and HPLC methods, the sample preparation process and derivative of the reaction method were relatively simple and straightforward. Herein, this spectrophotometric method is a promising and potential practical application for detecting FA in the brains.
Using this modified Fluoral-P method, an abnormally high level of FA was detected in brain samples of FA-injected mice (Supplementary Figure 3). Taken together, the present spectrophotometric method using Fluoral-P as a derivative reagent for measurement of FA in brain samples constitutes a simple, sensitive, and practicable alternative to well-established methods for determining brain FA and assessing neurotoxicity of excess FA.