Electrochemical Analysis of Coffee Extractions at Different Roasting Levels Using a Carbon Nanotube Electrode

Ryotaro Wada, Shota Takahashi, Hitoshi Muguruma, Naomi Osakabe

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


This study reports on the electrochemical analysis of coffee extractions at different roasting levels by using a carbon nanotube (CNT) electrode. The roasting levels, ranging from 1 (low) to 6 (high), were determined according to the roasting time after fixing the roasting temperature. Level 1 roasting resulted in light roasted beans and level 6 in dark roasted ones. Based on the roasting level, the concentration of chlorogenic acids, including 3-caffeoylquinic (3CQ), 4-caffeoylquinic (4CQ), and 5-caffeoylquinic (5CQ) acid, can be determined. Cyclic voltammetry (CV) experiments revealed that the reduction current at +0.27 V was proportional to the concentration of chlorogenic acids. Highperformance liquid chromatography (HPLC) revealed an inverse correlation between the roasting level and chlorogenic acid amount. The total amounts of chlorogenic acids in coffee extractions determined by HPLC were in agreement with those obtained by CV using the CNT electrode at roasting levels 1 – 5. At level 6, the amount of chlorogenic acids determined by the current peak was larger than that detected by HPLC. As a result, the chlorogenic acid amount was overestimated in the CV experiment at +0.27 V, indicating that electrochemically active materials were generated at level 6. The CV profile showed that the reduction peak at +0.10 V increased with an increase in roasting level. Thus, the peak intensity at +0.10 V can be used to evaluate the roasting level even if the concentration or dilution conditions are provided.

Original languageEnglish
Pages (from-to)377-380
Number of pages4
JournalAnalytical Sciences
Issue number2
Publication statusPublished - 2021


  • Carbon nanotube
  • chlorogenic acid
  • coffee infusion
  • cyclic voltammetry
  • redox reaction
  • roasting level

ASJC Scopus subject areas

  • Analytical Chemistry


Dive into the research topics of 'Electrochemical Analysis of Coffee Extractions at Different Roasting Levels Using a Carbon Nanotube Electrode'. Together they form a unique fingerprint.

Cite this