Tanpa disadari, setiap siswa senantiasa memiliki miskonsepsi pada materi kimia. Diganosa ‎miskonsepsi sejak dini sangat penting untuk menghentikan miskonsepsi agar tidak berpemngaruh ‎pada konsepsi beikutnya dan hasil belajar yang buru. Penelitian deskriptif ini bertujuan untuk ‎mendiagnosa miskonsepsi siswa SMA Negeri 1 Telaga Gorontalo pada materi termokimia dengan ‎cara tes diagnostik pilihan ganda dua tingkat. Sebanyak 25 soal pilihan ganda tersebut telah valid ‎dan reliabel serta diujikan pada 65 siswa SMA tersebut. Hasil yang diperoleh bahwa jumlah siswa ‎yang mengalami miskonsepsi sangat rendah, rendah, dan sedang masing-masing adalah 60 (92%), ‎‎3 (5%), dan 2 (3%). Sementara, miskonsepsi dengan kategori tinggi dan sangat tinggi tidak ‎ditemukan. Indikator materi yang mengalami miskonsepsi banyak adalah soal tentang teori atau ‎konsep dibandingkan dengan perhitungan. Teori tersebut tentnag membedakan jenis reaksi ‎eksoterm dan endoterm dan membedakan macam-macam perubahan entalpi molar. Hal ini ‎mengindikasikan bahwa siswa lebih banyak menghafal daripada memahami materi termokimia. ‎Hasil diagnosa ini dapat dijadikan acuan untuk pembelajran termokimia agar guru dapat ‎menerapkan cara yang tepat dalam pembelajaran

Tombili plant (Caesalpinia bonducella) belongs to the family of Fabaceae. The seed extract of tombili has been empirically used as a traditional medicine. The purpose of this research was to fractionate tombili seed extract and test their antioxidant and cholesterol lowering activities. Extraction was made into fractions using n-hexane, ethyl acetate, and methanol as a solvent. The chemical compound of the ethyl acetate fraction was analyzed using liquid chromatography-mass spectrometry (LC-MS/MS). Antioxidant activity was tested using the DPPH method. The highest antioxidant activity was shown in ethyl acetate fraction with an IC50 value of 86.153 μg/mL. The second was the methanol fraction with an IC50 value of 94.053 μg/mL, and the third was the n-hexane fraction with an IC50 value of 100.933 μg/mL. The cholesterol lowering activity analysis showed that all fractions could inhibit cholesterol. The highest anti-cholesterol activity shown in ethyl acetate fraction with the concentration of 600 μg/mL can inhibit 81.5% of the cholesterol activity. The LC-MS/MS analysis showed that the ethyl acetate fraction contained glucoside, homoplantaginin, and vernolic acid compounds.

Caesalpinia bonducella, known as ‘tombili’ belongs to the family of Fabaceae. Tombili has been empirically used as traditional medicine. In a previous study, phytochemical screening showed that tombili seed contained alkaloid, flavonoid, terpenoid, and tannin compounds. This research aimed to isolate an antioxidant compound from tombili seed extract. Fractionated using n-hexane, ethyl acetate, and methanol as a solvent. All fractions were tested for their antioxidant potential. The ethyl acetate fraction gave a better antioxidant potential (IC50 86.153±4.22 ppm) than it has purified. Characterization of an isolated compound using various spectroscopies data, including UV, FTIR, 1D-NMR, 2D-NMR, and LCMS/MS. The structure of the isolated compound was suggested as 7- (β-DGlucopyranosyloxy) 5-hydroxy-2-(4-hydroxyphenyl)-6-methoxy-4H-1-benzopyran-4-one (homoplantaginin). The IC50 value

Tinospora crispa is a plant of the Menispermaceae family which is one of the endemic plants in Indonesia, commonly called as Brotowali. T. crispa is traditionally used to treat diabetes, rheumatism, sinusitis and fever. The purpose of this study was to determine the molecular structures of isolated compound of methanol fraction from T. crispa stem bark. Extraction using maceration method with n-hexane, ethyl acetate and methanol as solvents. The structures of compounds were elucidated with spectroscopic data ( 1 H, 13 C, DEPT 135º, HMBC, HMQC, 1 H-1 H COSY NMR, IR) and MS as well as compared with previously reported spectral data. The structure of isolated compound was finally identified as 24(R)methylcholesta-5-en-3β-ol (campesterol) by the compared of several physical and spectral data with the literature. In previously study, campesterol have antiangiogenic and anticholesterol activities.

