RGB-ColorMeter on smartphones as a simple spectrophotometer: An alternative method of teaching spectrophotometry at the vocational high school of chemical analysts

This study aims to improve students' understanding at the Vocational High School of Chemical Analysts on spectrophotometric concepts through experiments using smart phone technology. For this research, The ColorMeter application with matching red green blue (RGB) colors is used as a simple spectrophotometry. The use of smartphone as a simple spectrophotometry in practicum can maximize spectrophotometric learning activities in the classroom since these are often constrained by the limited access to the instrument. Through finding an alternative method, learning objectives can be properly achieved and practical application is easily attained. This RGB – ColorMeter application can be used to read the transmittance of a colored solution by utilizing the complementary colors of the solution being tested. Transmittance data obtained is used to find the absorbance of the solution, so that it can determine the concentration of a substance in the solution. The results showed that the application of RGB - ColorMeter can show a linear graph between concentration and absorbance. The whole process is then carried out individually by each student starting from the stages of designing, utilizing, and reviewing this simple spectrophotometer. Students' understanding of spectrophotometric concepts increases because each student follows the process thoroughly from the beginning to the final stages of the spectrophotometry practicum. Thus, it can be deduced that the application of RGB-ColorMeter can be used as a simple and accessible spectrophotometer in the spectrophotometry practicum at the Vocational High School of Chemical Analysts.