Detection of hexanal and 1-octen-3-ol in refrigerated grass carp fillets using a QCM gas sensor based on hydrophobic Cu(I)-Cys nanocomposite

• Published in: Sensors and actuators. B, Chemical Chemical, 2020-02, Vol.305, p.127476, Article 127476
• Main Authors: Chen, Wei, Wang, Zhenhe, Gu, Shuang, Wang, Jun, Wang, Yongwei, Wei, Zhenbo
• Format: Article
• Language: English
• Subjects: 1-Octen-3-ol; Carboxyl group; Carp; Copper oxides; Correlation analysis; Correlation coefficients; Cubes; Cysteine; Fillets; Freshness; Gas chromatography; Gas sensor; Gas sensors; Hexanal; Hydrogen bonding; Hydrophobicity; Microbalances; Nanocomposites; Nanoparticles; QCM; Quartz crystals; Room temperature; Selectivity; Sensors; Silicon dioxide; Solid phases; Vapor resistance; Water resistance; Water vapor
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2019.127476

•The hydrophobic Cu(I)-Cys nanocomposite showed good sensing properties under 80 % RH.•Hexanal detection in the range of 1−50 ppm and 1-octen-3-ol detection in the range of 1−45 ppm were achieved.•The sensor was able to detect hexanal and 1-octen-3-ol in refrigerated grass carp fillets within 4 storage days. Hexanal and 1-octen-3-ol have been identified previously as freshness indicators of refrigerated (4°C) grass carp fillets and increase from 0 day to 4 days. Thus, a novel quartz crystal microbalance (QCM) gas sensor was fabricated for hexanal and -1-octen-3-ol detection at room temperature with a hydrophobic cysteine sensitized Cu2O (Cu(I)-Cys) nanocomposite as the sensing layer. The QCM gas sensor coated with 10 μL of the hydrophobic Cu(I)-Cys nanocomposite for each side exhibited good reproducibility, hydrophobicity, reversibility, sensitivity, selectivity and stability towards hexanal and 1-octen-3-ol under 80 % RH. The sensing mechanism of the sensor towards hexanal and 1-octen-3-ol was proposed as (1) resistance to water vapor by hydrophobic silica nanoparticles; (2) formation of sulfhydryl compound between cysteine and Cu2O nano cubes; (3) hydrogen bonding interaction between cysteine’s carboxyl group and hexanal (△H =−45.2 kJ/mol) as well as cysteine’s amino group and 1-octen-3-ol (△H =−60.3 kJ/mol) based on Gaussian calculation results. This hydrophobic Cu(I)-Cys nanocomposite based QCM gas sensor was applied to discriminate refrigerated grass carp fillets within 4 storage days. Validation of the proposed sensor was carried out by correlating the frequency shifts with the contents of hexanal and 1-octen-3-ol obtained from solid phase micro extraction-gas chromatography mass spectrometer (SPME-GCMS). The sensor responses showed a good congruence with the SPME-GCMS analysis with a correlation coefficient of 0.96.