Development of Low-Cost Spectrophotometry Laboratory Practice Based on the Digital Image for Analytical Chemistry Subject

Abstract

A module for laboratory practice in quantitative analytical chemistry subject has been developed. The method uses digital image colorimetry as a basis for low-cost spectrophotometry analysis. Reduction-oxidation reaction of silver nanoparticle and mercury (II) ion was used as a case study for the colorimetric experiment. The yellow color of silver nanoparticle was faded linearly to colorless with the addition of mercury ion as an analyte. The color change was then recorded with a digital camera and processed through computer software to extract the color information in the form of Red, Green and Blue. The module of laboratory practice was then applied to students in chemical education study program. The gain of the learning process was measured using pre-test and post-test. The results of the study indicate that the students were able to understand the concept of spectrophotometry by using the developed module of digital image colorimetry. Therefore, we conclude that laboratory practice of digital image colorimetry is applicable as an alternative to the traditional spectrophotometry.

A Mobile Analytical Device for On-Site Quantitation of Anthocyanins in Fruit Beverages

“…While a number of different algorisms exist, the RGB (red, green, and blue) color space is the most popular approach to describe a color quantitatively [29,31,32]. As presented in the Supplementary Materials (Figure S2), we have shown that the normalized R value (R/RGB) is the best choice for analyzing the colorimetric assay for anthocyanins on the PDMS chip.…”

“…Digital image analysis has been extensively used for quantifying colorimetric assays, which is typically performed by using a smartphone, digital camera, or scanner to capture the image and process the color information [31]. As such, all mini-vails on the microchip were essentially adapted for performing the colorimetric assays; as shown in Figure 4, the two rows of assay vials with different concentrations of Cy3G showed varied colors, from plain gray to bright pink in the top row (pH 1.0), with essentially no clear color change in the bottom row (pH 4.5).…”

“…Digital image analysis has been extensively used for quantifying colorimetric assays, which is typically performed by using a smartphone, digital camera, or scanner to capture the image and process the color information [31]. While a number of different algorisms exist, the RGB (red, green, and blue) color space is the most popular approach to describe a color quantitatively [29,31,32]. As presented in the Supplementary Materials (Figure S2), we have shown that the normalized R value (R/RGB) is a better choice for analyzing the colorimetric assay for anthocyanins.…”

Implementation of Low-Cost Laboratory in Education: A Systematic Literature Review

“…laboratory experiments are important to achieve learning objectives and to enrich students' Cognitive, Affective and psychomotor abilities. Through this practical learning activity, the concepts and theories learned in the classroom will be observed and verified by students using real experiments (Firdaus et al, 2019). Learning facilities are one of the factors supporting the success of learning activities (Bima et al, 2021).…”

2-LED-µSpectrophotometer for Rapid On-Site Detection of Pathogens Using Noble-Metal Nanoparticle-Based Colorimetric Assays

“…Another example represents a devices that monitors the wavelength-ratiometric resonance Rayleigh scattering signal of the chemical sensor upon white-LED illumination [32]. Other groups developed modules that are based on digital image colorimetry (via smartphone) [33] or make use of a diffraction grating and image processing to measure the particle size and concentration [34], or use a tungsten-filament lamp with optical fibers and a commercial portable spectrometer [35].…”