The study of ascorbic acid as a reducing agent for iron(III) has been investigated in order to obtain an alternative carcinogenic reducing agent, hydroxylamine, used in spectrophotometric standard method based on the formation of a red-orange complex of Fe(II)-o-phenanthroline. The study was optimised with regards to ascorbic acid concentration as well as pH solution. The results showed that ascorbic acid showed maximum capacity as reducing agent of iron(III) under concentration of 4.46.10 -4 M and pH solution of 1-4.Under these conditions, ascorbic acid reduced iron(III) proportionally and performed similarly to that of hydroxylamine. The method gave result to linear calibration over the range of 0.2-2 mg/L withhigh accuracy of 97 % and relative standard deviation of less than 2 %. This method was successfully applied to assay iron speciation in water samples.Keyword: Iron, speciation, ascorbic acid, o-phenanthroline, spectrophotometry INTRODUCTIONIron is the second most abundant metallic element in the earth's crust and is essential in the metabolism of plants and animals. If presented in excessive amounts; however, it forms oxyhydroxide precipitate that stains laundry and porcelain. As a result, the recommended limit for iron in domestic water supplies is 0.3 mg/L. 1 Determination of Fe(II) and Fe(III) is important in many natural sciences like geology, agriculture, biology or environmental protection, mainly on account of different bioavailability and metabolism of iron on its two oxidation states. Iron(II) is essential for good health, as it helps transport oxygen in the blood and storage of oxygen by means of haemoglobine and myoglobine.2 Iron deficiency may lead to low immunity and infectious diseases. If the human body takes in too much iron will cause excretory functional disturbance and likely have greater carcinogenic potential. Both Fe (II) and Fe(III) are important in the biosphere, serving as an active centre of a wide range of proteins such as oxidases, reduces and dehydrates.3 However the plants need a certain amount of iron(II) to survive. Iron helps them create chlorophyll and aids in several other chemical processes plants perform. However, too much iron can have a toxic effect on the plant, weakening and eventually killing it. It should be noted that plants only absorb ferrous iron particles from the soil, and that other forms of iron will not affect plants.
This research has investigated adsorption of Fe with using fly ash adsorbent. Phase of adsorption of Fe is activated with H 2 SO 4 after that the fly ash were characterized by using XRF, FTIR and SEM. Determination of optimum conditions on the adsorption of Fe with adsorbent mass variations, variations in contact time, pH variation and variation concentration and adsorption isotherm study. Resulth show that the adsorption of Fe in optimum condition occurs in adsorbent mass of 2.5 g, for 60 minutes contact time with pH 4 at a concentration of 20 ppm. The results also able to adsorp up to 94% Fe. The adsorption of Fe with using fly ash adsorbent was more fitted to the Langmuir model than to Freundlich model.
A coated-wire ion selective electrode (CWISE) based on chitosan as a carrier for detection of chromate, was developed. CWISE has easy measurement for field analysis, good selectivity and sensitivity. The CWISE's membrane consist of mixture an active material of chitosan, aliquat 336-chromate, polyvinylchloride (PVC) and dioctylphtalate (DOP) as plasticizer = 4:0.5:35:60.5 (% w/w) dissolved in tetrahydrofuran (THF) solvent (1:3 w/v). The electrode exhibited a good Nernstian slope of 29.77±0.03 mV/decade and a linear concentration range from 10 -6 to 10 -1 M for chromate. The limit of detection was 1.862 x 10 -6 M. It had response time of 20 -40 sec, and could be used for 49 days. This chromate selective-electrode was found more selective towards the chromate ion than other anions, useable in pH range of 5.0 -9.0 and temperature of 20 -50 o C. It was applied as an electrode for direct determination of chromate in water samples and their result compared to standard spectrophotometric method.
Research of speciation analysis Cr(III) and Cr(VI) using hypochlorite oxidants with visible spectrophotometry has been proposed. This research was carried to obtain optimum conditions of oxidation process Cr(III) into Cr(VI) and the formation of Cr(VI)-Diphenylcarbazide complex to the wavelength, complexing time, oxidizing agent (oxidant) concentration, oxidation temperature, pH, and the influence of foreign ion, so it can be proposed as an alternative method for speciation analysis of Cr(III) and Cr(VI). Optimization results show that the maximum wavelength of Cr(VI)-diphenylcarbazide complex is 542 nm by the stable complex time 16-30 minutes using a hypochlorite (HOCl) oxidant concentration 1 x 10 -3 M, temperature 60 o C and pH 1. This method is compared with standard method. The presently developed method is more simple and faster than standard method. Regarding accuracy and precision, the method is quite comparable with the standard methods.
