Direct and rapid screening of calcium carbide in ripened bananas using chemometrics-assisted laser Raman spectroscopy

• Published in: Applied physics. B, Lasers and optics Vol. 129; no. 6
• Main Authors: Odongo, K. O., Kaniu, M. I., Ndung’u, C. N., Wanjohi, J. M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2023; Springer Nature B.V
• Subjects: Acetylene; Additives; Applied physics; Bananas; Carbides; Chemical fingerprinting; Chemometrics; Engineering; Lasers; Optical Devices; Optics; Phosphines; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Principal components analysis; Quantum Optics; Raman spectroscopy; Screening; Slaked lime; Sulfur
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-023-08023-w

We present a novel method, chemometric-assisted laser Raman spectroscopy, for the direct, rapid, and simultaneous screening of harmful chemical additives such as sulfur, acetylene, calcium hydroxide, and phosphine in carbide-ripened bananas. The method entails (i) obtaining spot laser Raman spectral measurements (~ 10 s) from naturally and carbide-ripened bananas, (ii) optimizing the measurements through spectral data pre-treatment techniques and feature selection, and (iii) using principal component analysis to identify the molecular fingerprint regions useful for confirming the presence of calcium carbide. Overall, the turnaround time for the results using this method is approximately 10 min, which is significantly less than that of conventional wet chemistry methods, which would require more than 4 h. Finally, the sulfur wave-shift range (450–500 cm −1 ) was found to be the most accurate (accuracy = 94%, kappa = 0.87) in the discrimination of naturally and carbide-ripened banana samples.