Indonesian Journal of Chemical Analysis (IJCA)

The Identification of Acetic Acid-Ethanol Mixture Using Gas Sensor Array and Ensemble Regression

2023-10-26T14:08:35+00:00

Identification of acetic acid-ethanol mixtures using a commercial gas sensor array equipped with ensemble regression has been carried out. The gas sensor analysis was simple, rapid, and fast since it did not require any sample preparation. A quantitative analysis of the acetic acid-ethanol mixture was carried out to determine the sensitivity and selectivity of the sensor in distinguishing the concentration of the acetic acid and ethanol mixture. This study focuses on the coefficient of determination of 80% of the calibration data set and recovery of 20% of the testing data set. The models showed excellent performance,specifically, the Bagging and Random Forest r² for the ethanol calibration data reached 0.91 and 0.94, respectively. The corresponding ethanol test recoveries were 99.95% and 97.84%, indicating the robustness of the model in accurately predicting ethanol concentration. Acetic acid test recoveries were 100.56% and 101.38% with r²of 0.89 and 0.93 for Bagging and Random Forest regression, respectively. Hence, the commercial gas sensor array equipped with ensemble regression can be applied to the quantification of the acetic acid – ethanol mixture and demonstrate opportunities for the practical use of this gas sensor array in analyzing real samples, i.e. human breath or environmental monitoring samples.

Adsorption of Cadmium (II) Ions Using Cassava Peel Activated Carbon: Study of Adsorption Kinetics, Isotherms and Thermodynamics

2024-01-12T02:06:26+00:00

Heavy metals Cd²⁺ is a dangerous pollutant of water and ecological systems if it is above the quality standard threshold. Cassava peel has a fairly high carbon element content, namely 59,31%, so it can be used as an activated carbon to break down Cd²⁺ metals ions in water. This research aims to determine kinetic modeling and adsorption isotherms of Cd²⁺ ions using CPAC activated by H₃PO₄, determine the optimum pH and temperature conditions for Cd²⁺ ion adsorption and determine the adsorption capacity of Cd²⁺ ions using CPAC activated by H₃PO₄. CPAC is made through a carbonization process at a temperature of 500 °C for 1 hour. Next, it was impregnated with H3PO4 at a concentration of 30 % with a ratio of 1:5 (w/w) for 24 hours and physically activated at a temperature of 600 °C for 1 hour. Based on research, kinetic modeling and adsorption isotherms of Cd²⁺ ions using CPAC activated by H₃PO₄ following Pseudo-Second-Order (PSO) kinetic modeling and Freundlich isotherm, the optimum pH and temperature conditions for Cd2+ ion adsorption were obtained at pH 5 and temperature 25 °C. Thermodynamic parameters such as Gibbs energy (∆G°), enthalpy (∆H°), and entropy (∆S°), have been evaluated and indicate physical, spontaneou, and exothermic adsorption processes. The adsorption capacity of Cd²⁺ ions using CPAC activated by H₃PO₄is 5.2219 mg/g.

Adsorption of Remazol Blue And Indigosol Yellow Mixed Dyes Using Bidara Arab Leaves (Ziziphus spina-christi)

2023-10-14T00:57:53+00:00

In this study, the adsorption of Remazol Blue and Indigosol Yellow using Bidara Arab leaves (Ziziphus spina-christi) as adsorbents was investigated through batch adsorption. The experimental parameters included contact time, adsorbent mass, initial concentrations, and pH. UV-Vis spectrophotometer was employed to measure the adsorption results at the maximum wavelength of each dye. The research was conducted in triplicate, and a t-test, "Paired Two Sample for Means", with a standard deviation <2% was employed for statistical analysis. Optimal adsorption conditions were achieved at a contact time of 45 minutes, an adsorbent mass of 45 mg, an initial concentration of 30 ppm, and a pH of 3. The results indicated that Bidara Arab leaves effectively reduced the concentration of the mixed dyes with %decoloration up to 99,79% on Remazol Blue and 99,50% on Indigosol Yellow.

