Chemistry

Selective melamine sensors based on nanoporous carb on paste /molecularly imprinted polymer have been s The study begins with the synthesis of MIP monomer mixture of methacrylic acid (MAA), and ethylene gly col dimethacrylate (EGDMA) cross linker, benzoyl peroxi de initiator, and melamine template. Membrane elect rodes are fabricated by mixing nanoporous carbon and MIP with a certain ratio of inserted into the electrode sur face. The optimization of sample measurements which includes melamine test of pH value of a solution pH and memb rane composition. Further characterization of the electr odes was done by determining the Nernst factor, mea surement range, selectivity, and lifetime. Validation method was done by determining the accuracy, precision, a nd the detection limit. Based on the data from FTIR, has b een successfully synthesized MIP with BET analysis showing that MIP has a larger surface area , a larger pore volum e, and a larger pore diameter than the MIP before extraction...

Nanotechnology research in the realm of forest products can be exploited from lignocellulose into nano carbon. The research was aimed to provide the potency of nano carbon structure from lignosellulose as bioenergy or biosensor material. O The materials of teak wood and bamboo were carbonized into charcoal at 400-500 C followed by activation using O chemical and physical processes at 800 C for 60 minutes. This process produced charcoal with high crystalinity and surface area. After purification and activation, the activated charcoal was subsequently doped process with Zn and Ni metals which O then followed by sintering using spark plasma at 1300 C. The qualities and structure of all the resulting carbon were evaluated using nano scale devices i.e. Pyrolysis Gas Chromatography Mass Spectrometer, Scanning Electron Microscope-Energy Diffraction X-ray Spectrometer, X-ray Diffractometer, I-V meter and potensiometer. Results showed that the best activated charcoal produced from the chemical-physical activation (KOH steam) possessed high fixed carbon of 84.29%; 2 surface area of 850.5 m /g, crystallinity of 38,99% and resistancy of 0.10. The teak activated charcoal which intercalated by Ni at ratio of 1:5 produced the best properties with crystallinity degree of 73.45% and conductivity of 433.86 S/m. The sintered teak activated charcoal had crystallinity degree of 78.29% with I-V meter pattern in sigmoid shape and the potentiometer response formed a slope approaching the Nerst factors. Nano carbon produced from lignocellulose is a semiconductor and more suitably use for biosensors, particularly the one derived from teak wood.

In the forest products field, the nano technology that can be developed is among others nano carbon derived from lignocel ulosic stuffs. In relevant, this information and technology on the charcoal processing from l paper observes lignocellulosic stuffs into nano carbon. The lignocellulosic stuffs used in this research consisted of teak wood, further carbonized into charcoal at 400-500 C using drum kiln and then purified by re-carbonizing it at 800 C for 60 minutes

Development of the uric acid sensor through coating of glassy carbon (GC) electrode with imprinting zeolite (IZ) was carried out. Zeolite was synthesized by mixing TEOS, TBOT, TPAOH, and water followed by hydrothermal process. Zeolite was molded together with uric acid to produce IZ. The deposition potential of IZ and uric acid to the GC surface was -0.6 V during 150 sec with addition of KNO3 0.02 M as supporting electrolyte. The method gives linearity of 0.9834 (concentration 5.6x10-9M - 2.8x10-8 M), precision 1.89 - 7.65%, sensitivity 0.33 µA/nM/cm2, limit of detection 5.9x10-9 M, and accuracy 96.26 ± 0.55% (n = 5). The developed sensor showed a high selectivity toward uric acid. The presence of ascorbic acid, creatine, and creatinine with an equal concentration with uric acid did not interfere on the uric acid analysis.

A research on the analysis of copper metal in the cooking oil saponification by AAS method. This study aimed to validate analytical methods, including precision and accuracy in the determination of copper metal in cooking oils through saponification and knowing destructed Cu content in cooking oils on the market. This research was done by creating a simulation of cooking oils and then added with a solution with various concentrations of Cu2+, reacted with KOH for saponification, then destructed dried, and absorbance was measured using an atomic absorption spectrometer. Results of accuracy (recovery) be obtained average of 96.88, 97.35, and 97.36% and precision values of 0.8233, 0.3154, and 0.4803%. It can be concluded that this method is very well used to determine the concentration of copper metal contained in cooking oils, and Cu content in cooking oils on the market for bulk cooking oil 1 at 11.5 mg/kg, bulk cooking oil 2 at 10.9 mg/kg, and for branded cooking oil at 7.4 mg/kg.

