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DAYA SERAP KULIT KACANG TANAH TERAKTIVASI ASAM BASA DALAM MENYERAP ION FOSFAT SECARA BATH DENGAN METODE BATH Irdhawati Irdhawati; Alling Andini; Made Arsa
Jurnal Kimia Riset Vol. 1 No. 1 (2016): Juni
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (624.087 KB) | DOI: 10.20473/jkr.v1i1.2443

Abstract

AbstrakKulit kacang tanah digunakan sebagai adsorben untuk menyerap ion fosfat dalam larutan. Sebelum digunakan sebagai adsorben, kulit kacang tanah dicuci, dikeringkan, dihaluskan menggunakan blender dan diayak dengan ukuran partikel ≤ 100 mesh. Serbuk halus diaktifkan dengan asam (H2SO4) dan basa (NaOH) pada berbagai konsentrasi. Selanjutnya, adsorben dengan dan tanpa aktivasi digunakan untuk menentukan kadar fosfat yang terserap secara optimum. Parameter adsorpsi yang digunakan adalah waktu kontak dan kapasitas adsorpsi. Kapasitas adsorpsi diukur dengan mereaksikan ion fosfat dengan adsorben, dan sisa analit dalam larutan ditambahkan dengan amonium molibdat membentuk senyawa kompleks amonium fosfomolibdat berwarna biru dalam larutan asam. Konsentrasi senyawa kompleks ditentukan dengan metode spektrofotometri UV-Visible.Hasil dalam proses aktivasi menunjukkan konsentrasi optimum asam adalah 0,05 M, dan basa sebesar 0,5 M. Waktu kontak optimum diperoleh 45 menit untuk adsorben tanpa aktivasi dan aktivasi basa,  sedangkan untuk aktivasi asam 30 menit. Kapasitas adsorpsi optimum berturut-turut adalah  8,5 mg/g; 8,8 mg/g, dan 10,4 mg/g menggunakan adsorben tanpa aktivasi, teraktivasi asam dan teraktivasi basa. Adsorben teraktivasi basa memiliki kapasitas adsorpsi tertinggi dibandingkan adsorben tanpa aktivasi dan teraktivasi asam. Kata kunci: kulit kacang tanah, ion fosfat, adsorpsi, amonium fosfomolibdat  AbstractPeanut shell was used as adsorbent to adsorb phosphate ion in solution. Before using as adsorbent, the peanut shell was washed, dried, mashed and sifted with particle size <100 mesh. The fine powder was activated by acid (H2SO4) and base (NaOH) with various concentrations. Furthermore, the adsorbent with and without activation was used to determine the optimum phosphate concentration that can be adsorbed. The parameters adsorption such as contact time and adsorption capacity, were examined. The adsorption capacity was measured by reacting the phosphate ion with adsorbent, and the rest of analyte in the solution reacted with ammonium molybdate formed ammonium phospho molybdate complex compound whose blue color in acidic solution. The concentration of complex compound can be determined by UV-Visible spectrophotometry method. The results in activation process showed the optimum concentration of acid is 0.05 M, and base is 0.5 M. The optimum contact time obtained 45 minutes for adsorbent without and base activated, while 30 minutes for acid activated. The optimum adsorption capacity is 8.5 mg/g, 8.8 mg/g, and 10.4 mg/g using adsorbent without, acid, and base activated, respectively. Adsorbent in base activated has the highest adsorption capacity compared with no and acid activated. Keywords: peanut shell, phosphate ion, adsorption, ammonium phospho molybdate
TEKNIK VOLTAMETRI PELUCUTAN ANODIK GELOMBANG PERSEGI UNTUK PENENTUAN KADAR LOGAM Cu DALAM KANGKUNG AIR Irdhawati Irdhawati; Liana Sari; Ida Ayu Raka Astiti Asih
Jurnal Kimia Riset Vol. 1 No. 2 (2016): Desember
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (418.317 KB) | DOI: 10.20473/jkr.v1i2.3094

