Jurnal Akademika Kimia
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Determination of Hydrolyzed Tannin Content in Cocoa Fruit Peel Waste of MCC 01 Clone, Using UV-Vis Spectrophotometry
Get PDFCocoa Fruit Peel Waste MCC 01 Clone (Theobroma cacao L.) is a traditional medicinal plant with tannins that can be utilized as an anti-bacterial because it contains phenol groups and has antiseptic properties. This study aims to determine the type of tannin compound and the tannin content in cocoa fruit peel waste extract. The maceration method was used to extract the extract using 70% ethanol as a solvent. Qualitative test of tannin type was conducted using C2H4O2 10%, C2H3O2 10%, HCl, FeCl3, and KBr, while quantitative test was conducted using UV-Vis Spectrophotometry at a wavelength of 765 nm. The qualitative test results to determine the type of tannins obtained from cocoa fruit peel waste indicate that it contains hydrolyzed tannins. In the quantitative test, the average tannin content was 4.73 mg/g extract
Analysis of Potassium (K) and Calcium (Ca) in Durian Seeds (Durio Zibethinus Murr)
Get PDFDurian seeds are one of the wastes from durian fruit that has not been optimally utilized due to the community's lack of knowledge and creativity regarding the processing of waste into food that has economic value. This reduces the accumulation of durian seed waste that can pollute the surrounding environment. Durian seeds benefit from being used as food because they are rich in minerals, especially potassium and calcium. This study aims to determine the levels of potassium and calcium contained in durian seeds. Determination of potassium and calcium levels using atomic absorption spectrophotometer (SSA). Potassium levels were analyzed at a wavelength of 766.8 nm, and calcium was investigated at 423 nm. Before the potassium and calcium levels were determined, the moisture content and ash content were first defined in the sample. The results of the analysis of moisture in the sample obtained 2.182 % and ash content of 12.633 %. Further analysis of potassium obtained average results for potassium of 612.605 mg / 100 g and an average for calcium of 15.555 mg / 100 g. The results of this study are expected to be a source of information about potassium and calcium levels in durian seeds. They can be further utilised as an alternative food based on durian seeds, especially in the Parigi Moutong area, Central Sulawesi
Nickel Extraction from Morowali Laterite Ore with Chloride Acid (HCl) – Nitric Acid (HNO3) Solution
Get PDFNickel is a metal of high strategic value for human needs to make stainless steel, batteries, and other products. The amount of nickel reserves in the world is about 72 % in rock oxides, and the rest is in sulfide rocks. However, only about 42 % of total nickel production in the world comes from laterite ore, while nickel sulfide is mainly produced. Research was conducted to determine the optimum nickel extraction parameters in a mixture of nitric acid and hydrochloric acid, and to determine the effect of the solvent volume ratio, temperature, and leaching time parameters on the nickel leaching results from laterite samples. This study uses the taguchi¬larger the better method with each factor having three levels of conditions, namely the volume ratio of the solvent using variations of 1: 1, 1: 2, and 2: 1 then variations in temperature of 30°C, 60 °C, and 90 °C as well as variations in the leaching time of 3 hours, 6 hours, and 12 hours. The optimum conditions for nickel extraction are a parameter ratio of 1:1, a temperature of 90 °C, and a leaching time of 6 hours. The results of atomic absorption spectrophotometer analysis showed that the concentration of Ni2+ at optimum conditions was 10.7895 ppm, and the recovery value was 2.54 %
Analysis of Nitrogen and Potassium in Liquid Organic Fertilizer from Rice Washing and Mature Coconut Water
Get PDFMature coconut and rice washing water contain nitrogen and potassium, which are helpful for plants. This study aims to determine the levels of nitrogen and potassium in liquid organic fertilizer from a mixture of mature coconut water and rice washing water. Nitrogen content was analyzed using the Kjeldahl method. Potassium levels were analyzed using a flame photometer. The results indicated that the best nitrogen and potassium levels were obtained in liquid organic fertilizer with a mixture ratio 50:50, namely N 1.26% and K 1.27%. The highest nitrogen content was obtained in liquid organic fertilizer (LOF) with a mixture ratio of 25:75, 1.40%, and the highest potassium content was obtained in liquid organic fertilizer with a mixture ratio of 50:50, 1.27%. When mixed, the increase in nitrogen and potassium levels was caused by the bacteria in the liquid organic fertilizer, which breaks down protein during digestion