The release of drugs from solid drug delivery materials has been studied intently in recent years. Quantitative analyses achieved from in vitro dissolution becomes easier if a zero-order mathematical model is used. Non-gelatin nutraceutical hard-shell capsules of zero size (approximately 0.7-0.8 cm) were produced from carrageenan-based natural polymers, namely carrageenan-alginate (CA) and carrageenan-starch (CS). Disintegration, dissolution and zero-order drug release kinetics of hard-shell capsules containing 100 mg of salicylamide were studied. The disintegration time of CA and CS were observed to be less than 30 min for both CA and CS. In vitro dissolution profile showed that the percentage dissolution of CA capsules was better at pH 4.5, while that of CS was poor at pH 1.2, 4.5 and 6.8. Determination of drug release kinetics profiles of carrageenan-based hardshell capsules utilized the Noyes-Whitney and Peppas-Sahlin modification rules for zero-order. The drug release from carr...

Perkembangan ilmu pengetahuan abad ini dan yang akan datang sudah memasuki teknologi nano. Di bidang hasil hutan, teknologi nano yang dapat dikembangkan di antaranya adalah nano karbon dari bahan berlignoselulosa. Tujuan penelitian ini adalah menyediakan informasi dan teknologi pengolahan arang sebagai bahan baku nano karbon dari bahan lignoselulosa. Bahan baku lignoselulosa yang digunakan dalam penelitian ini adalah kayu jati, dan bambu yang dikarbonisasi pada suhu 400-500 ° C menggunakan kiln drum, arang yang dihasilkan dimurnikan dengan jalan dipanaskan pada suhu 800 ° C selama 60 menit yang sebelumnya didoping dengan logam Zn, Ni dan Cu. selanjutnya dihaluskan menggunakan high energy mechanic (HEM) selama 48 jam. Arang dengan kristalinitas tinggi disintering menggunakan spark plasma pada suhu 1.300 ° C. Karbon yang dihasilkan diuji sktuktur dan sifatnya menggunakan Py-GCMS, SEM-EDX, XRD,dan sifat elektrik. Hasil penelitian menunjukkan struktur karbon yang terbaik dihasilkan dari...

Nahptol AS-BO is one of the synthetic dyes often used in the dyeing process of batik fabric. The treatment of the wastewater released is a serious problem from an environmental point of view. The present investigation is focused at constant potential electrochemical degradation of naphthol AS-BO using a nanoporous carbon paste electrode in a solution containing NaCl as a supporting electrolyte. The effect of the potential applied, the solution pH and the degradation time is followed. It is found that the optimum values of the potential and pH refer to 12 V and 1, correspondingly. It is experimentally verified that the degradation process is of ECE mechanism, while the rate-determining chemical step is of a second order. The method studied provides COD value decrease to 90.84 %, while naphthol AS-BO presence decreases to 88.74 %.

Ultra trace determination of lanthanum (Ⅲ) has been studied by adsorptive stripping voltammetry methods using an alizarin S as complexing agent and carbon paste electrode as working electrode. The electrode was made from mixed of carbon powder and paraffin in micropipette tip with diameter of 4 mm. This method consists of two steps. The first step is the formation and adsorptive accumulation of metal ion with chelator at the electrode surface. The second step is stripping the complex from the electrode surface into the solution. The stripping step generates current which is recorded as voltammogram. The optimum conditions of instrumental parameter obtained were accumulation potential of 600 mV, accumulation time of 120 seconds, and pH of solution of 5.5. In this research, the limit detection obtained was 2.3348×10^(-12) M (3.24×10^(-11) μg/L) with sensitivity of 16.52 (nA/10^(-11) M) and the precision of standard solution of La(superscript 3+) with concentration of 2×10^(-12) M, 4×1...

Potentiometric sensor of melamine based on nanoporo us carbon/molecularly imprinted polymer (MIP) have been made and characterized. The purpose of research ar e to know the optimum conditions in the analysis of melamine and validation method. Molecularly Imprinted Polymer (M IP) is synthesized by mixing 0,2 mmol of melamine as a template, 0,8 mmol of methacrylic acid as monomer, 2,4 mmol of ethylen glycol dimethacrylate as crossl inker end 1 mmol benzoyl peroxide as initiator. Electrode is ma de by mixing nanoporous carbon, MIP and paraffin in the ratio of 45:20:35. From this research it is obtained opti mum pH of melamine solution is 3,0-4,0, the Nernst factor is 54 mV/decade and range of measurement is 10 -6 M‐10 -2 M. The limit of detection that can be measured by n anoporous carbon/MIP is 8,86x10 -7 M.. The selectivity coefficient of electrode for Na + , K + , Ca 2+ end Mg 2+ ions are 2,904x10 -6 , 6,072x10 -8 , 2,632x10 -9 , and 2,566x10 -9 which means that the ion do not inter...

