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All Journal Jurnal Ilmu Dasar EduChemia: Jurnal Kimia dan Pendidikan UNEJ e-Proceeding Jurnal Ilmiah Universitas Batanghari Jambi ALCHEMY Jurnal Penelitian Kimia Indonesian Journal of Chemistry JKPK (Jurnal Kimia dan Pendidikan Kimia)
Zulfikar Zulfikar
Department Of Chemistry, Facullty Of Mathematics And Natural Sciences, Universitas Jember
Agriculture, Biological Sciences & Forestry Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Economics, Econometrics & Finance Education Energy Environmental Science Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mathematics

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High Performance Liquid Chromatography of Amino Acids Using Potentiometric Detector With A Tungsten Oxide Electrode Yeni Maulidah Muflihah; Zulfikar Zulfikar; Siswoyo Siswoyo; Asnawati Asnawati; Qurrota Ayun
UNEJ e-Proceeding 2016: Proceeding The 1st International Basic Science Conference
Publisher : UPT Penerbitan Universitas Jember

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Abstract

High Performance Liquid Chromatography (HPLC) method combine with potentiometric detector was applied as a method for analysis of amino acids (aspartic acid, glutamic acid and arginine). The separation was carried out on a C18 column with isocratic elution of  a mixture of acetonitrile and phosphat buffer. Potentiometric detector using a tungsten oxide electrode as working electrode and Ag/AgCl as refference electrode. The detection method was based on the presence of H+ ions from amino acids. This application was a development of previous studies that was succesfully applied to detect the presence of amino acids in batch and flow systems. Amino acid determination was characterized by its retention time. Retention time of aspartic acid, glutamic acid and arginine were as follow: 8,46; 13,0; and 15,21 minutes. The optimized separation conditions obtained at a flow rate of 1,2 mL/min with 15% acetonitrile concentration, buffer pH 6,5 with phosphat concentration of 5x10-4 M. Detector performance tested by the recovery test of samples, and the results obtained for glutamic acid, aspartic acid and arginine respectively: 89,1%, 94,9%, and 110%. Linear range obtained at 10-3 M to 10-7 M.  Detection limit were 1,58x10-7 M for glutamic acid, 6,58x10-8 M for aspartic acid and 6,51x10-8 M for arginine.
Identification of Ibuprofen, Ketoprofen and Diclofenac by Using Test Strip Based on Imobilized Spesific Reagent on Nata De Coco Membrane Karisma Wulan Ningtyas; Zulfikar Zulfikar; Bambang Piluharto
Jurnal ILMU DASAR Vol 16 No 2 (2015)
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (261.862 KB) | DOI: 10.19184/jid.v16i2.1520

Abstract

Identification of ibuprofen, ketoprofen and diclofenac can be done by using simple method, it is called test strips. Test strip is made by immobilized specific reagents with entrapment technical on membrane matrix, which the used membrane nata de coco. Immobilization reagents with entrapment techniques aimed to trap reagent molecules in the space between the supporting material.The success of this imobilization can be seen from membran changing color after additional reagent and there is no leeching after additional sample on membrane. The used reagent for this identification is methyl red for ibuprofen and ketorpofen, copper acetate for ibuprofen, potassium iodide for ketorofen and mandelin for diclofenac. From the testing result can be seen that potassium iodide is the most specific reagent compare with the other threee other reagents. By using tes strip arranged with the strip made by this imobilization, test srtrip can be used to differentiate the tree other standard samples.   Keywords: entrapment, nata de coco membrane, reagent spesific, test strip.
ELECTROPOLYMERISATION AND CHARACTERISATION OF DOPED-POLYPYRROLE AS HUMIDITY SENSOR Siswoyo Siswoyo; Trio F. Nugroho; Zulfikar Zulfikar; Agus Subekti
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (354.256 KB) | DOI: 10.22146/ijc.21759

