Quantification of pharmaceutical bitterness using a membrane electrode based on a hydrophobic tetrakis [3,5-bis (Trifluoromethyl) phenyl] borate

Xiao Wu, Takeshi Shiino, Yusuke Tahara, Hidekazu Ikezaki, Kiyoshi Toko

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Technologies for quantifying bitterness are essential for classifying medicines. As previously reported, taste sensors with lipid polymer membranes can respond to bitter hydrochloride substances in pharmaceuticals. However, the acid hydrolysis reaction between the lipid phosphoric acid di-n-decyl ester (PADE) and the plasticizer tributyl o-acetylcitrate (TDAB) led to a deterioration in sensor responses during storage. Given the cost of transportation and preservation for commercialization, membrane components that maintain physical and chemical stability during long-term storage are needed. Here we present a membrane electrode based on hydrophobic tetrakis [3,5-bis (trifluoromethyl) phenyl] borate (TFPB) and a plasticizer 2-nitrophenyl octyl ether (NPOE) for the quantification of pharmaceutical bitterness; they maintain a stable response before and after accelerated deterioration, as well as high selectivity and sensitivity. It is a first attempt to use a completely dissociative substance to replace non-completely dissociative lipids. Our work offsets the long-term stability issue of a bitterness sensor with a negatively charged hydrophobic membrane. Meanwhile, we provide the opportunity to select surface charge modifiers for a membrane surface using ester plasticizers containing oppositely charged impurities.

Original languageEnglish
Article number28
Pages (from-to)1-13
Number of pages13
Issue number2
Publication statusPublished - Feb 2021

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Physical and Theoretical Chemistry


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