Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol)
Formaldehyde is used as preservative in fish by fisherman, in order to maintain its fresh look and prevent microbial spoilage, is a big risk to consumer’s health. Formaldehyde is carcinogenic. Thus a simple, sensitive and rapid device for its determination is necessary based on electrochemical biose...
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| Format: | Thesis |
| Language: | English English |
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2016
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| Online Access: | https://eprints.ums.edu.my/id/eprint/39315/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/39315/2/FULLTEXT.pdf |
| _version_ | 1825715681599946752 |
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| author | Noor Aini Bohari |
| author_facet | Noor Aini Bohari |
| author_sort | Noor Aini Bohari |
| collection | UMS |
| description | Formaldehyde is used as preservative in fish by fisherman, in order to maintain its fresh look and prevent microbial spoilage, is a big risk to consumer’s health. Formaldehyde is carcinogenic. Thus a simple, sensitive and rapid device for its determination is necessary based on electrochemical biosensor coupled with an enzyme and formaldehyde dehydrogenase (FDH). A novel electrochemical biosensor was developed by depositing an ionic liquid (IL) (e.g., 1-ethyl-3-methylimidazolium trifluoromethanesulfonate; [EMIM][Otf]), ZnO nanoparticles (ZnONPs), CaO nanoparticles (CaONPs), Au nanoparticles (AuNPs) and chitosan (CHIT) on a glassy carbon electrode (GCE) for determination of formaldehyde in fish. The enzyme requires ß-nicotinamide adenine dinucleotide (NAD+) as a cofactor which is then reduced to NADH during enzymatic reaction. Formaldehyde Dehydrogenase (FDH) was immobilized through the entrapment technique and measured based on the reduction of NAD+ under a potential of 0.4 V. The morphological characteristics of microstructures of CHIT, NPs/[EMIM][Otf]/CHIT and FDH/NPs/[EMIM][Otf]/CHIT were observed under scanning electron microscopy (SEM). Methylene blue was used as a redox indicator to increase in the electron transfer capacity and stable in both the redox reaction. The enzyme electrode showed optimum response when operated at 250C in 50 mM Tris-HCl buffer, pH 6.5 within 5 s. The storage stability was done for 5 weeks. A relative standard deviation for the slopes of 0.32% (n = 5) was obtained for reproducibility. Under the optimal conditions, the FDH/AuNPs/[EMIM][Otf]/CHIT/GCE was showed wider linear range of formaldehyde concentrations from 0.01 to 10 ppm within 5 s, with the detection limit of 0.1 ppm. The FDH/AuNPs/[EMIM][Otf]/CHIT was found more sensitive than FDH/ZnONPs/[EMIM][Otf]/CHIT and FDH/CaONPs/[EMIM][Otf]/CHIT. FDH/AuNPs/[EMIM][Otf]/CHIT was used for the detection of formalin on-site in fish sample; Lutjanus malabaricus and Thunnus tonggol which were found below the safety level (5 ppm). The developed biosensor is a simple, rapid, economically, highly efficient, and high accuracy when compared to the existing technique. |
| first_indexed | 2024-09-24T00:50:42Z |
| format | Thesis |
| id | ums.eprints-39315 |
| institution | Universiti Malaysia Sabah |
| language | English English |
| last_indexed | 2024-09-24T00:50:42Z |
| publishDate | 2016 |
| record_format | dspace |
| spelling | ums.eprints-393152024-07-31T03:56:26Z https://eprints.ums.edu.my/id/eprint/39315/ Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol) Noor Aini Bohari TP1-1185 Chemical technology Formaldehyde is used as preservative in fish by fisherman, in order to maintain its fresh look and prevent microbial spoilage, is a big risk to consumer’s health. Formaldehyde is carcinogenic. Thus a simple, sensitive and rapid device for its determination is necessary based on electrochemical biosensor coupled with an enzyme and formaldehyde dehydrogenase (FDH). A novel electrochemical biosensor was developed by depositing an ionic liquid (IL) (e.g., 1-ethyl-3-methylimidazolium trifluoromethanesulfonate; [EMIM][Otf]), ZnO nanoparticles (ZnONPs), CaO nanoparticles (CaONPs), Au nanoparticles (AuNPs) and chitosan (CHIT) on a glassy carbon electrode (GCE) for determination of formaldehyde in fish. The enzyme requires ß-nicotinamide adenine dinucleotide (NAD+) as a cofactor which is then reduced to NADH during enzymatic reaction. Formaldehyde Dehydrogenase (FDH) was immobilized through the entrapment technique and measured based on the reduction of NAD+ under a potential of 0.4 V. The morphological characteristics of microstructures of CHIT, NPs/[EMIM][Otf]/CHIT and FDH/NPs/[EMIM][Otf]/CHIT were observed under scanning electron microscopy (SEM). Methylene blue was used as a redox indicator to increase in the electron transfer capacity and stable in both the redox reaction. The enzyme electrode showed optimum response when operated at 250C in 50 mM Tris-HCl buffer, pH 6.5 within 5 s. The storage stability was done for 5 weeks. A relative standard deviation for the slopes of 0.32% (n = 5) was obtained for reproducibility. Under the optimal conditions, the FDH/AuNPs/[EMIM][Otf]/CHIT/GCE was showed wider linear range of formaldehyde concentrations from 0.01 to 10 ppm within 5 s, with the detection limit of 0.1 ppm. The FDH/AuNPs/[EMIM][Otf]/CHIT was found more sensitive than FDH/ZnONPs/[EMIM][Otf]/CHIT and FDH/CaONPs/[EMIM][Otf]/CHIT. FDH/AuNPs/[EMIM][Otf]/CHIT was used for the detection of formalin on-site in fish sample; Lutjanus malabaricus and Thunnus tonggol which were found below the safety level (5 ppm). The developed biosensor is a simple, rapid, economically, highly efficient, and high accuracy when compared to the existing technique. 2016 Thesis NonPeerReviewed text en https://eprints.ums.edu.my/id/eprint/39315/1/24%20PAGES.pdf text en https://eprints.ums.edu.my/id/eprint/39315/2/FULLTEXT.pdf Noor Aini Bohari (2016) Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol). Masters thesis, Universiti Malaysia Sabah. |
| spellingShingle | TP1-1185 Chemical technology Noor Aini Bohari Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol) |
| title | Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol) |
| title_full | Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol) |
| title_fullStr | Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol) |
| title_full_unstemmed | Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol) |
| title_short | Development of electrochemical biosensor for determination of formalin in fish samples; malabar red snapper (lutjanus malabaricns) and longtail tuna (thunus tonggol) |
| title_sort | development of electrochemical biosensor for determination of formalin in fish samples malabar red snapper lutjanus malabaricns and longtail tuna thunus tonggol |
| topic | TP1-1185 Chemical technology |
| url | https://eprints.ums.edu.my/id/eprint/39315/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/39315/2/FULLTEXT.pdf |
| work_keys_str_mv | AT noorainibohari developmentofelectrochemicalbiosensorfordeterminationofformalininfishsamplesmalabarredsnapperlutjanusmalabaricnsandlongtailtunathunustonggol |