A new modified electrode is constructed based on uric acid shape selectivity of TS-1 zeolite modified glassy carbon electrode. Fourier Transform Infrared, X-ray Diffraction, and stripping voltammetry were used to characterize material. The imprinting TS-1 zeolite modified glassy carbon electrode exposes Gaussian Graphic and also responses high selectivity, reproducibility and current for determination of uric acid.

Natural bentonit from Pacitan was evaluated as a support matrix for amylase immobilization, in developing industrial technology for starch hydrolyzing. Bentonit is a clay which has high adsorption capacity. Amylase was product from Endomycopsis fibuligera. This amylase has optimum activity at pH 5.5 It was hoped that at this optimum pH, amylase molecules have a negative netto charge and adsorped easily by the nature bentonite. The aims of this research are to investigate whether the nature bentonit can adsorps amylase by simple ion exchange process; to determine the characteristic and optimum conditions of amylase adsorption into bentonite. The bentonitesample waspowdered and investigated characters, included optimum conditions and characteristic of amylase extract adsorption, by method of simple shaking at room temperature. Amylase immobilization prosess was done in the same manner. The bentonit adsorped amulase well at optimum conditions of pH5 during, where 888 mgram protein in a...

Lead concentration greater than 10 µg/L make health problem among other thing decrease in intelligence, nervous system disorders, so lead rapid analysis with high accuracy and precision is needed. The aim of this research are to know the composition of ESI-Pb 2+ membrane silver wire coated type PVC/1,10dibenzyl-1,10-diaza-18-crown-6, optimum pH condition and to study the characteristic electrode, such as Factor Nernst, range measurement, limit detection, accuracy and precision, selectivity, and blood serum sample accuracy. The result has shown that potensial measurement with Ag/AgCl reference electrode give the best membrane composition of 45 mg PVC, 90 mg NPOE, 10 mg KTCPB, 5 mg 1,10-dibenzyl-1,10diaza-18-crown-6 in 0,5 ml THF solution. The optimum pH is 3-7 and gave 29,64 mV as Factor Nernst with range measurement 10-1-10-6 M, limit detection was noted at 1,28.10-6 M, and accuracy is 73%-157% in 10-6-10-1 M Pb 2+ solution with variation coefficient 0,70-1,2. The selectivity constanta is , < 1 toward K + , Ca 2+ , Mg 2+ , Na + , Cu 2+ dan Fe 3+ as interfering ions. Recovery percentage of Ion Selective Electrode Pb 2+ silver wire coated type with PVC /1,10-dibenzyl-1,10-diaza-18-crown-6 to blood serum sample has shown 95%-143% and 110%-117% compare with AAS.

Uric acid (UA), a vital biological substance, should be accurately detected in clinical monitoring and diagnosis. An electrochemical sensor was developed for UA determination based on polymelamine/gold nanoparticle-modified carbon paste electrode (AuNPs/PM/CPE). Carbon paste electrode (CPE) was made by mixing carbon and paraffin powder at a ratio of 7:3. PM/CPE was made using 1 mM melamine electropolymerisation in 0.1 M NaOH solution on the CPE surface with the cyclic voltammetry (CV) technique with a potential range of 0 to +1.6 V, and a scan rate of 100 mV/s. AuNPs/PM/CPE electrodes were made using Au electrodeposition on the PM/CPE surface using a 1 mM HAuCl4 solution containing 0.1 M Na2SO4. Electrodeposition was performed by CV in the potential range of -0.6 to +1.5 V, with a scan rate of 50 mV/s. The electrocatalytic activity towards UA was systematically studied by CV techniques on the surface of CPE, PM/CPE, AuNPs/CPE, and AuNPs/PM/CPE in phosphatebuffered solution (PBS) at ...

