Utilization of Plant Material Extracts as Natural Acid-Base Indicators: An Example of At-Home Lab Experiment in the New Normal Learning Set-Up

Abstract

In response to the remote learning and teaching setup in science due to the COVID-19 pandemic, a lab at-home experiment was conducted where various plant materials were prepared and used as natural acid-base indicators for various household substances. The experiment is designed for the students to apply the fundamentals of intensive laboratory for science education: laboratory safety, laboratory apparatus, laboratory techniques, data documentation, and lab report writing. Presented herein are the results obtained during the experiments conducted at home that focused on the application of various plant extracts as natural indicator. Observable color changes showed that the tested plant extracts responded to the acidity and alkalinity of the various household substances. The science behind the color changes is attributed to the presence of various phytochemicals that change colors when protonated and deprotonated. The potential of the results obtained in the experiments is very promising as it can be further developed and optimized to an analytical procedure that can be applied in testing of acidity and alkalinity in various applications such as food safety and quality, environmental monitoring, materials testing, pharmaceutical analysis, and clinical diagnostics. Moreover, the experiment explored here presented lab teaching strategies that can be applied in the remote learning setup: formulate and design a home-based laboratory experiment that will cover the underlying scientific theories and skills and provide the students the opportunity to explore, improvise, apply, and present information that will holistically develop them as science educators for their current and prospective students.

RGB-based colorimetric method for the analysis of water alkalinity using Cordyline fruticosa extracts as visual indicator

“…Even though the plant material has been used in the community for various purposes, its local availability and the presence of plant pigments make it a good candidate as a visual indicator for this study. The presence of various pigments in plants such as anthocyanins and chlorophyll allowed observable color changes in the test solutions when the samples have varying pH values thus can be used to test the level of alkalinity of samples [23]. Overall, the study aimed at developing and testing a colorimetric procedure based on digital image analysis and plant extracts as a visual indicator to test the alkalinity levels of water samples, and to provide alternative protocols with acceptable precision and accuracy that can be used for routine analysis and monitoring.…”