Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode
The illegal adulteration of infant milk powder with melamine in China has resulted in chronic kidney and urinary tract failure in September 2008. To date, several analytical methods have been developed. Unfortunately, the existing methods are complicated, time consuming and costly. In this study, a...
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| Format: | Thesis |
| Language: | English English |
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2015
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| Online Access: | https://eprints.ums.edu.my/id/eprint/42979/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/42979/2/FULLTEXT.pdf |
| _version_ | 1825716130799419392 |
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| author | Rovina Kobun |
| author_facet | Rovina Kobun |
| author_sort | Rovina Kobun |
| collection | UMS |
| description | The illegal adulteration of infant milk powder with melamine in China has resulted in chronic kidney and urinary tract failure in September 2008. To date, several analytical methods have been developed. Unfortunately, the existing methods are complicated, time consuming and costly. In this study, a novel electrochemical sensor method was developed based on the modification of gold electrode with chitosan, nanoparticles and an ionic liquid for determination in the presence of melamine. Three different nanoparticles were used, namely, zinc oxide nanoparticles (ZnONPs), calcium oxide nanoparticles (CaONPs) and gold nanoparticles (AuNPs) which nanoparticles able to detect a low concentration of melamine and cost effecftive. Combining the advantages of chitosan, metal nanoparticles and ionic liquid, the hybrid nanomaterials were effectively enhanced electron-transfer and promoted the current response of melamine ion. Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behaviour with modified gold electrode using methylene blue as a redox indicator for increasing the electron transfer in electrochemical cell. The morphological characteristics of nanomaterials were observed under scanning electron microscope and transmission electron microscope. The gold electrode showed optimum response when operated at 25 ±1 oC in 50 mM Tris–HCl buffer, pH 7 and scan rate of 0.3 V/s within 30 sec. Potential peak currents were found increasing in the order of AuE> AuE/CHIT/NPs > AuE/CHIT/NPs/[EMIM][Otf]. Under optimal conditions, differential pulse voltammetry detected a wide linear range of melamine concentrations with limit of detection 4.0 x 10-14 M for AuE/CHIT/ZnONPs/[EMIM][Otf], 6.2 x 10-16 M for AuE/CHIT/CaONPs/[EMIM][Otf], and 8.0 x 10-18 M for AuE/CHIT/AuNPs/[EMIM][Otf], respectively. The results are suggested that the AuE/CHIT/AuNPs/[EMIM][Otf] is fast, efficient, and wider detection limit. The modified gold electrode was successfully applied for determination of melamine in pretreated milk powder product. The proposed method is fast and simple preparation procedures for analysing the melamine level. The developed method is more convenient based on practical and able to replace the traditional methods subsequently prevent any outbreak of kidney disease. |
| first_indexed | 2025-03-05T01:36:22Z |
| format | Thesis |
| id | ums.eprints-42979 |
| institution | Universiti Malaysia Sabah |
| language | English English |
| last_indexed | 2025-03-05T01:36:22Z |
| publishDate | 2015 |
| record_format | dspace |
| spelling | ums.eprints-429792025-03-03T23:48:18Z https://eprints.ums.edu.my/id/eprint/42979/ Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode Rovina Kobun QD71-142 Analytical chemistry The illegal adulteration of infant milk powder with melamine in China has resulted in chronic kidney and urinary tract failure in September 2008. To date, several analytical methods have been developed. Unfortunately, the existing methods are complicated, time consuming and costly. In this study, a novel electrochemical sensor method was developed based on the modification of gold electrode with chitosan, nanoparticles and an ionic liquid for determination in the presence of melamine. Three different nanoparticles were used, namely, zinc oxide nanoparticles (ZnONPs), calcium oxide nanoparticles (CaONPs) and gold nanoparticles (AuNPs) which nanoparticles able to detect a low concentration of melamine and cost effecftive. Combining the advantages of chitosan, metal nanoparticles and ionic liquid, the hybrid nanomaterials were effectively enhanced electron-transfer and promoted the current response of melamine ion. Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behaviour with modified gold electrode using methylene blue as a redox indicator for increasing the electron transfer in electrochemical cell. The morphological characteristics of nanomaterials were observed under scanning electron microscope and transmission electron microscope. The gold electrode showed optimum response when operated at 25 ±1 oC in 50 mM Tris–HCl buffer, pH 7 and scan rate of 0.3 V/s within 30 sec. Potential peak currents were found increasing in the order of AuE> AuE/CHIT/NPs > AuE/CHIT/NPs/[EMIM][Otf]. Under optimal conditions, differential pulse voltammetry detected a wide linear range of melamine concentrations with limit of detection 4.0 x 10-14 M for AuE/CHIT/ZnONPs/[EMIM][Otf], 6.2 x 10-16 M for AuE/CHIT/CaONPs/[EMIM][Otf], and 8.0 x 10-18 M for AuE/CHIT/AuNPs/[EMIM][Otf], respectively. The results are suggested that the AuE/CHIT/AuNPs/[EMIM][Otf] is fast, efficient, and wider detection limit. The modified gold electrode was successfully applied for determination of melamine in pretreated milk powder product. The proposed method is fast and simple preparation procedures for analysing the melamine level. The developed method is more convenient based on practical and able to replace the traditional methods subsequently prevent any outbreak of kidney disease. 2015 Thesis NonPeerReviewed text en https://eprints.ums.edu.my/id/eprint/42979/1/24%20PAGES.pdf text en https://eprints.ums.edu.my/id/eprint/42979/2/FULLTEXT.pdf Rovina Kobun (2015) Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode. Masters thesis, Universiti Malaysia Sabah. |
| spellingShingle | QD71-142 Analytical chemistry Rovina Kobun Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode |
| title | Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode |
| title_full | Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode |
| title_fullStr | Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode |
| title_full_unstemmed | Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode |
| title_short | Electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode |
| title_sort | electrochemical based sensor for determination of melamine by nanoparticles and ionic liquid modified electrode |
| topic | QD71-142 Analytical chemistry |
| url | https://eprints.ums.edu.my/id/eprint/42979/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/42979/2/FULLTEXT.pdf |
| work_keys_str_mv | AT rovinakobun electrochemicalbasedsensorfordeterminationofmelaminebynanoparticlesandionicliquidmodifiedelectrode |