Green-AgNPs modified membrane for monitoring mercury ions in cosmetic sample using pre-concentration assisted voltammetry technique

2024-03-09T13:13:48+00:00

The carcinogenic and teratogenic properties of mercury have driven the necessity for the development of highly sensitive methods capable of detecting even trace amounts of the element. In response to this need, an analysis technique has been established for mercury ions, employing preconcentration methods utilizing filter paper modified by silver nanoparticles (AgNPs) and 3-Amino propyl trimethoxy silane (APTMS). This method allows for the detection of mercury ions through the voltammetry technique, ensuring accurate and reliable results. Upon conducting analyses using this method, it was found that the tested cosmetic samples were free from Hg²⁺ ions, indicating the absence of mercury contamination in the cosmetics under investigation. The correlation coefficient derived from the graph of the analysis results stands at an impressive value of 0.9976, affirming the strong relationship between the measured concentrations and the actual mercury content. Additionally, the method demonstrates excellent sensitivity, as evidenced by the low limit of detection (LOD) value of 0.0483 mM and the limit of quantification (LOQ) value of 0.1611 mM.

Determination of Ethanol in Vinegar and Beverage by Gas Chromatography: A Validated Method for Halal Verification

2024-02-18T13:31:18+00:00

Validation of the method for determining ethanol in vinegar and beverages has been carried out in the linearity range of 0.05-1% using GC-FID. This research was carried out using an internal standard solution and without an internal standard solution. The research aims to validate the linearity of ethanol determination at low concentration levels. This validation is useful to ensure that the ethanol test method in the sample can be detected at low concentration levels. In the halal authentication process, the maximum limit for ethanol content is 5%. The method validation results confirm that in the concentration range 0.05-1% it has good linearity with a correlation coefficient (R) without the addition of internal standards and with the addition of standard solutions being 0.9972 (R²=0.9943) and 0.9952 (R²=0.9905). The results of the analysis of variance (ANOVA) test with a 95% confidence interval and 9 degrees of freedom F-count (0.0141) < F-critical (0.3146) show that the range 0.05-1% corresponds to the limit of linearity. The results of the ANOVA test with a 95% confidence interval with df=6 show the F-test value (0.0879) < F-critical (0.2334) indicating that the two proposed methods have high precision and no significant differences. Both methods also have high accuracy and no significant differences in accuracy as shown by the results of the ANOVA test with a 95% confidence interval and degrees of freedom = 6 showing the F-test value (1.5204) < F-critical (4.2839). It is recommended that the results of this validation be useful in the halal verification process for vinegar and beverage products.

Implementing Biodigester Technology for Sustainable Waste Management in Mojokerto City, Indonesia

2023-12-13T02:59:47+00:00

Mojokerto City, located in East Java, grapples with a steadily rising waste generation trend accentuated by the COVID-19 pandemic. Drawing data from the National Waste Management Information System (SIPSN) and supplemented with an exhaustive literature review, this study scrutinizes the potential of biodigester technology as a solution to this mounting challenge. Mojokerto's waste, consistent in its composition from 2019 to 2022, is dominated by food waste, making it an ideal candidate for biodigester intervention. The study revealed that existing biodigester facilities in Mojokerto vary in their waste reduction efficiencies yet collectively demonstrate the viability of converting food waste to energy. For instance, the TPS 3R Magersari Berseri facility showcased an impressive waste reduction rate of 85.0%, processing 62.05 tons out of 73 tons of waste received annually. Comparative analyses of other facilities like TPS 3R Pulorejo "Cahaya Berseri" and TPS 3R Muria Berseri were also conducted, revealing varying degrees of efficiency. These facilities underscore the potential of biodigester technology in managing the rising tide of waste and contributing to sustainable energy generation. The findings of this study also call for increased awareness about food conservation, improved waste segregation at the source, and the promotion of composting and other organic waste processing methods, thereby optimizing the overall efficiency of waste management in the city.

Detection of Adulterants Metanil Yellow in Turmeric Powder Using Fourier Transform Infrared (FTIR) Spectroscopy Combined with Chemometrics OPLS-DA and PLS

2024-03-01T07:06:05+00:00

Turmeric powder (Curcuma longa L.) is often used for food coloring and flavoring. The high demand for turmeric powder has led to adulteration, one of which is metanil yellow. This study aims to detect metanil yellow dye in turmeric powder using Infrared Spectroscopy (FT-IR) and Chemometrics. The chemometrics model was built by preparing turmeric powder and metanil yellow in the concentration range of 0-50% (w/w). Data was processed using multivariate calibration using OPLS-DA (Orthogonal Partial Least Squares Discriminant Analysis) and PLS (Partial Last Square). The results obtained from OPLS-DA processing of market samples 1 and 2 are estimated to be pure turmeric powder, and samples 3 to 10 are adulterated. From the PLS results, the best calibration model was obtained at wave numbers 1199-539 cm^-1 with R² values for calibration and validation of 0.9967 and 0.9970, respectively, with RMSEC of 2.48 and RMSEP of 6.35. The PLS results showed that in sample 3 containing metanil yellow, in samples 4 to 10, no metanil yellow was detected. The ingredients added were not metanil yellow. It was concluded that FTIR combined with chemometrics could detect the metanil yellow in turmeric powder.