Abstract

ABSTRAK Analisis logam berat Cu(II) dilakukan dengan metode voltametri pelucutan anodik gelombang persegi. Penelitian ini bertujuan untuk mengetahui validitas metode voltametri pelucutan anodik yang digunakan dalam pengukuran kadar logam Cu(II) dalam sampel kangkung air di muara sungai Badung. Elektroda glassy carbon digunakan sebagai elektroda kerja, Ag/AgCl sebagai elektroda pembanding, dan kawat platina sebagai elektroda pembantu. Parameter yang dioptimasi meliputi waktu deposisi dan laju pindai dalam larutan standar Cu(II) 500 ppb. Validasi metode ditentukan dengan menentukan rentang konsentrasi linier, limit deteksi, keberulangan pengukuran, dan persen perolehan kembali. Teknik voltametri pelucutan anodik kemudian digunakan untuk mengukur kadar logam Cu(II) pada sampel kangkung air.Hasil optimasi pengukuran kadar logam Cu(II) yaitu waktu deposisi optimum 60 detik dan laju pindai optimum 10 mV/detik. Pengukuran validitas larutan standar logam Cu(II), rentang konsentrasi linier larutan 50 ~500 ppb dan memiliki nilai koefisien korelasi 0,9983. Limit deteksi 35 ppb, keberulangan pengukuran memiliki rasio Horwitz kurang dari 2, dan persen perolehan kembali 99,35% ± 0,4526. Hasil pengukuran sampel tanaman kangkung memiliki kandungan logam Cu(II) sebesar 4,0 ppm. Berdasarkan Keputusan Direktur Jenderal Pengawasan Obat dan Makanan batas maksimum cemaran logam dalam makanan untuk logam Cu(II) adalah 5,0 ppm. Oleh karena itu dapat diketahui bahwa kandungan logam Cu(II) tidak melebihi kadar maksimum yang diperkenankan. Kata Kunci : logam berat, voltametri pelucutan anodik gelombang persegi, kangkung airABSTRACTHeavy metal analysis of Cu(II) was measured by square wave anodic stripping voltammetry method. The aim of this research is to know the validity of square wave anodic stripping voltammetry method for determination of Cu(II) in water spinach from the estuary of  Badung river. Glassy carbon, Ag/AgCl, and Pt wire electrodes were used as working electrode, reference electrode and counter electrode, respectively. Optimized parameter involved the deposition time and scan rate in standard solution Cu(II) 500 ppb. Furthermore, the validation method was examined by determination of linear concentration range, limit of detection, repetition of measurement, and percent of recovery. Moreover, the result of validation was used for observing of heavy metal Cu(II) content in water spinach.             The result of optimum deposition time is 60 s. Meanwhile, the scan rate optimum is 10 mV/s. Measurement for standard solution 50 ~ 500 ppb on linear concentration range, with correlation coefficient 0,9983. Limit of detection is 35 ppb, repetition of measurement for metal has Horwitz ratio less than 2, and percent recovery of Cu(II) measurement is 99,35% ± 0,4526. The measurement of Cu(II) content in the water spinach sample contain Cu(II) 4,0 ppm. Based on Decree of Directorate General for Drug and Food Control, the treshold line for Cu(II) contamination for food is 5,0 ppm. Therefore, the water spinach sample contain Cu(II) is less than accepted value. Keyword : Heavy metal, square wave anodic stripping voltammetry, water spinach
Teknik Voltammetri Pelucutan Anodik Menggunakan Elektroda Glassi Karbon dalam Penentuan Kadar Logam Fe dalam Terong Ungu Irdhawati Irdhawati; Vivi Eka Indrayani; Emmy Sahara
Jurnal Kimia Riset Vol. 4 No. 2 (2019): Desember
Publisher : Universitas Airlangga

