Dwi Siswanta
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara, Yogyakarta 55281, Indonesia

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Detection of Taste Change of Bovine and Goat Milk in Room Ambient Using Electronic Tongue Imam Tazi; Anis Choiriyah; Dwi Siswanta; Kuwat Triyana
Indonesian Journal of Chemistry Vol 17, No 3 (2017)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (449.033 KB) | DOI: 10.22146/ijc.25288

Abstract

An electronic tongue (e-tongue) based on an array of lipid/polymer membranes has been successfully developed for measuring the taste evolution of natural milk. The e-tongue consisted of 16 different lipid/polymer membranes combined with or without a pH sensor. The natural milk of bovine and goat were purchased from the local farming store in Malang-Indonesia. The taste measurement was carried out, from fresh (0 h) to stale (12 h), every two hours under room ambient without any treatment. The responses of the e-tongue were evaluated using a Principal Component Analysis (PCA) and a Linear Discriminant Analysis (LDA). From PCA results, the taste of both milk samples tends to change by time although some groups show a partial overlapping. LDA results show the high precision of the e-tongue in clustering taste evolution. The correctly classified groups after the cross-validation procedure were achieved 95.7 and 87.1% for bovine and goat milk, respectively. The improvement of the classification using LDA was obtained by adding data from a pH sensor of each measurement as 100 and 98.6% for bovine and goat milk, respectively. This work indicates that the lab-made e-tongue may be useful to predict the quality of natural milk for the food industry.
The Physico-Mechanical Properties and Release Kinetics of Eugenol in Chitosan-Alginate Polyelectrolyte Complex Films as Active Food Packaging Baiq Amelia Riyandari; Suherman Suherman; Dwi Siswanta
Indonesian Journal of Chemistry Vol 18, No 1 (2018)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (379.652 KB) | DOI: 10.22146/ijc.26525

Abstract

A study of eugenol release and its kinetics model from chitosan-alginate polyelectrolyte complex (PEC) films has been conducted. Some factors that affected the eugenol release were also studied, including the composition of chitosan-alginate PEC and the concentration of eugenol. The chitosan-alginate-eugenol PEC films were synthesized at pH ± 4.0, then the PEC films were characterized using a Fourier-transform infrared spectroscopy (FTIR) spectrophotometer. An investigation of the films’ properties was also conducted, including morphology analysis using a scanning electron microscope (SEM), differential thermal analysis (DTA) / thermogravimetric analysis (TGA), mechanical strength, transparency testing, water absorption, and water vapor permeability. The release of eugenol was investigated through in vitro assay in ethanol 96% (v/v) for four days, and the concentration of eugenol was measured using an ultraviolet-visible (UV-Vis) spectrophotometer. The characterization of the films using FTIR showed that the formation of PEC occurred through ionic interaction between the amine groups (–NH3+)of the chitosan and the carboxylate groups (–COO–) of the alginate. The result showed that the composition of chitosan-alginate PEC and the concentration of eugenol can affect the release of eugenol from PEC films. A higher concentration of alginate and eugenol could increase the concentration of eugenol that was released from the films. The mechanism for the release of eugenol from chitosan-alginate PEC films followed the Korsmeyer-Peppas model with an n value of < 0.5, which means the release mechanism for eugenol was controlled by a Fickian diffusion process. The antioxidant activity assay of the films using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method resulted in a high radical scavenging activity (RSA) value of 55.99% in four days.
Synthesis and Kinetic Study of the Urea Controlled Release Composite Material: Sodium Lignosulfonate from Isolation of Wood Sawdust-Sodium Alginate-Tapioca Arif Cahyo Imawan; Yehezkiel Steven Kurniawan; Muhammad Fernadi Lukman; Jumina Jumina; Triyono Triyono; Dwi Siswanta
Indonesian Journal of Chemistry Vol 18, No 1 (2018)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (422.693 KB) | DOI: 10.22146/ijc.26597

Abstract

A synthesis and kinetic study of the urea controlled-release composite material based on isolated Na-lignosulfonate, Na-alginate and tapioca was carried out. This experiment’s aims were to isolate Na-lignosulfonate from wood sawdust and to applicate this isolated Na-lignosulfonate, along with tapioca and Na-alginate as urea control release composite material. A kinetic study of urea released from the composite materials was also conducted. Na-lignosulfonate was isolated by Kraft lignin method to give a brown solid yield of 16.92% and was characterized by FT-IR spectrophotometer and SEM-EDX. The composite materials were synthesized by blending urea as the active compound with composite material as the carrier compound. Three types of material were prepared: complete material (A), low-concentration Na-lignosulfonate material (B) and material without tapioca (C). The composite material had a spherical form with 0.79 mm radius and 2.16 mm swollen radius. Urea content inside material was 40.425 mg urea/g material. The urea diffusivity coefficient for material A, B, and C were 7.27 x 10–6; 15.50 x 10–6 and 0.94 x 10–6 m2 h–1, respectively. Modelling analysis showed the experiment obeyed around only 15% of the Korsmeyer–Peppas model, but there was good correlation (80%) with the unsteady-state diffusion model.
Development of C-Arylcalix[4]resorcinarenes and C-Arylcalix[4]pyrogallolarenes as Antioxidant and UV-B Protector Jumina Jumina; Dwi Siswanta; Abdul Karim Zulkarnain; Sugeng Triono; Priatmoko Priatmoko; Emmy Yuanita; Nela Fatmasari; Ikhsan Nursalim
Indonesian Journal of Chemistry Vol 19, No 2 (2019)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (259.651 KB) | DOI: 10.22146/ijc.26868