Abstract

A new type of sensing materials for humidity measurement has been developed based on conducting polymer polypyrrole synthesised from pyrrole by adding some dopant compounds, bromide and chloride, it is prepared by potentiodynamic-electropolymerisation technique. Variation of dopant types and concentration has been carried out in order to investigate the effect of this variation to the change of polymeric conductivity when interacting with water vapour. Polypyrrole-Cl (Ppy-Cl) and polypyrrole-Br (Ppy-Br) exhibit a good principal characteristic as sensor candidate namely responding proportionally to humidly variation ranging 30% - 90% relative humidity. Characterisation test for the sensor candidates has been carried out for evaluating their linearity respond toward humidity, their stability in certain period and their reproducibility in some tests. The results show that Ppy-Cl and Ppy-Br showing good linearity respond with R value in a range of 0.95 - 0.99. Their reproducibility and sensitivity were relatively good, however their respond stability were only last in few days. The stability probably is related to the stability of resulted polymeric structure that very affected by synthesis process and dopant used. It is necessary to extend the use of other dopant materials and changing the synthesis process in order to improve sensor stability. In other hand it is also necessary to characterise other performance characteristic of the sensor namely response time, and interference effect of some volatile chemicals and other gases.
The Effect of Testing Chamber on the Response Patterns of an array of Gas Sensor in Sensing Robusta Coffee Aroma from Bangsalsari and Sidomulyo, Jember Asnawati Asnawati; Siswoyo Siswoyo; Febiola Silvia Ningsih; Qurotul Ainiyah; Zulfikar Zulfikar; Tri Mulyono; Yeni Maulidah Muflihah
JKPK (Jurnal Kimia dan Pendidikan Kimia) Vol 8, No 1 (2023): JKPK (Jurnal Kimia dan Pendidikan Kimia)
Publisher : Program Studi Pendidikan Kimia FKIP Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/jkpk.v8i1.68520

Abstract

The gas sensor performance can be improved by optimizing the testing chamber design, including volume, shape, gas inlet/outlet positions, and sensor array. We studied the effect of chamber design on the gas sensor's response patterns characteristics in differentiating Robusta coffee aroma from Sidomulyo, and Bangsalsari, Jember. Hemisphere and cylindrical chambers, with three variations for each model, and a ring chamber, were used as model chambers. Eight types of gas sensors (MQ-135, MQ-136, MQ-2, MQ-3, MQ-6, MQ-7, MQ-8, and MQ-9) were used in the sensor array system to examine the gas sensor instrument performance. The resulting responses were analyzed using the reproducibility, response time, and principal component analysis (PCA) test. The result shows that the reproducibility value for all hemisphere chamber models, cylindrical chamber model-1, and ring chamber indicated an excellent sensor performance (%RSD<20%). Meanwhile, the cylindrical chambers model-2 and 3 resulted in %RSD>20%, indicating the low performance of the gas sensor. Among all variations, hemisphere chamber model-1, a hemisphere chamber with the inlet position lower than the outlet gas position, has the best performance due to the shortest response time, high-intensity signal, and performing ability to distinguish the response patterns characteristics of Robusta coffee aroma from Sidomulyo and Bangsalsari, Jember, Indonesia. In this study, we found that changing the testing chamber design, volume, and inlet/outlet position resulting different gas sensor responses to the coffee aroma. The proposed instrument can distinguish the coffee aroma from a different origin.
Batch Injection Potentiometry Asam Aspartat, Asam Glutamat dan Arginin Menggunakan Elektroda Tungsten Oksida Yeni Maulidah Muflihah; Heny Masruroh; Zulfikar Zulfikar
ALCHEMY Jurnal Penelitian Kimia Vol 10, No 1 (2014): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (259.016 KB) | DOI: 10.20961/alchemy.10.1.18.1-10

Abstract

The presence of aspartic acid, glutamic acid and arginine in solution can be detected by potentiometric method using tungsten oxide electrode in a batch system. Characterization of tungsten oxide electrode used include linear range, limit of detection, sensitivity and reproducibility. Buffer type and concentration effect also studied to optimize the measurement results. Optimum conditions for detecting arginine was at pH 6.0 with a phosphate buffer concentration of 0.5 x 10-3 M. Correlation coefficient was obtained for 0.9864, the detection limit of 5.24 x 10-6 M, sensitivity 16.1 mV/decade with reproducibility 0 –7 %. Glutamic acid has a correlation coefficient of 0.9789, the detection limit of 3.80 x 10-6 M, the sensitivity of 9.2 mV/decade and reproducibility of 0 – 6 %. Aspartic acid has a correlation coefficient of 0.9949, the detection limit of 7.76 x 10-6 M, sensitivity of 13.4 mV/decade and reproducibility of 0 – 5 %.
Optimasi dan Karakterisasi Kinerja Sistem Pengukuran Potensiometrik Fosfat dengan Elektroda Kobalt Secara Flow Injection Analysis Putri F. Rianasari; Zulfikar Zulfikar; Siswoyo Siswoyo
Jurnal Ilmiah Universitas Batanghari Jambi Vol 23, No 2 (2023): Juli
Publisher : Universitas Batanghari Jambi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33087/jiubj.v23i2.3714

