Development of coconut shell-based in-house quality control material for proximate analysis in solid fuels

The coconut shell-based industry maintains its significant role in the economic growth of the Philippines, with the country being one of the leading exporters of coconut products in the world. Currently, coconut shells are processed into charcoal briquettes and activated carbon. However, due to accidents related to the transport of these commodities, shipping lines have imposed stringent policies to ensure the safe handling of charcoal on board. Furthermore, there is an existing mandate for the accreditation of third-party laboratories for the quality testing of charcoal. The use of control materials such as Certified Reference Material (CRM) ensures the accuracy and reliability of analytical procedures conducted in the laboratory. However, the availability of CRMs is limited and are often too expensive for routine chemical testing. The use of in-house quality control material (IQCM) is a practical approach in establishing quality measurements in the laboratory. In this study, a coconut shell-based in-house quality control material was developed and characterized for proximate analysis of solid fuels. The calculated p -values using one-way ANOVA for the volatile combustible matter and ash from the homogeneity studies were 0.10 and 0.90, respectively. Furthermore, a trend analysis was established for the monthly stability study. Evaluation of homogeneity and stability data showed that the IQCM is sufficiently homogenous and stable and is fit to be used as a quality control material for routine testing of solid fuels in the absence of CRM.