#TITLE_ALTERNATIVE#
Heavy metals are an element that is widespread distributed in the environment and <br /> <br /> <br /> <br /> <br /> <br /> a few of these metals are essential to life. However, abnormal level of them has <br /> <br /> <br /> <b...
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| Format: | Dissertations |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/23995 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Heavy metals are an element that is widespread distributed in the environment and <br />
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a few of these metals are essential to life. However, abnormal level of them has <br />
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been associated with the toxicity for a human being. Lead (Pb), cadmium (Cd), <br />
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mercury (Hg), tin (Sn), arsenic (As), and copper (Cu) are several heavy metals <br />
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which can contaminate food and drinking water. As the result, they have a <br />
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maximum allowable level in food and drinking water. Numerous analytical <br />
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methods have been developed for their detection with atomic absorption <br />
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spectroscopy (AAS) and inductively coupled plasma mass spectrometry (ICPMS) <br />
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being the most common. While AAS and ICPMS are sensitive and selective, they <br />
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require expensive instrumentation, highly trained personnel and cannot be used for <br />
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on-site analysis. Therefore, analytical methods for metals analysis that are simple, <br />
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portable, and reliable are still needed. <br />
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Colorimetric methods for metal detections have shown great potential in this field. <br />
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This method can simply, conveniently and most importantly can observe by the <br />
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naked eye. Porphyrin derivative compound has been widely used in analytical <br />
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chemistry as chromogenic reagents for metal ion detection. Recently, porphyrin <br />
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derivative compounds have been developed as optical sensors for metal detections. <br />
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One of the most common detection motif used in μPADs is a colorimetric method <br />
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using specific reagents to identify and quantify analytes in the sample. In this work, <br />
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a distance-based μPADs has been developed using porphyrin derivative as the <br />
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colorimetric reagent for metal detection. <br />
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As preliminary study, interaction of three cationic porphyrins: meso-tetrakis(Nmethylpyridinium- <br />
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4-yl)porphyrin (TMPyP), meso-tetrakis(1,3- <br />
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dimethylimidazolium-2-yl)porphyrin (TDMImP), and meso-tetrakis(1,2- <br />
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dimethylpyrazolium-4-yl)porphyrin (TDMPzP) with metals ion (Pb, Cd, Hg, Sn, <br />
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As, dan Cu) have been performed computationally using DFT method. DFT global <br />
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chemical reactivity descriptors were calculated and used to predict their relative <br />
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stability and reactivity. The result shows that M-TDMPzP has the highest chemical <br />
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hardness and the lowest electrophilicity compare to M-TMPyP and M-TDMImP, <br />
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iv <br />
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indicating reaction of TDMPzP with metals will form a more stable complex. <br />
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TDMPzP was continued to synthesized. <br />
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TDMPzP was synthesized using Adler method in a salt form. A pure deep purple <br />
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microcrystalline solid with yield 96,8% was obtained. This compound is soluble in <br />
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water and analysis using UV-Vis spectrophotometry, NMR, and elemental analysis <br />
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was performed for characterization. <br />
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The characterization of the interaction of TDMPzP with metal ions was investigated <br />
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by adding various kind of metals ion to the TDMPzP solution at different pH values. <br />
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The colorimetric sensing ability of TDMPzP indicates that it was selective for Cu2+ <br />
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detection in pH 2-4. Job’s Plot analysis suggest that a stoichiometry of TDMPzPCu <br />
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complex is 1:1 with binding constant 4,15 x 105 M-1. <br />
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The selectivity of TDMPzP for Cu2+ in acidic solution makes it a good candidate to <br />
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be applied in developing a distance-based μPADs for Cu2+. The lower measurable <br />
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limit for this distance-based measurement for Cu2+ detection was at 1 mg L-1 which <br />
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is in accordance with the regulation by US EPA and WHO guidelines for drinking <br />
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water quality. The interference study results indicate the selectivity of μPADs to <br />
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Cu2+ over other metal ions. Application of this system for real drinking water <br />
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sample showed a good agreement between distance-based μPADs with ICP-MS. <br />
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The recoveries were obtained with relative standard deviations of less than 10% <br />
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All of these results suggest that TDMPzP as a colorimetric reagent was successfully <br />
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applied on distance-based μPADs for determination of Cu2+ in drinking water <br />
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samples. This method is simple, rapid, cost-effective, instrument-free, and selective <br />
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for on-site Cu2+ analysis in aqueous medium |
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