The diploma thesis includes a study of the role of nutrients, minerals and vitamins in the human body and in plants, a review of analytical methods for the determination of potassium and the determination of one of the minerals, namely potassium, in the following plant samples: fresh bananas, dried bananas, dried persimmons, avocados and potatoes. I chose to use atomic absorption and emission spectroscopy techniques to determine potassium. These techniques are relatively easy to understand and the analysis is quick and straightforward. I also validated the method by checking various parameters.
The theoretical part provides an overview of some micro- and macroelements and an overview of the analytical methods for potassium determination. The experimental part contains a description and procedure for analysis with calibration curves of standards, different concentration ranges, using atomic absorption and emission spectroscopy devices. I also described the sample preparation with freeze-drying and acidic microwave digestion. I tested the stability of the analyte, the comparison between days, the repeatability of the method and the influence of the matrix on the analysis. I also checked and optimized the following analysis parameters: gas flame ratio, slit width, reading time and the number of replicates.
I selected samples containing potassium to examine their concentration and not just the presence of the analyte. I reported the results in grams of potassium per gram of dry sample and in percent (%) by mass. I also researched the recommended daily intake (RDI) of potassium for adults and used these values to calculate how much sample mass a person would need to consume to meet their daily potassium requirements. By analyzing the samples, I was able to partially confirm the predicted order of potassium content in the samples.
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