Penelitian ini bertujuan untuk mengisolasi dan mengidentifikasi senyawa metabolit sekunder ekstrak etil asetat dari daun sambiloto. Isolasi tersebut dilakukan melalui tahap maserasi, fraksinasi, dan kromatografi. Identifikasi ekstrak tersebut dan isolatnya dilakukan dengan cara uji fitokimia, spektrofotometer-UV Vis, dan IR. Daun sambiloto kering sebanyak 633 gram dimaserasi dengan metanol selama 3×24 jam, dan diperoleh ekstrak kental metanol setelah melalui proses evaporasi. Ekstrak tersebut difraksinasi berturut-turut dengan n-heksana dan etil asetat untuk menghasilkan ekstrak kental etil asetat sebanyak 21,99 gram. Kemudian, ekstrak kental etil asetat dipisahkan dengan kromatografi kolom dan diuji kemurniannya dengan KLT dan diperoleh isolat murni yang berupa kristal putih dengan berat 126,3 mg. Hasil uji fitokimia ekstrak etil asetat menunjukkan bahwa daun sambiloto mengandung flavanoid dan triterpenoid. Sementara, isolat murni yang dihasilkan adalah senyawa triterpenoid. Hasil pengukuran spektrofotometer UV-Vis menunjukkan adanya 2 pita serapan pada panjang gelombang 278 dan 202, dan hasil pengukuran spektrofotometer IR adanya gugus fungsi O-H alkohol pada bilangan gelombang 3426.5 cm-1, C-H alifatik pada bilangan gelombang 2918.1 cm-1 dan 1463.3 cm-1, C=O pada bilangan gelombang 1640.6 cm-1, C=C alkena pada bilangan gelombang 1559.2 cm-1, C-H pada bilangan gelombang 802.5 cm-1 dan 886.4 cm-1, dan C-O alkohol pada bilangan gelombang 1099.6 cm-1 yang menandakan bahwa isolat merupakan suatu senyawa golongan triterpenoid

rhinoceros Linn) using Mannich's reaction and Claisen rearrangement has been synthesized. The synthesis of compounds includes five phases: synthesis, separation, purification and structure determination. The pure compounds produced from each stage of further synthesis are characterised using mass spectroscopy and infra-red spectroscopy. 4-Methiloctanoic acid synthesis products and ethyl-4-methyloktanoat pheromone aggregation kumbang badak (Oryctes rhinoceros Linn) use Mannich reaction and Claisen rearrangement 50.53% and 63.69% respectively

The purpose of these study is to determine the effect of active compound from tombili seed extract as a vegetable pesticide in the prevention of soil pest in rice plants. The method of these researches is isolation to obtain pure isolates, characterization by using infrared spectrophotometer (IR) and UV-VIS spectrophotometer then following biological test. The isolates obtained were tested positive for phytochemical containing alkaloid compounds and characterized as amorphous crystals. Identification of IR spectrophotometer generate a functioning -NH wave group of the wavelengths region of 3423.4 cm-1, bend C-N at wave number 1242.1 cm-1, C-H stretch at wave number 2925.8 and 2854.5 cm-1, bend C-H at 1475 wave numbers 1540 cm-1, carbonyl group (C = O) at the 1720.4 cm-1 wave number which is probably an alkaloid compound. The UV-VIS spectrophotometer results in a maximum absorption at 209.9 nm wavelengths indicated the presence of double bonds between the C = O functional group suspected as a result of the successive electronic transitions to n-π * and n-σ *. The result of biological test showed that methanol extracts of tombili seed can be used as a vegetable pesticide in pest prevention on rice plants, the most effective concentration used in this biological test is at 0.1% concentration, with very high effectiveness in eradicating pest on rice plants.

The purpose of this study was to determine and analyze the levels of leadcontained in the water and sediments of the Rumbia River. This research was conducted in a quantitative manner. Lead levels were measured using Atomic Absorption Spectrophotometer (SSA) of Simatzu AA 500. The results showed that the leadcontent in Rumbia River water for point A1 was undetectable whereas point 2 and 3 were 0.001 mg/kg. In sediments, at point A1 is 1.8 mg/kg and at points 2 and 3 were 0.9 mg/kg. The level of Pb in Rumbia River water is still below the water quality standard limit for marine biota determined by the Ministry of Environment No. 51 of 2004. Similarly, lead levels in sediments are below the threshold standard for sediment quality based on sediment quality guidelines for metals and associated levels of concern to be used in doing assessments of sediment quality. In general, it can be said that the concentration of lead in the Rumbia River is still at a harmless level. However, socio-economic conditions that continue to change over time can cause changes in the level of water pollution. So there needs to be an effort and public awareness in maintaining the occurrence of increased levels of pollutants in the Rumbia River.