Modifications of carbon paste electrodes (CPE) with polymelamine (PM) and gold nanoparticles (AuNPs) as dopamine (DA) sensors have been investigated. Electrodes were made by coating PM by electropolymerization from melamine solution on the surface of CPE, then AuNPs were made by electrochemically reducing HAuCl 4 solution. AuNPs/PM/CPE electrodes were used as dopamine sensors by using cyclic voltammetry (CV) and pulse differential voltammetry (DPV) techniques. The results showed that the electrodes gave a linearity of 0.2-11 μM, a detection limit of 0.067 μM, and recovery value of 98.78 % ± 0.34% in the analysis of urine samples spiked with dopamine. The electrodes gave perfect peak potential for separation from DA, uric acid (UA) and ascorbic acid (AA).

Polymelamine/gold nanoparticle modified carbon paste electrode (PM/AuNPs/CPE) has been developed for voltammetric study of ascorbic acid (AA). The PM/CPE was prepared onto carbon paste electrode surface via electropolymerization, then it has been deposited gold nanoparticle (AuNPs) via electrodeposition for PM/AuNPs/CPE. In pH 7.0 phosphate buffer, PM/AuNPs/CPE was oxidized during the cyclic potential sweep between 0.0 V and 1.5 V, forming polymer and gold nanoparticle at the carbon paste electrode (CPE) surface. The electrochemical behavior of ascorbic acid at the bare CPE, PM/CPE, AuNPs/CPE and PM/AuNPs/CPE were investigated. The oxidation peak potential of ascorbic acid shifts to more negative potential at PM/AuNPs/CPE Moreover, the oxidation peak current significantly increases at PM/AuNPs/CPE. The PM/AuNPs/CPE electrode exhibits a quasi-reversible electron with a peak separation 130 mV. These fenomena indicate that PM/AuNPs/CPE shows highlyefficient catalytic activity to the oxidation of ascorbic acid.

The high level of uric acid in the body is often associated with some diseases such as hyperuricemia, hypertension, renal and cardiovascular disease. Therefore early detection of the levels of uric acid is required. Spectrophotometry is the method commonly used in the medical field to determine the uric acid level. Its detection limit refers to a low uric acid level in a serum sample as the complexity of the serum matrices decreases its selectivity. The development of an imprinted zeolite based sensor to analyze uric acid by potentiometry is conducted. The carbon paste-IZ electrode shows a range of measurement of 10-6 M 10-4 M, a Nernst factor of 28.2 mV decade-1, and response time of 34 s 44 s. The developed electrode has a high selectivity towards uric acid. Ascorbic acid, creatine, or creatinine do not interfere with uric acid analysis using the electrode suggested as the value of the selectivity coefficient (Kij) is less than 1. The method recovery equals (113.18±14.79) % (n = 3...

Nanotechnology research in the realm of forest products can be exploited from lignocellulose into nano carbon. The research was aimed to provide the potency of nano carbon structure from lignosellulose as bioenergy or biosensor material. O The materials of teak wood and bamboo were carbonized into charcoal at 400-500 C followed by activation using O chemical and physical processes at 800 C for 60 minutes. This process produced charcoal with high crystalinity and surface area. After purification and activation, the activated charcoal was subsequently doped process with Zn and Ni metals which O then followed by sintering using spark plasma at 1300 C. The qualities and structure of all the resulting carbon were evaluated using nano scale devices i.e. Pyrolysis Gas Chromatography Mass Spectrometer, Scanning Electron MicroscopeEnergy Diffraction X-ray Spectrometer, X-ray Diffractometer, I-V meter and potensiometer. Results showed that the best activated charcoal produced from the chemica...

Hydroquinone is the most effective whitening agent in skin whitening cosmetics. It has the ability to whiten the skin in a relatively shorter time compared to other whitening agents. However, based on the regulations of the Indonesian Food and Drug Administration (BPOM) and the United States Food and Drug Administration (FDA), the use of hydroquinone in whitening cosmetics is prohibited and is given zero tolerance. Therefore, it is the aim of this study to develop an alternative method to analyze the presence of hydroquinone in cosmetics that is easier, inexpensive, selective, and accurate. The result showed that the best composition of the electrode membrane which gave the best outcome was carbon: paraffin: ferrocene with each ratio of 6 : 3: 1. The validity of the hydroquinone analysis method that uses carbon/ferrocene paste as the electrode shows good results with the working range of 0.20-10 µM, the sensitivity of 10.436 µA/µM, and detection limit of 0.06 µM. It is also selective in the analysis of a mixture of hydroquinone and arbutin. These electrodes have excellent accuracy in recovering hydroquinone analysis in cosmetic samples with an average recovery value of 99%. This electrode can also be used for arbutin analysis in cosmetics with an accuracy of 99%. This method is suitable to be used in skin whitening analysis, both hydroquinone and arbutin.