Abstract

Phosphorus is known as an essential nutrient required by plant in large numbers and absorbed in the form of phosphate ions, either as a primary orthophosphate ion H2PO4- or secondary orthophosphate ion HPO42-. Concentration of the phosphorus in the soil is usually determined by the spectrophotometric method, while the potentiometric method has not been widely used because of the availability of the phosphate-selective electrodes are not yet available in the market. This research has been conducted in the development and assessment of performance of the potentiometric method that utilizes cobalt metal in the quantitative determination of the phosphate ions in the flow system. Firstly it was performed optimization of pH and concentration of the used buffer solution and the flow rate of the solution to obtain the optimum response of the cobalt electrode in the presence of phosphate ions. It was then followed by an evaluation of the working performance of the flow injection potentiometry method and an interference test of some solutions that are commonly used as a solvent extractors of soil samples. The result showed that the optimum system was achieved when the buffer solution was set to pH 4 at concentration of 1 x 10-3 M and at the flow rate of 2 mL/minute. According to the characterisation results of the method in the process of phosphate determination, the method has a linearity of 0.99, detection limit of 4.86 x 10-5 M, sensitivity of 22.569 mV / decade and precision of ≤ 5%.
Development of Polypyrrole/Graphene Oxide Gas Sensor for Detection of Coffee Aroma Muflihah, Yeni Maulidah; Ardyanti, Zona Salsabila; Zein, Inayatul Aulia Rizka; Zulfikar, Zulfikar; Siswoyo, Siswoyo; Asnawati, Asnawati; Mulyono, Tri
EduChemia: Jurnal Kimia dan Pendidikan Vol 8, No 1 (2023)
Publisher : Department of Chemical Education Faculty of Teacher Training and Education Universitas Su

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30870/educhemia.v8i1.18231

Abstract

Detecting and characterizing coffee aroma is crucial for determining the quality of coffee. While gas chromatography is the standard method, using gas sensors is a feasible alternative. The electrode material used extensively influences the response produced by the gas sensor. This study explores using composites of the conductive polymer polypyrrole (PPy) and graphene oxide (GO) as materials for gas sensor electrodes. In the study, we synthesized PPy and GO and characterized them using UV-Vis and FTIR spectrophotometry, confirming that the compounds obtained were PPy and GO. The researchers varied the composition and thickness of PPy/GO in electrode fabrication. Varying the percentage of GO in the composite by 0, 5, 10, and 15% GO resulted in different PPy/GO compositions, while electrode thicknesses observed were 0.083, 0.21, 0.39, and 60 mm. Electrode characterization, including sensitivity, conductivity, and response time, showed that the PPy/GO electrode with a composition of 15% GO and a thickness of 0.21 mm had the best response. The PPy/GO sensor was tested on the aroma of Robusta coffee from three different plantations in the Jember area, East Java. It was able to distinguish the aroma of coffee. Measurement of electrode reproducibility in measuring each sample for one month showed consistent results from week to week, with a %RSD of less than 5%. The research results demonstrate that the PPy/GO sensor with a GO composition of 15% and a thickness of 0.21 mm has excellent potential for differentiating the aroma of coffee with different compositions of constituent compounds.
Co-Authors Agus Subekti Ardyanti, Zona Salsabila Asnawati Asnawati Bambang Piluharto Febiola Silvia Ningsih Heny Masruroh Karisma Wulan Ningtyas Mulyono, Tri Nida Andriana Putri F. Rianasari Qurotul Ainiyah Qurrota Ayun Siswoyo Siswoyo Tri Mulyono Trio F. Nugroho Yeni Maulidah Muflihah Yudi Aris Sulistiyo, Yudi Aris Zein, Inayatul Aulia Rizka