Introduction
The study of coloring properties of plant samples has increased practical utility for both textile and academic purposes. In the present laboratory work, the objective was to investigate the properties of three plant pigments. The work consisted of several parts.
In the first step, pigments were isolated from Fresh Berries, Red cabbage leaves, and turmeric powder. The fabrics were dyed using the prepared dye solutions, but this step was skipped due to time constraints. In the third step, spectroscopic measurements were performed, the purpose of which was to investigate the wavelength of maximum absorption of the substance. The fourth step, which was also not performed due to limited resources, was to perform paper chromatography.
Methods
Materials
The materials used for the present laboratory study were materials whose characteristics are shown in Table 1.
Table 1. Characteristics of the data used.
Procedure
Three plant pigment samples — Fresh Berries, Red cabbage leaves, and turmeric powder — were pre-weighed, ground with a mortar and pestle, and dissolved in 200 mL of isopropanol. Each mixture was heated in Erlenmeyer flasks for 30 minutes and, after cooling, was collected in a clean flask. In the second part of the ongoing experiment, it was necessary to dye three pre-prepared pieces of fabric in the previously prepared natural pigment solutions. Still, this part was performed after time constraints.
In the third part of the experimental study, spectrometric measurements were performed for each of the three pigment solutions. Since our group’s spectrometer was not working, the data were collected differently: the results included the study of the wavelength of maximum absorption. In addition, the fourth part of the experiment, the chromatographic measurement, was not performed due to time constraints.
Data and Results
The present laboratory work only allowed the results to be obtained due to limited resources other than measuring the wavelength of maximum absorption for the three plant pigments. Table 2 summarizes the results obtained: this includes both the mass of the substance and the wavelengths of maximum absorption for each sample.
Table 2. Results of mass measurement and spectroscopic observation.
Discussion
The present laboratory work was aimed at studying the spectroscopic and chromatographic properties of three plant pigments. In terms of spectroscopic observations, it can be observed that specific wavelengths were in different color ranges; in other words, the calculated wavelengths and colors of the solutions show a relationship. Due to time constraints, however, only visual characteristics and the wavelength of maximum absorption were collected. Had the chromatographic portion of the work been done, it would have allowed the determination of Rf.
Strictly speaking, paper chromatography determines the ability of molecules to move in the sorbent structure over time: the lighter the molecules are, the longer distance they can travel from a start under gravity (Ford et al., 2019). For the calculation, a control is used: a spot of the solvent, which also travels some distance.
The ratio of the distance for the component to the distance for the solvent is called Rf, and, in general, the larger the value of this index, the more mobile the dissolved pigment is. In addition, comparing Rfs with reference values for each substance allows qualitative identification of unknown samples. In this work, this would allow the identification of the main component of the plant pigment.
Without understanding which berries were used and which components are essential in the three samples studied, the measured wavelength values of maximum absorption are of limited practical value. In general, this would allow the reference values for the three components to be found and the percentage error calculated; however, this could not be accomplished now.
Conclusion
This work aimed to study the properties of plant pigments obtained from Fresh Berries, Red cabbage leaves, and Turmeric powder. However, this goal was only half achieved: only extraction and spectrometry were used, while the staining and paper chromatography steps were omitted due to a lack of resources and time. The results obtained, however, demonstrate the success of the current milestones: three plant pigments were successfully extracted (converted to dissolved form), and spectroscopic studies provided insights into the wavelengths of maximum absorption. In the future, it is proposed that the missing milestones be carried out and more complete information on the three dyes be obtained.
Reference
Ford, B., Cook, B., Tunbridge, D., & Tilbrook, P. (2019). Using paper chromatography for assessing soil health in southwestern Australia [PDF document]. Web.