Silica gel (SG) is one of common adsorbent on solid phase extraction for preconcentration. Due to the low selectivity and effectiveness of adsorption to metal ions, SG should be modified. The SG was modified with d-glycine (Si-Gly) using 3-aminopropyltrimethoxysilane and glutaraldehyde as a crosslinker. Capability of Si-Gly as adsorbent for cadmium ions (Cd) was investigated using batch adsorption. The result was proved by infrared spectra. The optimum condition of Cd adsorption by the Si-Gly was obtained at pH 5, with 0.3 g of adsorbent and 11 minutes of contact time. The percentage of Cd adsorption at the optimum condition by the Si-Gly (99.34%) which is greater than the SG (89.03%). The maximum adsorption capacity of the Si-Gly is 9.77 mg/g, obtained at 400 mg/L. The Cd(II) adsorption on the SG and the Si-Gly follow the Langmuir isotherm equation.

Biomass, such as wood waste, is one of the resources that can be potentially converted into a carbon product for catalyst applications. In this study, the sulfonated carbon was obtained through the pyrolysis method for wood waste at the temperature of 350°C, which was later sulfonated through the use of  H2SO4 (8N) on the reflux for 4 h. The sulfonated carbon was then analyzed and characterized including its water content, ash content, volatile matter, fixed carbon, iodine adsorption as well as the H+ (acidity) capacity using ammonia adsorptions and functional groups and the Fourier Transform Infra-Red (FTIR) instrument. The catalyst application was carried out during the kempili pulp hydrolysis process using a microwave with the ratio of catalyst to a pulp of 1:1 (5g:5g), with the power conditions of 300, 400, and 600 watt for 3, 5, and 7 min. The results showed that the sulfonated carbon catalyst had water content, volatile matter, ash content, fixed carbon, iodine adsorption as well as the catalyst acidity as much as 3.48%; 11.70%; 4.21%; 84.62%; 690.88 mg/g; and 6.45 mmol/g, respectively with the highest glucose content of 160.83 ppm. The carbon-based catalyst is expected as an alternative catalyst, can be further developed for hydrolysis reactions, and can serve as a green technology product in the future.

Phyllanthus niruri is known as a stone breaker and has some biological activities such as antioxidant, antibacterial, anti-inflammatory, antiviral, immunostimulant, etc. There are two other species related to P. niruri namely P. debilis and P. urinaria. The morphology of the three plants is quite similar so that identification and discrimination of the three species are very crucial to avoid adulteration of P. niruri from the two related species for ensuring the quality, efficacy, authenticity, and safety of its herbal medicinal product. This study aims to develop identification and discrimination method of P. niruri based on thin-layer chromatographic (TLC) fingerprint combined with chemometrics analysis. The result showed that P. niruriprovides a different fingerprint profile compare to P. debilis and P. urinaria. P. niruri has two characteristic bands (Rf 0.71 and 0.77) that could be used for discrimination from P. debilis and P. urinaria. To enhance the discrimination of the three species, we used discriminant analysis with peak area from 13 detected peaks as the variable. From the results obtained, the discriminant analysis showed the separation of each species using the first two discriminant function (DF) with variance for DF-1 = 63.34% and DF-2 = 36.66% in DA plots, which explain 100% of total discriminant factor varianceand correct classification rate is 100%. The developed TLC fingerprint combined with discriminant analysis successfully distinguished three closely related species of Phyllanthus.

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Orthosiphon aristatus, known as kumis kucing in Indonesia, has some biological activity, i.e., as an anti-inflammatory, fever, rheumatism, diabetes, and kidney stone. This plant is also known for being rich in phenolic compounds such as flavonoids. In this study, we would like to compare the antioxidant activity, total phenolics, and flavonoid content from the stems and leaves of Orthosiphon aristatus extracted with water and ethanol by maceration. The yield stem and leaves of the water extract are 12.98-31.28%, and ethanol extract 3.58 - 9.82% (dry basis). The stem and leaves water extract contains a phenolic of 7.82-26.43 (mg GAE/g) and ethanol extract of 2.27-7.84 (mg GAE/g). Water extract Orthosiphon aristatus flavonoid content is 1.23-2.86 (mg EK/g), and ethanol extract is 1.09-3.95 (mg EK/g). The antioxidant activity of ethanol (IC50), extract from leaves was 123.91 (µg/mL) and from stems was 125.50 (µg/mL), while IC50 of water extract from leaves was 114.70 (µg/mL) and from stems was 125.03 (µg/mL). The correlation test result of active compounds using linear regression is phenolic compounds with antioxidants stronger than flavonoids. The qualitative thin-layer chromatography fingerprint analysis showed that ethanol and water extract contained natural sinensetin compounds.