In Vitro Activity of Ethanol Extract of Rimbang Fruit (Solanum ferox) as an Active Ingredient in Sunscreen Preparations

2024-01-10T04:19:09+00:00

Solanum ferox is a typical Central Kalimantan plant widely used by Dayak’s community as a vegetable. The study aims to determine the ethanol extract of sour eggplant activities by measuring its SPF in vitro and identifying secondary metabolite contents. The sour eggplant is extracted by maceration using 96% ethanol solvent and then bound with an evaporator. The secondary metabolite groups of ethanol extract were identified using phytochemical screening. The identification results indicate the presence of flavonoid, terpenoid, steroid, and phenolic compounds. Then, the ethanol extract was fractionated with a water solvent, and its functional cluster was identified using the IR spectrum. IR spectral identification results indicate the presence of OH, C-O, C=C olefin, C -O ether, and aliphatic CH functional groups. (CH₂ and CH₃) SPF values were determined by measuring the absorption of ethanol and water extracts in vitro using UV-Vis spectrophotometry at UV-B wavelengths of 290-320 nm. In vitro testing has been conducted as a preliminary test in developing a sunscreen product (active substance). The SPF values of ethanol extract and water from weighted fruit extract in sequence are 40 and 23 at a 10% concentration with ultra-category.

The Role of Zeolite (Microporous Crystalline Aluminosilicates) In Catalytic Pyrolysis of Waste High- and Low-Density Polyethylene Bags for Production of Fuel and Chemicals: A Review

2024-03-09T13:08:57+00:00

This review provides a state-of-the-art summary of the role which zeolite plays as a catalyst via pyrolysis as a way of recovering fuels and chemicals from waste high and or low density polyethylene bags. It also highlighted the two types of zeolite (natural or synthetic) which are used as a two-stage pyrolysis−catalysis in giving a free waxing product to pure fuel and chemicals which can be subjected to further analyzing and or upgrading. As yield of oil/wax decreased with the addition of a zeolite as catalyst from 44 and 51 wt.%, (depending on the waste high density polyethylene “HDPE” or low density polyethylene bags “LDPE” and other factors). However, the composition of the pyrolysis−catalysis oils significantly increased in aromatic hydrocarbon content accordingly. In addition, the composition of the oils shifted from high molecular weight hydrocarbons (C₁₆₊) to fuel range hydrocarbons (C₅−C₁₅), with a high content of single-ring aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylenes, and styrene. This process shows great potential for production of fuels or chemicals, and also addresses the urgent issue of waste HDPE and or LDPE disposal.

Detection of Microplastics and Heavy Metals in Famous Edible Molluscs in Can Gio Biosphere Reserve of Vietnam

2023-12-14T03:32:39+00:00

Can Gio, designated in 2000, is the first Biosphere Reserve of Vietnam. In recent years, local agriculture, tourism, households, nearby industrial zones, and maritime transport have released substances into rivers flowing through Can Gio Mangrove to the East Sea and transported into creatures. This study aims to investigate microplastics and heavy metals in the famous seafood of Can Gio. A Raman microscope was used to identify microplastics from the tissue of oysters, grease snails, and clams after enzymatic treatment with trypsin. Heavy metals were quantified with ICP-MS after acidic treatment. As a result, microplastics were found in almost all samples, even up to 10 in a random individual of bivalve. Fibers dominated, especially from 30 to 150 µm long. The metal with the highest content was zinc, followed by copper, especially in oysters. Non-essential metals were also present in the soft tissue in the order As > Pb > Cd. The accumulation of metals in Can Gio’s molluscs was generally lower than in other regions and still in the allowed range for consumption of Vietnamese Standard. Although there have not been any Vietnamese regulations on the permissible level of microplastics for consumption, regular seafood intake will increase the risk of chronic poisoning and unknown disorders caused by the accumulation of microplastics and heavy metals.