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20473/jkr.v4i2.15897

Abstract

Terong ungu adalah salah satu jenis tanaman yang banyak dibudidayakan. Tingginya permintaan terong menyebabkan petani menggunakan pupuk dan pestisida dari bahan kimia untuk meningkatkan produksi. Penggunaan bahan kimia yang berlebihan dapat mencemari lingkungan. Dalam penelitian ini kadar logam Fe dalam terong ungu ditentukan dengan teknik voltammetry pelucutan anodic. Elektroda kerja yang digunakan adalah glassi karbon, Ag/AgCl sebagai elektroda pembanding, dan kawat platina sebagai elektroda lawan. Parameter pengukuran yang dioptimasi meliputi waktu deposisi, potensial deposisi, dan laju pindai. Selanjutnya dilakukan validasi rentang konsentrasi linier, limit deteksi, limit kuantisasi, keberulangan, dan perolehan kembali. Hasil yang diperoleh yaitu waktu deposisi optimum selama 40 detik, potensial deposisi optimum pada -0,27 V, serta laju pindai 2,5 mV/s. Linieritas larutan standar Fe berada pada rentang 5 sampai 100 mg/L, dengan koefisien korelasi 0,9964. Limit deteksi dan limit kuantisasi berturut-turut 18,36 mg/L dan 37,79 mg/L. Keberulangan pengukuran menghasilkan nilai rasio Horwitz yang lebih kecil dari dua. Perolehan kembali standar logam Fe yang ditambahkan ke dalam larutan sampel diperoleh 100,00 ± 0,07%. Kadar Fe dalam terong ungu pada kondisi pengukuran optimum diperoleh 80,40 ± 1,85 mg/kg. Nilai tersebut lebih kecil dari Standar Nasional Indonesia (SNI) untuk kadar logam dalam bahan pangan yaitu 5000 mg/kg.
Modification of Carbon Paste Electrode with Crown Ether (Dibenzo-18-Crown-6) for Ascorbic Acid Analysis Using Differential Pulse Voltammetry Method Irdhawati Irdhawati; Manuntun Manurung; Anisha Maulinasari
ALCHEMY Jurnal Penelitian Kimia Vol 11, No 2 (2015): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.11.2.728.175-191

Abstract

In this research, the modified carbon paste electrode with crown ether (dibenzo-18-crown-6) has been prepared, for determination of ascorbic acid. Some of parameters observed were optimization of crown ether composition in carbon paste, pH of solution, linear concentration range, limit of detection, reproducibility, and recovery. The optimum performance of the prepared electrode was applied for determination of commercialsampleswhich contain of ascorbic acid. The result of this research showsthat the optimum composition of crown ether in carbon paste is 0.6 % at pH 4. Linear range of concentration obtained is from 2 - 200 μM. The detection limit and percentage of recovery are 1.243 μM and 101.31 %, respectively. The modified electrode has HorRat value less than 2, it indicates a good reproducibility. Analysis of 4 commercial samples which contain of ascorbic acid were in agreement with the content listed in the label with the suitability of 94 - 100 %.
Comparison of Wet and Dry Digestions in the Analysis of Fe in Spinach by Atomic Absorption Spectrophotometry Irdhawati Irdhawati; I Gusti Ayu Putu Yunita Riyastini; Manuntun Manurung
The Journal of Pure and Applied Chemistry Research Vol 11, No 1 (2022): Edition January-April 2022
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2022.011.01.607

Abstract

The method of digestion as a part of sample preparation is very important to determine the accuracy of the analysis result. In this study, the methods of wet and dry digestions were applied to determine of Fe content in several kinds of spinach obtained from the traditional market in Denpasar Bali. This research aimed to compare the result of Fe analysis by AAS method using both of digestion methods. This research was divided into several steps starting from sampling, determination of the samples species, sample preparation, digestion by wet digestion using aqua regia and dry digestion in the furnace, and Fe analysis by AAS. The result showed that the concentrations of Fe in root spinach, red spinach, cut spinach, and tricolor spinach through wet digestion method varied between 68.08–105.45 mg/kg, while the concentrations of Fe by dry digestion obtained between 27.52–42.03 mg/kg, which was over the accepted value. Based on the one-way ANOVA statistical test with a significance level of 5%, there was a significant differences of Fe concentration in spinaches by wet and dry digestions.
Carbon Paste Electrode Modified by Dibenzo-18-crown-6 for the Determination of Paracetamol Using Differential Pulse Voltammetry Technique Irdhawati Irdhawati; Ni Ketut Shinta Mas Methaninditya; Anak Agung Bawa Putra
Indonesian Journal of Chemistry Vol 23, No 1 (2023)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.74393