Abstract

Indonesia is rich with essential oils such as anise and clove leave oils. In respect to explore the potential utilization of these resources, it has been conducted the transformation of p-hydroxybenzaldehyde and vanillin (4-hydroxy-3-methoxy benzaldehyde) respectively derived from anise oil and clove leaves oil to a series of C-arylcalix[4]resorcinarenes and C-arylcalix[4]pyrogallolarene macrocycles. Treatment of these aldehydes with resorcinol in the presence of HCl in absolute ethanol at reflux for 8 h afforded C-4-hydroxyphenylcalix[4]resorcinarene (3a) and C-4-hydroxy-3-methoxy phenyl-calix[4]resorcinarene (3b) in good yields. When the aldehydes were treated with pyrogallol under the similar condition, the products were C-4-hydroxyphenyl calix[4]pyrogallolarene (3c) and C-4-hydroxy-3-methoxyphenylcalix[4]pyrogallolarene (3d) which were also obtained in excellent yields. Treatment of these calix[4]resorcinarenes and calix[4]pyrogallolarenes with cinnamoyl chloride and benzoyl chloride in pyridine afforded the corresponding cinnamate esters and benzoate esters in high yields. The resulted C-arylcalix-[4]resorcinarenes and C-arylcalix[4]pyrogallol arenes were subjected to antioxidant activity test using DPPH method and showed strong activity with IC50 values of 15–80 μg/mL. In terms of the synthesized calix cinnamates, the compounds showed UV-B absorption with SPF values of 15–30 at a concentration of 25 ppm which demonstrate their potential to be applied as a UV-B protector. Furthermore, these compounds were also tested for their photostability on the UV-B region and the results showed that the compounds were still unstable under irradiation for 30 min.
Inhibitive Determination of Hg(II) in Aqueous Solution Using Urease Amperometric Biosensor Dhony Hermanto; Bambang Kuswandi; Dwi Siswanta; Mudasir Mudasir
Indonesian Journal of Chemistry Vol 19, No 3 (2019)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (16.061 KB) | DOI: 10.22146/ijc.40617

Abstract

An amperometric biosensor for the indirect determination of Hg(II) has been developed based on inhibition of urease (EC 3.5.1.5) immobilized into alginate–chitosan polyelectrolyte complexes membrane. The biosensor response was monitored by following the reduction peak of hydrolyzed urea at around -0.15 V. The amperometric biosensor has a dynamic range 40–90 ppb Hg(II) with limit of detection of 66.45 ppb toward Hg(II) ions, repeatability (CV) value of 0.86% and only Ag(I) as the main potential interference. The sensor shows a stable and reproducible response for more than 2 weeks when it stored dry at 4 °C. The analytical results of Hg(II)-spiked water sample showed a good agreement with those obtained by atomic absorption spectrometry method, suggesting that the developed method may be applied in the determination of Hg(II) in the water samples.
Synthesis of Activated Carbon/Chitosan/Alginate Beads Powder as an Adsorbent for Methylene Blue and Methyl Violet 2B Dyes Margaretha Aditya Kurnia Purnaningtyas; Sri Sudiono; Dwi Siswanta
Indonesian Journal of Chemistry Vol 20, No 5 (2020)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (370.415 KB) | DOI: 10.22146/ijc.49026

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The activated carbon-chitosan-alginate (KKA) beads powder was synthesized to form an adsorbent for the cationic dyes, methylene blue (MB) and methyl violet 2B (MV 2B). The aims of this research were to determine the optimum composition of KKA beads powder for the adsorption of cationic dyes and to investigate the effect of pH, adsorbent mass, contact time, and initial concentration of MB and MV 2B dyes. A desorption study was also implemented to predict the adsorption mechanisms of MB and MV 2B dyes. The KKA beads powder was prepared by mixing chitosan, Na-alginate with various variation of masses (0.6; 0.8; 1.0; and 1.2 g) and activated carbon. The KKA beads were immersed in a CaCl2 solution. The KKA beads powder was characterized using FTIR spectroscopy and SEM. The desorption study was conducted in NaCl (0.1 M and 1.0 M), ethanol (40% and 60%), and pH 4 solution. The result showed that the KKA beads powder had been successfully created, with maximum adsorption capacities of 1.34 mmol g–1 for MB and 1.23 mmol g–1 for MV 2B. The kinetics and isotherms of MB and MV dyes adsorption on the KKA beads powder followed pseudo second order kinetics model and Freundlich isotherm. The desorption study showed that 60% ethanol was the most effective desorption solution for cationic dyes.
Adsorption of Silicate Anions from Geothermal Brine Using Chitosan-Polyethylene Glycol Composite to Prevent Silica Scaling on the Dieng Geo Dipa Geothermal Energy System Nur Hayati; Hanik Humaida; Dwi Siswanta
Indonesian Journal of Chemistry Vol 21, No 5 (2021)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.49248

