New Analytical Methods For The Determination Of Aflatoxins In Food

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dc.contributor.authorShuib, Nor Shifa
dc.date.accessioned2018-01-15T07:16:36Z
dc.date.available2018-01-15T07:16:36Z
dc.date.issued2017-08
dc.description.abstractThis thesis focuses on the development and validation of new analytical methods for the determination of aflatoxins (AFs). Initially, a survey on aflatoxin M1 (AFM1) levels in milk was carried out where 102 fresh milk and 45 human milk samples were analyzed using a standard method. Four samples were contaminated with AFM1, three exceeded the European Community regulatory limit. None of the human milk samples were found to be contaminated with AFM1. Additionally, a new derivatization method for the determination of AFM1 in milk using post column photochemical derivatization was developed. The photochemical derivatization unit was placed between the injector and fluorescence detector (FLD). The samples were first extracted and clean–up using the immunoaffinity AFLATEST column originally targeted for aflatoxins B1, B2, G1 and G2. Then after evaporation/reconstitution step, the injected sample (25 μL) was passed through the photochemical derivatization unit and AFM1 was irradiated by a UV lamp (λ = 254 nm). The amplified signal was detected by the FLD at 365 nm (excitation) and 440 nm (emission), respectively. Significant enhancement of chromatographic responses (66 % area enhancement) of AFM1 after the photochemical derivatization was found. An analytical method for the simultaneous determination of aflatoxins (B1, B2, M1 and M2) in milk using a new sample pretreatment technique, the in-syringe dispersive micro-solid phase extraction (ISDμSPE), coupled with high performance liquid chromatography (HPLC) with FLD was also described. On-line photo-chemical derivatization was used to enhance the detection of aflatoxin B1. Several parameters such as type (XAD-2, Oasis HLB and C-18) and mass of sorbent, vortex speed, vortex time and elution solvent were evaluated. The technique was further validated for rice and peanut samples. Satisfactory results for recovery were obtained within the range of 89.6 – 103.3%. LOQ of 0.003, 0.001, 0.1 and 0.004 μg L-1 for aflatoxins B1, B2, M1 and M2 respectively were obtained. The above developed procedures were applied to real samples. Thirty three samples were analyzed using photo chemical derivatization method. AFM1 were found in goat and cow milk. However, the contaminated samples were lower than the EU regulatory limit (0.05 μg L-1). Of the twenty samples of milk that were treated using ISDμSPE, two were contaminated with AF that were below the Malaysian and European legislation limits. In the case of peanut, two samples were detected with AFB1 and AFB2. However, AFs were not detected in rice and human milk.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/5386
dc.language.isoenen_US
dc.publisherUniversiti Sains Malaysiaen_US
dc.subjectNew analytical methods foren_US
dc.subjectthe determination of aflatoxinsen_US
dc.titleNew Analytical Methods For The Determination Of Aflatoxins In Fooden_US
dc.typeThesisen_US
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