Abstract

The fabrication, optimization and validation of measurement using a modified carbon paste electrode (CPE) with dibenzo-18-crown-6 were carried out for the determination of paracetamol in commercial products. The pH, dibenzo-18-crown-6 concentration in carbon paste, and scan rate parameters were optimized. Validation of the measurement was observed from linear concentration range, LoD, LoQ, precision, and percentage of the recovery. The result showed that the optimum pH was at 2, the optimum concentration of dibenzo-18-crown-6 in carbon paste was 0.6%, optimum scan rates were 35 mV/s for CPE, and increased to 50 mV/s using modified CPE. The linear concentration range for CPE was obtained at 10-300 µM with LoD and LoQ of 28.88 and 96.28 µM, respectively. Meanwhile, CPE modified with dibenzo-18-crown-6 gave wider linear concentration range at 1–700 µM with LoD and LoQ of 52.36 and 174.53 µM, respectively. The CPE and modified CPE had good precision, with Horwitz ratio values of less than two. The percentage of recovery for two samples with three replicates measurements was obtained (89.81 ± 1.38)% and (108.02 ± 0.42)% for samples A and B, respectively. Dibenzo-18-crown-6 modified CPE was used for the determination of paracetamol in both samples yielding 97–98% compared with the paracetamol composition on its labels.
Activated Bentonite Modified-Carbon Paste Electrode for Determination The Level of Copper Ion (Cu2+) in Tomato Irdhawati Irdhawati; Ekki Inur Ingtyas Mawarni; Ayu Jyostosya Yotirani Arya Wijana; Feby Silvia Sitio; Ni Putu Gita Widi Saraswati; Emmy Sahara
Aceh International Journal of Science and Technology Vol 9, No 3 (2020): December 2020
Publisher : Graduate Program of Syiah Kuala University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (540.077 KB) | DOI: 10.13170/aijst.9.3.17856

Abstract

Voltammetry is an electroanalytical method measure current as a function of applied potential. The working electrode in the voltammetry method dramatically affects the result of the electrochemical analysis. Modification of the working electrode can improve measurement performance. In this research, the carbon paste electrode (CPE) was modified with Bentonite (CPEB) to determine copper's level using differential pulse voltammetry technique. CPE and CPEB were used as working electrodes, handmade Ag/AgCl as a reference electrode, and Pt wire as the counter electrode. The measurement parameters were optimized, including the composition of bentonite in carbon paste and scan rates. Furthermore, the measurement conditions were validated, involved linear concentration range, detection limit (LoD), the limit of quantization (LoQ), repeatability, and recovery. The results showed that bentonite's optimum composition was 40% of the total weight of graphite and activated bentonite.  The scan rate optimum for Cu2+ measurement was obtained at 20 mV/s with CPE and became faster to be 25 mV/s with CPEB. The linearity of the standard solution measurement of Cu2+ using CPE was in the range of 5 to 100 μg/L and changed to 5 to 500 μg/L using CPEB. LoD and LoQ values of standard solution Cu2+ measurement with CPEB were slower than CPE. The Horwitz ratio calculation was smaller than two for both CPE and CPEB. The recovery of Cu2+ standard measure in sample solution as the matrix was obtained 93,49 ± 6,39%. According to the Decree of the Ministry of Health Number, the level of Cu2+ in the tomato sample was found 6.019 ± 0.69 mg/kg, which is over than threshold value of Cu2+ (5 mg/kg) 03725/B/SK/VII/89. 
KINETIKA TRANSFER ION DOPAMIN PADA ANTARMUKA AIR-NITROBENZENA SECARA VOLTAMETRI Nyoman Sudarma; Mrs Irdhawati; James Sibarani
Seminar Ilmiah Nasional Teknologi, Sains, dan Sosial Humaniora (SINTESA) Vol 1 (2018): PROSIDING SINTESA
Publisher : LPPM Universitas Dhyana Pura