Abstract

Silica scaling is a common problem in geothermal power generation facilities which inhibits electricity generation. In order to provide a solution to this problem, the removal of silicate ions using CPEG-TOMAC (Chitosan-polyethylene glycol–trioctyl methyl ammonium chloride) membrane adsorbent was investigated for geothermal brine from Geo Dipa Energy, Dieng. The process is dependent on contact time, pH, and the concentration of silicate. An adsorption batch study that used adsorbents for the geothermal brine of the Dieng Geo Dipa reactor 28A showed that CPEG TOMAC at pH 6 resulted in an adsorption capacity of 72.6 mg g–1. Furthermore, the adsorption of silicate ions onto the membrane followed pseudo-second-order kinetics and the Freundlich isotherm model.
Synthesis, Characterization, and Stability Evaluation of β-Carotene Encapsulated in Starch-Chitosan/Tripolyphosphate Matrices Agnes Dyah Novitasari Lestari; Dwi Siswanta; Ronny Martien; Mudasir Mudasir
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (15.838 KB) | DOI: 10.22146/ijc.50449

Abstract

This study aims to investigate the synthesis and characterization of β-carotene encapsulated in the blending matrices of starch (native and hydrolyzed starch)-chitosan/TPP (tripolyphosphate) by examining the effects of starch-to-chitosan weight ratio, β-carotene addition level, and TPP addition level on the encapsulation efficiency (EE) and loading capacity (LC); and to evaluate their storage stability. The encapsulation was done by the dropwise addition of ethanolic β-carotene dispersion into the blending matrices. The results of XRD analysis show that the encapsulation process significantly decreases the crystallinity of the starches, chitosan, and β-carotene. Scanning electron microscope (SEM) images reveal that the encapsulation products form irregular lumps. The EE and LC tend to increase with the increase in polymer fraction of matrices and β-carotene addition level, and with the decrease in TPP addition level. The addition of chitosan and the replacement of native starch by hydrolyzed starch tend to increase storage stability of β-carotene encapsulated in the starch matrix because chitosan can act as a good film-forming and antioxidant, while hydrolyzed starch contains amylose amylopectin with a short chain which is better in film-forming ability. These results promote the use of the hydrolyzed starch-chitosan/TPP as a matrix to enhance the stability β-carotene via encapsulations.
pH Dependence on Colorimetric Detection of Hg2+ by Histidine-Functionalized Gold Nanoparticles Dewi Eviane; Dwi Siswanta; Sri Juari Santosa
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (17.202 KB) | DOI: 10.22146/ijc.51824

Abstract

In this study, we successfully developed gold nanoparticles capped with histidine (His-AuNPs) for Hg2+ detection using trisodium citrate as the reducing agent. The optimum pH for the detection of Hg2+ by His-AuNPs was 12. The addition of Hg2+ to the His-AuNPs caused the color change from red to black-blue, which is readily detectable by the naked eye. This color change is followed by a decrease in the intensity of the primary Surface Plasmon Resonance (SPR) peak at a wavelength (λ) of 525 nm and an increase in the secondary peak at λ = 650 nm. His-AuNPs effectively detected Hg2+ with limits of detection and quantitation of 1.77 µM and 5.89 µM, respectively. His-AuNPs exhibited good performance for the detection of Hg2+ in waste water collected from a steel industrial facility in Banten Province, with a recovery and a percent relative standard deviation of 115% and 1.02%, respectively.
Preparation, Characterization, and In Vitro Hemocompatibility of Glutaraldehyde-Crosslinked Chitosan/Carboxymethylcellulose as Hemodialysis Membrane Khabibi Khabibi; Dwi Siswanta; Mudasir Mudasir
Indonesian Journal of Chemistry Vol 21, No 5 (2021)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.61704

Abstract

This study aims to examine the manufacture, characterization, and in vitro hemocompatibility of glutaraldehyde-crosslinked chitosan/carboxymethyl cellulose (CS/CMC-GA) as a hemodialysis membrane. The CS/CMC-GA membrane was prepared using the phase inversion method with 1.5% CS and 0.1% CMC. The chitosan was crosslinked with glutaraldehyde in various monomers ratios, and the membranes formed were characterized by FTIR, SEM, and TGA. Furthermore, the hydrophilicity, swelling, porosity, mechanical strength, and dialysis performance of the membranes against urea and creatinine were systematically examined, and their in-vitro hemocompatibility tests were also conducted. The results showed that the CS/CMC-GA membranes have higher hydrophilicity, swelling, porosity, mechanical strength, and better dialysis performance against urea and creatinine than chitosan without modification. In addition, the hemocompatibility test indicated that the CS/CMC-GA membranes have lower values of protein adsorption, thrombocyte attachment, hemolysis ratio, and partial thromboplastin time (PTT) than that of pristine chitosan. Based on these results, the CC/CMC-GA membranes have better hemocompatibility and the potential to be used as hemodialysis membranes.