UV-Vis, FTIR, EPR Spectroscopic Analysis of Fungal Metabolites Associated with Biodeterioration of Printed Circuit Board
Jeevandoss Chidambaram Ramdoss
Reliability Test Lab, Central Electronics Centre, Indian Institute of Technology Madras, Chennai–600 036, India.
Arumugam Nagarajan *
Fungi and Mould Growth Test Lab, Central Electronics Centre, Indian Institute of Technology Madras, Chennai–600 036, India.
*Author to whom correspondence should be addressed.
Abstract
Background: Printed Circuit Boards (PCBs) are vulnerable to fungal colonization in humid environments, leading to biodeterioration and reduced electronic reliability. In this study, fungal metabolites associated with PCB degradation were analyzed using UV–Vis, FTIR, and EPR spectroscopy to investigate their optical properties, functional groups, and radical species. The spectroscopic analyses revealed diverse biochemical constituents involved in microbial-induced deterioration, providing insights into the mechanisms of PCB degradation and potential mitigation strategies.
Aim: To investigate fungal contamination on printed circuit boards (PCBs) of electronic analytical equipment and to evaluate the role of mould-associated metabolites in polymer degradation and reliability failure.
Study Design: Isolation of fungi from contaminated and functional failure printed electronics board of a gas chromatography instrument, Preliminary characterization of isolated organisms, and analytical evaluation in UV-Vis spec, FTIR, and EPR.
Place and Duration of Study: Mould Growth Test facility of Central Electronics Centre & SAIF IIT-Madras, Chennai, over a period of 5–7 days for microbial incubation and subsequent analytical assessments on PCBs at the end of 30 days.
Methodology: The fungal contaminants were aseptically isolated from the surface of the AC power supply distribution board of the gas chromatography, and organisms were cultured in selective media supplemented with an antibiotic and incubated at 28 ± 2 °C for 5–7 days. Preliminary identification of fungal isolates was performed with lactophenol cotton blue and KOH staining techniques. Growth distribution on PCB surface was analyzed for 30 days at RH of 90-95% and 28 ± 2 °C. UV–Visible spectroscopy (220–450 nm) was employed to detect metabolites involved in the biodegradation of polymers. The functional group and structural modifications are assessed with FTIR spectroscopy. Electron Paramagnetic Resonance (EPR) analysis is used to identify the generation of reactive oxygen species (ROS) involved in the biodegradation process.
Results: UV-Vis spectroscopic analysis revealed in the range of 260–340 nm (π→π* transitions of aromatic compounds) and 380–420 nm, which denotes oxidative degradation and formation of new chromophores. Cladosporium cladosporioides Showed the optimum spectral activity, suggesting a change of aromatic polymer structures, whereas Aspergillus niger, exhibited optimum peak intensity (0.091). FTIR analysis supports significant oxidative degradation by Cladosporium cladosporioides moderate transformation of polymer by Aspergillus niger, and detectable biochemical interaction by Penicillium ochrochloron, In EPR study revealed the formation of a wide range of ROS at various stages of polymer degradation.
Conclusion: The electronic equipment operating in a controlled environment is also liable to fungal contamination, which can significantly contribute to functional failure and reliability issues. Where wide range of organic compounds and different stages of ROS (Semiquinone, Superoxide and Peroxy radicals) support the viability of the organism and biofilm formation. In severe conditions, growth may cause surface insulation degradation, signal loss, and electrical malfunction. These preliminary research findings enlighten the importance of effective environmental monitoring and fumigation of sensitive, sophisticated analytical equipment to ensure long-term functional reliability.
Keywords: Biodeterioration, fungal contamination, polymer degradation, Printed Circuit Board (PCB)