Exploration of Teachers' Creative Thinking Ability Profile in Implementing Chemistry Learning in Senior High Schools
Get PDFThis study addresses the limited empirical evidence regarding chemistry teachers’ creative thinking performance in Indonesia. To fill this gap, the present research aims to explore the creative thinking ability profile of senior high school chemistry teachers. This quantitative descriptive study employed an exploratory design and included 21 chemistry teachers from various provinces in Indonesia. Data were collected using a validated creative thinking questionnaire consisting of four indicators: fluency, flexibility, originality, and elaboration. The results indicated that 66.67% of teachers were in the “Very Good” category, 28.57% in the “Good” category, and only 4.76% in the “Fair” category. Among the indicators, fluency showed the highest average score (91.23%), followed by elaboration (86.67%), flexibility (84.95%), and originality (80.38%). These findings indicate that chemistry teachers demonstrate strong abilities in generating and elaborating ideas. At the same time, originality remains comparatively lower due to systemic constraints such as inflexible education policies and limited pedagogical autonomy. The study also highlights the importance of institutional support, training programs, and collaborative learning environments that promote pedagogical creativity among teachers. Enhancing originality, in particular, requires schools to provide more autonomy and flexibility in instructional planning. Ultimately, the results of this study can serve as a reference for educational policymakers and curriculum developers in designing teacher development programs that not only improve content delivery but also cultivate innovative teaching mindsets, essential for meeting the demands of 21st-century learning
Antioxidant Activity Test of (Acalypha indica L) Extract
Get PDFThe antioxidant activity test of Acalypha indica L has been carried out. This study aimed to determine the IC50 value of the Acalypha indica L extract. The radical concentration of 2,2-diphenyl-1-picrylhydrazyl (DPPH) after adding Acalypha indica L extract was determined using a UV-Vis spectrophotometer. The concentration variations used in Acalypha indica L extract were 15.48 ppm, 30.96 ppm, 46.44 ppm, and 61.92 ppm. The results showed that the IC50 value of Acalypha indica L extract was 41,259 ppm, while the IC50 value of vitamin C as a comparison was 50.626 ppm. Based on the IC50 value data above, it can be seen that the antioxidant of Acalypha indica L extract is robust compared to vitamin C
Determination of Total Phenolic Content and Antioxidant Activity of Tepache Fermented Product as Probiotic Beverage
Get PDFTepache is a fermented beverage from Mexico that is made from pineapple peel. It can improve the balance of good bacteria and reduce the risk of gastrointestinal disease. Pineapple peel contains vitamin C, phenolic compounds, and flavonoid compounds, which have antioxidant function. There have been many studies on making tepache from pineapple peel. However, there is limited research about organoleptic tests with several influencing factors, such as the type of sugar and fermentation time. The research aimed to determine tepache beverages' total phenolic content and antioxidant activity. Tepache beverages are made with pineapple peel, brown sugar, and water, and then fermented for 1, 3, and 5 days. Gallic acid is used as a standard to determine total phenolic content. The DPPH test was carried out to determine its antioxidant activity. The result of the total phenolic contents in tepache beverages for 1, 3, and 5 days of fermentation was 0.0278 mg GAE/g sample, 0.0307 mg GAE/g sample, and 0.0436 mg GAE/g sample—antioxidant activity expressed by IC50 value. IC50 values in tepache beverages for 1, 3, and 5 days of fermentation were 160.198 ppm, 150.639 ppm, and 142.713 ppm. Tepache beverages have low total phenolic content levels and low to medium antioxidant activity
Examining Student Conception of Reaction Rate Through Three-Tier Multi-Representation Assessments