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

ABSTRAKPenelitian transfer ion dopamin secara elektrokimia pada antarmuka air-nitrobenzena dengan metode voltametri telah dilakukan. Pengukuran transfer ion ini menggunakan sistem 3 elektroda yaitu 2 elektroda Ag/AgCl sebagai elektroda kerja dan elektroda pembanding, dan elekroda platina sebagai elektroda pembantu.Penelitian diawali dengan pembuatan elektroda pembanding Ag/AgCl yang kemudian dilakukan karakterisasi terhadap elektroda tersebut. Kinetika transfer ion dopamin diketahui dengan melakukan perhitungan nilai potensial standar dan energi bebas Gibbs transfer ion dopamin melalui pengukuran larutan standar dopamin dan tetra metil amonium klorida (TMACl) dengan metode voltametri siklik. Hasil karakterisasi elektroda pembanding Ag/AgCl menunjukkan kelayakan elekroda dengan nilai slope sebesar 60,71 dan r = 0,9984. Potensial standar transfer ion dopamine adalah 0,173 V dan proses berlangsung secara spontan dengan perubahan energi bebas Gibbs (ΔG) sebesar -16,64 kJ/mol.Kata kunci: transfer ion dopamin, antarmuka air-nitrobenzena, voltametriABSTRACTResearch dopamine electrochemical ion transfer at the water-nitrobenzena interface by voltammetry method has been conducted. This measurement uses three electrode system that was two electrode Ag/AgCl electrode as the working electrode and reference electrode, and platinum electrodes as counter electrode. The research comparison begins with the manufacture of electrodes Ag/AgCl were then performed to characterize the electrode. Kinetics of transfer ion dopamine is known to perform calculations potential sandard value and Gibbs energy through measurements the dopamine standard and ammonium chloride and metal tetra (TMACl) solution by cyclic voltammetry method. The results of the reference electrode characterization of Ag/ AgCl electrodes demonstrate the feasibility of the slope value of 60.71 and r = 0.9984. Dopamine standard ion transfer potential is 0.173 V and the process takes place spontaneously with the change in Gibbs free energy (ΔG) of -16.64 kJ/ mol.Keywords: dopamine transfer ion, water-nitrobenzene interface, voltammetry.
Preparation and Validation of Fe2O3 Modified Carbon Paste Electrode for Measurement of Dopamine by Voltammetry Method Irdhawati Irdhawati; Manuntun Manurung; Ni Ketut Yuni Sri Lestari
Jurnal Kimia Sains dan Aplikasi Vol 22, No 6 (2019): Volume 22 Issue 6 Year 2019
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (284.434 KB) | DOI: 10.14710/jksa.22.6.227-234

Abstract

Preparation and validation of the Fe2O3 modified carbon paste electrode have been carried out for the analysis of dopamine by the voltammetry method. Validation parameters of carbon paste electrodes (CPA) tested include linear concentration range, Limit of Detection (LoD), Limit of Quantification (LoQ), accuracy, and selectivity in the presence of ascorbic acid and uric acid. The results obtained in the optimization of the composition and condition of the Fe2O3 modifier in graphite are 0.8% mass at pH 6 solution with the Brinton Robinson buffer solution. The peak potential shifted 32 mV in the negative direction from the initial peak potential of 319 mV at the carbon paste electrode without modification to the peak potential of 287 mV at the 0.8% Fe2O3 modified carbon paste electrode. The linear concentration range at concentrations of 8 µM–100 µM obtained a linear equation y= 1.1204 + 0.1289x with R2=0.99943. LoD value obtained is 0.23 µM, and the LoQ is 0.77 µM. In the selectivity test obtained in the dopamine analysis using 0.8% Fe2O3 modified carbon paste electrode, the anodic peaks of dopamine (75 mV), ascorbic acid (190 mV), and uric acid (200 mV) can be separated. This method has acceptable repeatability because it produces a Horwitz Ratio value of 0.0417, which is smaller than two. Preparation and validation of 0.8% Fe2O3 modified carbon paste electrode can be declared as eligible for the measurement of dopamine.
PATTERN OF POTASSIUM RELEASE FROM SLOW RELEASE FERTILIZER POTASSIUM CLORIDE-BENTONITE FERTILIZER Carver J M; Suarya P; Irdhawati Irdhawati
Jurnal Ilmu Pendidikan Indonesia Vol 11, No 2 (2023): JURNAL ILMU PENDIDIKAN INDONSIA
Publisher : Program Magister Pendidikan IPA, Program Pascasarjana Universitas Cenderawasih

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31957/jipi.v11i2.3074

Abstract

Potassium has an important role in the process of plant growth, but its presence and availability in the soil are limited, because potassium is easily lost and flows out by water. Increasing the efficiency of potassium fertilization can be pursued through the formulation of fertilizer in the form of slow-release fertilizer (SRF) using bentonite.  This study aimed to determine the release of potassium in potassium chloride fertilizer into the soil after bonding with acid-activated bentonite coated with potassium chloride. The composition of the KCl fertilizer made varies with bentonite with a mass ratio (g) of 1:1; 2:1; 3:1; 4:1; and 5:1, with a percolation time of 28 days. The concentration of released potassium was determined using an atomic absorption spectrophotometer. Material characterization was carried out by FTIR. The results showed that the ratio 1:3 had the highest potassium content of 45.12% with an incubation time of 28 days. The concentration of released potassium on day 7; 14; 21; and 28 respectively (12.55±1.25)%, (28.39±1.49)%, (5.,91±0.98)%, and (70.49±1.36)% . The results of the characterization of the determination of the fungal group on SRF3 were not significantly different from that of activated bentonite. Even though there were differences in the intensity of certain peaks and changed the functional groups.