Prototype for Detecting Rhodamine B Levels in Syrup Using Filter Paper Test Media

Abstract Rhodamine B is a synthetic dye commonly utilized in the textile, paper, paint, cosmetics, and soap industries. However, it is sometimes found in food and beverages to enhance their visual appeal to consumers. Long-term consumption of Rhodamine B can lead to liver and kidney disorders and may even result in liver cancer. One of the challenges consumers face in monitoring Rhodamine B consumption is the lack of simple tools that enable the general public to perform such testing. A prototype has been designed to detect Rhodamine B dye levels in syrup using filter paper as the testing medium, with the output displayed in terms of Rhodamine B concentration in parts per million (ppm). The device is intended to be user-friendly for the general public. It operates by reading sensor data from the test medium after it has been dipped into the sample. The current detected by the sensor is converted into a frequency by a microcontroller, which then displays the concentration in ppm on an LCD screen according to predetermined RGB value ranges coded into the microcontroller. Testing was conducted on 25 samples with concentration variations of 0 ppm, 30 ppm, 60 ppm, 90 ppm, and 210 ppm. The results showed a decreasing range of RGB values with increasing Rhodamine B concentration, specifically 0 ppm (R=219-220, G=223-225, B=220-222); 30 ppm (R=218-219, G=207-208, B=208-209); 60 ppm (R=215-218, G=197-204, B=203-206); 90 ppm (R=212-214, G=181-182, B=193-196); and 210 ppm (R=210-211, G=162-163, B=188-191). Additionally, UV-VIS spectrometer testing indicated an increase in absorbance values with higher ppm concentrations: 0 ppm (0), 90 ppm (0.529), 240 ppm (1.088), and 360 ppm (1.574). Based on this data, the prototype for detecting Rhodamine B in syrup using filter paper as a medium has been successfully developed. This study established an optimal working distance range for the sensor, positioning the sample medium between 1.25 and 1.5 cm to achieve accurate RGB value readings. The instrument effectively detects Rhodamine B concentrations in test samples based on RGB values read by the sensor, covering a concentration range of 0 to 210 ppm. UV-Vis absorbance testing of Rhodamine B in syrup further validated and confirmed the accuracy of the developed system.