Get PDFThis study aims to analyze students' conceptions of reaction rate topics using the three-tier multi-representation test. Based on the characteristics of reaction rates concepts that involve the understanding of multiple representations, it is essential to analyze student conceptions that include multiple representations, namely macroscopic, microscopic, and symbolic. A three-tier diagnostic test can be done to assess students' conceptions, with the questions given in the first tier presented with macroscopic, microscopic, or symbolic representations according to the characteristics of the concept in question. This research uses a descriptive quantitative method conducted at Madrasah Aliyah Negeri 2 in Palu City, Central Sulawesi. The subjects of this study were 50 students consisting of 28 female students and 22 male students. It was determined by random sampling technique. Instrumentation used a three-tier representation test with 15 multiple-choice questions. Validation of instruments showed that the questions were feasible and fell into the high category. The findings reveal that only 29 % of students know the concept, categorized as low. Additionally, 40 % of students were identified as having misconceptions, placing them within the medium category, while 31 % of students exhibited not knowing the concept, also classified in the medium category. Symbolic representation emerged as the most challenging representation for students, with 35 % failing to comprehend it, categorized as medium. Furthermore, among students with misconceptions, symbolic and macroscopic representations were the most problematic, collectively accounting for 34 %, also classified as medium. These results underscore the need for targeted instructional strategies to address specific areas of difficulty and improve overall conceptual understanding
Cytotoxicity Test of Bandotan Herbal Ethanol Extract (Ageratum conyzoides L.) Using the Brine Shrimp Lethality Test (BSLT) Method
Get PDFCytotoxic activity is a process that can induce cell death. One of the plants that has cytotoxic properties is bandotan (Ageratum conyzoides L.). The purpose of this study was to identify the class of secondary metabolites present in the ethanol extract of Bandotan herb and to evaluate its cytotoxicity by determining the LC50 value using the Brine Shrimp Lethality Test (BSLT) method. This research includes phytochemical screening and cytotoxicity testing of an ethanol extract of Herba bandotan using the BSLT method. BSLT is the first method for cytotoxicity testing using Artemia salina Leach larvae at the nauplii stage. Used in the BSLT method because it has similar responses with mammals, namely DNA-dependent RNA polymerase in Artemia salina Leach, similar to DNA-dependent RNA polymerase in mammals. By phytochemical screening, the secondary metabolites in Herba Bandotan (Ageratum conyzoides L.) are alkaloids, flavonoids, saponins, steroids, and tannins. Based on the results of the cytotoxicity test using the BSLT method, it shows that the ethanol extract of Herba bandotan (Ageratum conyzoides L.) has the potential to be anti-cancer because it has an LC50 value of 255.1915 g / mL, which is included in the toxic category and has the potential to be anti-cancer. Potential as an anticancer agent in the BSLT test if it has an LC50 value < 1000 µg / mL
Effect of Solvent Differences on Flavonoid Levels and Antioxidant Activity of Hass Avocado Peel (Persea Americana Hass)
Get PDFThe Hass avocado fruit (Persea Americana Hass) comes from Australia. The color of the Hass avocado skin when it is still raw is green, and when it is ripe, it is black. This study aims to see the effect of different solvents in determining the levels of flavonoids and the antioxidant activity of Hass avocado peel extract. Determination of flavonoid levels using UV-Vis spectrophotometry and for antioxidant activity using 2,2-diphenyl-1-pikrihydrazyl (DPPH) as a source of free radicals, and vitamin C as a positive control, and UV-Vis spectrophotometry to measure the absorbance of Hass avocado peel extract. The results showed that the flavonoid content in the ethanol extract of avocado peel was 2.078 mg/100 mg extract, and for the methanol extract of Hass avocado peel was 1.995 mg/100 mg extract. For the antioxidant activity test, the IC50 value of the ethanol extract of avocado peel was 134.181 mg/L, while the IC50 value of vitamin C was 19.815 mg/L. For the methanol extract of Hass avocado rind, the IC50 value was 149.611 mg/L, while for vitamin C, the IC50 value was 37.093 mg/L. Ethanol extract and methanol extract of Hass avocado peel (Persea Americana hass) are classified as moderately strong antioxidants based on IC50 values