Phosphorus Analysis in Meat using UV-Vis Spectrophotometry with SnCl2 and Hydrazine Sulfate Reduction

This study aimed to optimize phosphorus analysis in meat using a molybdenum blue reaction involving SnCl2 and hydrazine sulfate as reducing agents to establish the most effective conditions for phosphorus detection. Meat, an essential source of nutrients like phosphorus, plays a vital role in human health, particularly bone and tooth strength. However, overconsumption of phosphorus can lead to health issues such as hyperphosphatemia, making regular monitoring of phosphorus levels in food necessary. The experiment used SnCl2 and hydrazine sulfate under varying acidic conditions to produce a stable blue complex indicative of phosphorus presence. The complex exhibited maximum absorbance in the 689–729 nm wavelength range. Validation of the method showed high linearity with R2 values of 0.9983 and 0.9984 for SnCl2 and hydrazine sulfate, respectively. The molar absorptivity for SnCl2 was 2.093 x 105 L mol-1 cm-1 and 7.92 x 104 L mol-1 cm-1 for hydrazine sulfate. Detection and quantification limits were established, and the %RSD values in each sample ranged from 1.08% to 1.93%, conforming to standard requirements. Upon analysis of meat samples, including duck, chicken, and beef, the phosphorus levels did not meet the Indonesian Nutritionist Association (PERSAGI) standards. This result emphasizes the need for regular phosphorus analysis in meat products to prevent health risks associated with excessive phosphorus intake, such as hyperphosphatemia

Biosynthesis of Poly Acrylic Acid (PAA) Modified Silver Nanoparticles, Using Basil Leaf Extract (Ocimum basilicum L.) for Heavy Metal Detection

This study focused on characterizing synthesized silver nanoparticles (AgNPs) and evaluating their efficacy as colorimetric detectors for heavy metal ions. The synthesis employed a bottom-up approach, using AgNO3 as a precursor, reduced by secondary metabolites in basil leaf extract, enhanced with Polyacrylic acid (PAA). Basil leaves were chosen for their rich content of secondary metabolites like phytosterols, alkaloids, phenolic compounds, tannins, lignin, starch, saponins, flavonoids, terpenoids, and anthraquinones, crucial in reducing silver ions. Incorporating basil leaf extract as a bioreactor and adding PAA to increase stability and selectivity towards metal ions are innovative aspects of this research. The optimal AgNP composition was attained with a 0.7 mL basil leaf extract to 10 mL AgNO3 ratio plus 2% PAA. The AgNP formation was indicated by a color change from yellow to brownish, with a Surface Plasmon Resonance (SPR) peak at 418 nm. Characterization via Fourier Transform Infrared Spectroscopy (FTIR) revealed hydroxyl (-OH) and carbonyl (C=O) functional groups aiding in silver ion reduction. Particle Size Analysis (PSA) showed AgNPs of 72.3 nm size, with a polydispersity index of 0.504. Colorimetric detection tests were conducted on Cu(II), Pb(II), Cd(II), Zn(II), and Mn(II) ions. AgNPs exhibited high reactivity towards Cu2+, changing color from brownish to clear white within a minute upon Cu2+ addition, unlike Cd2+, Mn2+, Zn2+, and Pb2+, which showed negligible changes. This indicates a heightened sensitivity of AgNPs to Cu2+ ions. Such a colorimetric sensor could be instrumental in detecting heavy metals in drinking water, showcasing the potential application of AgNPs in environmental monitoring

Integration of Palembang Cultural Products in the Learning of Electrolyte and Nonelectrolyte Solutions: An Ethnopedagogical Approach