Naskah yang diajukan oleh penulis harus diketik dengan komputer menggunakan bahasa Indonesia yang baik dan benar, menyertakan 1 (satu) soft copy dalam bentuk CD. Penulisan memakai program Microsoft Word dengan ukuran kertas A4, jarak 1,15 spasi. Naskah yang diajukan oleh penulis merupakan naskah asli yang belum pernah diterbitkan maupun sedang dalam proses pengajuan ditempat lain untuk diterbitkan, dan diajukan minimal 1 (satu) bulan sebelum penerbitan. B. Format Penulisan Artikel Judul Judul ditulis dengan huruf besar, nama penulis tanpa gelar, mencantumkan instansi asal, e-mail dan ditulis dengan huruf kecil menggunakan huruf Times new Roman 11. Abstrak Abstrak ditulis dalam bahasa Indonesia antara 100-250 kata, dan berisi pernyataan yang terdapat dalam isi tulisan, menyatakan tujuan dari penelitian, prosedur dasar (pemilihan objek yang diteliti, metode pengamatan dan analisis), ringkasan isi dan kesimpulan dari naskah menggunakan huruf Time New Roman 11, spasi 1,15. Kata Kunci Minimal 3 (tiga) kata kunci ditulis dalam bahasa Indonesia Isi Naskah Naskah ditulis menggunakan huruf Times New Roman 11. Penulisan dibagi dalam 5 (lima) sub judul, yaitu Pendahuluan, Kajian Pustaka, Metode Penelitian, Hasil Pembahasan dan Kesimpulan. Penulis menggunakan standar Internasional (misal untuk satuan tidak menggunakan feet tetapi meter, menggunakan terminalogi dan simbol diakui international (Contoh hambatan menggunakan simbol R). Bila satuan diluar standar SI dibuat dalam kurung (misal = 1 Feet (m)). Tidak menulis singkatan atau angka pada awal kalimat, tetapi ditulis dengan huruf secara lengkap, Angka yang dilanjutkan dengan simbol ditulis dengan angka Arab, misal 3cm, 4kg. Penulis harus secara jelas menunjukkan rujukan dan sumber rujukan secara jelas. iv Daftar Pustaka Rujukan / Daftar pustaka ditulis dalam urutan angka, tidak menurut alpabet, dengan ketentuan seperti dicontohkan sbb : 1. Standar Internasional : IEC 60287-1-1 ed2.0; Electric cables-Calculation of the current rating-Part 1-1 : Current rating equations (100% load factor) and calculation of losses-General.
Imunisasi pada bayi merupakan tindakan yang dapat menimbulkan trauma karena hal tersebut dapat menyebabkan nyeri. Salah satu teknik menejemen nyeri non-farmakologi adalah dengan pemberian ASI. Tujuan dari penelitian ini adalah untuk mengetahui efektifitas pemberian ASI terhadap penurunan respon nyeri pada bayi yang dilakukan imunisasi Pentavalen. Penelitian menggunakan metode Quasi Eksperimen dengan static group comparation dan teknik pengambilan sampel menggunakan consecutive sampling, jumlah sampel didapatkan 54 responden. Penelitian ini dilakukan di Puskesmas Sawah Lebar Kota Bengkulu pada tanggal 11 September – 10 Oktober 2017. Analisis perbedaan respon nyeri menggunakan Independent Sample t-Test. Hasil penelitian ini menunjukkan rata-rata respon nyeri pada bayi pada kelompok intervensi adalah 3,89. Sedangkan pada kelompok kontrol rata-rata tingkat nyerinya adalah 7.63. Hasil analisis bivariat menunjukkan ada perbedaan rata-rata respon nyeri pada bayi yang diberikan ASI (intervensi) dengan bayi yang diberikan terapi sentuhan (kontrol) pada saat dilakukan penyuntikan imunisasi Pentavalen sebesar 3,74 (p=0,000). Diharapkan bagi Puskesmas khususnya petugas imunisasi dapat menerapkan prinsip menurunkan respon nyeri pada bayi yang diimunisasi yaitu dengan melakukan intervensi pemberian ASI sebelum dan sesudah dilakukan penyuntikkan imunisasi pada bayi yang merupakan salah satu Asuhan Sayang Bayi.
<em>On the production floor CV. There are 6 work stations that produce wooden dollhouses. All activities carried out by workers are carried out simply with irregular production floors where workers put the tools and materials used out of place which causes the workspace to be more narrow and work risks arise. To correct this, an analysis of the work environment will be carried out using 5S. The formulation of the problem is done through observations made on the production floor CV. RB. The review is carried out on the current work environment layout and the problems that occur in it. The identification results are used as a basis for compiling the concept of applying 5S in accordance with the characteristics of the production floor CV. RB. Analysis of the impact caused by the existing conditions is the result of observations and interviews with relevant parties. Furthermore, this research will give a proposal to solve the problems in the production of dollhouses using 5S. One of the improvements made is the provision of training on the basic concepts of 5S. By using 5S there will be improvements where workers will become disciplined, reduce waste and work risks.</em>
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.