# Development of a Bitterness Sensor Using Partially Dissociated Amine Compounds

## TL;DR

A new bitterness sensor was developed using partially dissociated amine compounds to reduce interference from anions and improve accuracy in detecting bitter compounds like those in beer.

## Contribution

The novel use of partially dissociated amines in sensor membranes reduces anion interference and increases sensitivity to bitter compounds.

## Key findings

- Sensor membranes with partially dissociated amines significantly reduced interference from anions like nitrate and iodide.
- The TDA membrane showed higher sensitivity to iso-alpha acids (80.4 mV/dec) compared to the conventional TDAB membrane (68.5 mV/dec).
- Partially dissociated lipids offer a new property in taste sensors, improving accuracy for bitter taste assessment.

## Abstract

This study focused on developing an advanced bitterness sensor designed to minimize interference from common anions such as nitrate (NO3−) and iodide (I−) by incorporating partially dissociated amine compounds into the sensor membrane. The conventional bitter sensor (C00) uses fully dissociated quaternary ammonium salt tetradecyl ammonium bromide (TDAB), which typically exhibits high responses to these anions, leading to inaccurate bitterness assessments. To address this issue, we explored the use of three partially dissociated amines—oleylamine (OAm), dioctadecylamine (DODA), and tridodecylamine (TDA)—as lipids in the membrane components. We fabricated sensor membranes and tested their ion selectivity, interference resistance to anion, and sensitivity to iso-alpha acids (IAAs), representative bitter compounds in beer. The results showed that the membranes with partially dissociated amines significantly reduced anion interference. Notably, the sensitivity of the TDA membrane to IAAs was 80.4 mV/dec in concentration, exceeding the 68.5 mV/dec of the TDAB membrane. This enhanced sensitivity, coupled with reduced anion interference, reveals a novel property of partially dissociated lipids in taste sensors, distinguishing them from fully dissociated lipids. These findings pave the way for the development of sensors that can accurately assess a bitter taste and have potential applications in the food and beverage industry.