Meaningful chemistry learning can occur if students can connect new knowledge with previously owned knowledge. It is challenging for teachers to carry out a meaningful learning process by linking different students' cultural backgrounds and characters. This study used an ethnopedagogical approach in studying electrolyte and nonelectrolyte solution materials using Palembang cultural products that contain chemical aspects, namely (1) cuko (gravy) pempek contains vinegar which is a weak electrolyte solution, (2) kuah (sauce) pindang contains citric and tartaric acids, which are weak electrolytes, and (3) in the process of making Batik Palembang using caustic soda for coloring which is an example of a strong electrolyte. This research aimed to develop creative and meaningful learning methods to improve the quality of learning. This research was conducted in class X IPA 1 SMA Negeri 5 Palembang in January-March 2021. Qualitative descriptive methods and ethnopedagogical approaches were used in this research. It was carried out through five stages, namely Self Identification by conducting interviews to determine cultural background, Content Integration by providing ethnochemical articles, Collaboration by doing practicum, Dialogue by conducting discussions, and Reflection by filling in reflective journals. Based on this research, it can be seen that students can connect chemical concepts with local wisdom through cultural products. Students do not find it challenging to understand electrolyte and nonelectrolyte solution material because they use cultural products closely related to everyday life

Effectiveness of Using Zn Powder and Spongy Cadmium As Reductor on Free Nitrite and Nitrate Analysis Method Validation in Bread Samples by UV-Vis Spectrophotometry

This research had been carried out on the analysis of nitrite and nitrate in bread by UV-Vis spectrophotometry through a diazotization reaction. The research began by determining the optimum conditions for nitrite analysis while nitrate needs to be reduced using Zn powder or spongy cadmium so it can be analyzed by UV-Vis spectrophotometry. Ionic interference could affect nitrite analysis using UV-Vis spectrophotometry, then both nitrite and nitrate analysis methods were validated based on the method validation parameters. The diazotization reaction produced an azo compound which have λmax 546 nm. The validation results showed that the linearity of nitrite and nitrate has R2 = 0.9990 in the range 0-1 mg L-1 with a molar absorptivity value for nitrite without a reduction process was 3.37 × 104 L mol-1 cm-1, meanwhile 2.91 × 104 L mol-1 cm-1 and 3.83 × 104 L mol-1 cm-1 was shown for the reduced nitrite of Zn powder and spongy cadmium. The detection limits were 4.29 × 10-3, 9.34 × 10-3 ,and 7.58 × 10-3 mg L-1 .The %RSD results were 0.31-1.83% with recovery percentage of nitrite and nitrate in the range of 83.2-104.4%. The strongest ionic interference was shown by Fe2+ and Fe3+ ions at concentrations < 10 mg L-1. WHO has confirmed that the daily intake for nitrate that is acceptable to be consumed by human is 0-3.7 mg/kg

Pelaksanaan Model Pembelajaran Problem Based Learning (Pbl) Pada Materi Redoks Kelas X SMA Negeri 5 Surakarta Tahun Pelajaran 2013/2014

Tujuan penelitian adalah untuk mengetahui keterlaksanaan pembelajaran dan efektivitas pembelajaran melalui pembelajaran berbasis masalah pada materi redoks kelas X SMA Negeri 5 Surakarta tahun pelajaran 2013/2014. Penelitian ini merupakan penelitian deskriptif. Subyek penelitian adalah peserta didik kelas X MIA-3. Sumber data berasal dari guru dan peserta didik yang meliputi data keterlaksanaan pembelajaran dan keefektivan pembelajaran. Teknik pengumpulan data menggunakan teknik tes yang terdiri dari tes tulis dan teknik non tes yang terdiri dari observasi, wawancara, angket, dan dokumentasi/arsip. Teknik analisis data menggunakan analisis deskriptif kualitatif. Berdasarkan hasil penelitian dapat disimpulkan bahwa pembelajaran berbasis masalah dapat dilaksanakan pada materi reaksi redoks kelas X SMA Negeri 5 Surakarta tahun pelajaran 2013/2014. Hal ini dilihat dari ketercapaian target pembelajaran yaitu; terlaksananya sintak pembelajaran berbasis masalah; 86,29% peserta didik memiliki kompetensi sikap baik pada pembelajaran langsung; dan kesesuaian waktu pelaksanaan pembelajaran berbasis masalah dengan alokasi waktu yang ditentukan pada silabus pembelajaran. Pembelajaran berbasis masalah juga efektif diterapkan pada materi reaksi redoks kelas X SMA Negeri 5 Surakarta tahun pelajaran 2013/2014. Hal ini dilihat dari ketercapaian target pembelajaran yaitu; 76,25% peserta didik memiliki aktivitas belajar tinggi; 81,25% peserta didik mencapai KKM materi reaksi redoks; dan 90,63% peserta didik memiliki sikap sangat baik melalui penilaian angket serta 82,29% peserta didik memiliki sikap baik melalui penilaian observasi

