pH-sensitive fluorescent organic nanoparticles: Off-on fluorescent detection of furfural in transformer oil

Chao Chang; Lei Han; Yanfang Zhao; Feng Li

doi:10.1016/j.talanta.2019.01.053

pH-sensitive fluorescent organic nanoparticles: Off-on fluorescent detection of furfural in transformer oil

Talanta. 2019 May 15:197:383-389. doi: 10.1016/j.talanta.2019.01.053. Epub 2019 Jan 15.

Authors

Chao Chang¹, Lei Han¹, Yanfang Zhao², Feng Li³

Affiliations

¹ College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, China.
² College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, China. Electronic address: zyftoday@163.com.
³ College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, China. Electronic address: lifeng@qau.edu.cn.

PMID: 30771951
DOI: 10.1016/j.talanta.2019.01.053

Abstract

Furfural content is considered as index to estimate transformer remnant life. Therefore, low cost, highly sensitive methods for determination of furfural are highly desirable. In the present work, we describe a new strategy for furfural detection by tracing the "off-on" fluorescence signals of fluorescent organic nanoparticles (FONPs). Significant H⁺-dependent emission characteristics in aprotic organic solvent was found for our synthesized poly(DOPA)-FONPs. The fluorescence of poly(DOPA)-FONPs can be quickly quenched by hydroxylamine hydrochloride. Furfural can react with hydroxylamine hydrochloride to produce furan-2-carbaldehyde oxime and release proton in a 1:1 proportion. Then H⁺ produced by the reaction caused the fluorescence intensity at 520 nm to increase as a linear function of furfural concentrations. Under the optimum conditions, the linear working concentration range was found to be 0.01-30 mg L^-1 and the LOD for the determination of furfural was 0.0015 mg L^-1. The proposed method was used to determine furfural in transformer oil samples satisfactorily, providing a convenient alternative to conventional techniques.

Keywords: Detection of furfural; Fluorescent assay; Fluorescent organic nanoparticle; Transformer oil; pH-sensitivity.