PELAKSANAAN MODEL PEMBELAJARAN PROBLEM BASED LEARNING (PBL) PADA MATERI REDOKS KELAS X SMA NEGERI 5 SURAKARTA TAHUN PELAJARAN 2013/2014

Tujuan penelitian adalah untuk mengetahui keterlaksanaan pembelajaran dan efektivitas pembelajaran melalui pembelajaran berbasis masalah pada materi redoks kelas X SMA Negeri 5 Surakarta tahun pelajaran 2013/2014. Penelitian ini merupakan penelitian deskriptif. Subyek penelitian adalah peserta didik kelas X MIA-3. Sumber data berasal dari guru dan peserta didik yang meliputi data keterlaksanaan pembelajaran dan keefektivan pembelajaran. Teknik pengumpulan data menggunakan teknik tes yang terdiri dari tes tulis dan teknik non tes yang terdiri dari observasi, wawancara, angket, dan dokumentasi/arsip. Teknik analisis data menggunakan analisis deskriptif kualitatif. Berdasarkan hasil penelitian dapat disimpulkan bahwa pembelajaran berbasis masalah dapat dilaksanakan pada materi reaksi redoks kelas X SMA Negeri 5 Surakarta tahun pelajaran 2013/2014. Hal ini dilihat dari ketercapaian target pembelajaran yaitu; terlaksananya sintak pembelajaran berbasis masalah; 86,29% peserta didik memiliki kompetensi sikap baik pada pembelajaran langsung; dan kesesuaian waktu pelaksanaan pembelajaran berbasis masalah dengan alokasi waktu yang ditentukan pada silabus pembelajaran. Pembelajaran berbasis masalah juga efektif diterapkan pada materi reaksi redoks kelas X SMA Negeri 5 Surakarta tahun pelajaran 2013/2014. Hal ini dilihat dari ketercapaian target pembelajaran yaitu;  76,25% peserta didik memiliki aktivitas belajar tinggi; 81,25% peserta didik mencapai KKM materi reaksi redoks; dan 90,63% peserta didik memiliki sikap sangat baik melalui penilaian angket serta 82,29% peserta didik memiliki sikap baik melalui penilaian observasi. Kata Kunci:Pembelajaran berbasis masalah, reaksi redoks, proses belajar, efektivitas pembelajaran, pretasi belaja

Synthesis of Modified Polyvinyl Pyrrolidone (PVP) Silver Nanoparticles Using Soursop (Annona muricata Linn) Leaf Extract and Its Application as a Heavy Metal Colorimetric Sensor

This study aims to analyze the characteristics and performance of silver nanoparticles (AgNP) synthesized using soursop leaf extract bioreductor modified with the addition of polyvinyl pyrrolidone (PVP) stabilizer as a colorimetric sensor for heavy metal ions. The synthesis of silver nanoparticles was carried out by reducing AgNO3 using soursop leaf extract (Annona muricata Linn) bioreductor modified with the addition of PVP as stabilizer. The results showed that the optimum synthesis volume ratio of AgNP synthesis was 0.7 mL of soursop leaf extract: 10 mL AgNO3 with the addition of 3% PVP stabilizer. The formation of AgNP was characterized by a change in the color of the solution from yellow to brownish with a surface plasmon resonance peak at a maximum wavelength of 438 nm. Fourier-transform infrared spectroscopy studies showed hydroxyl groups (-OH) and carbonyl groups (C=O) play a role in the reduction process of silver ions. Particle size analysis results demonstrated an average particle size of 71.5 nm with a polydispersity index value of 0.364. The results of the colorimetric analysis showed that the synthesized AgNPs proved to be highly selective towards Cu metal ions