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|Type:||Artigo de periódico|
|Title:||Rapid determination of nitrites in food using a diffuse UV-visible reflectance method|
|Abstract:||A simple, low-cost, sensitive and selective method for the determination of trace quantities of nitrite in foods such as cheese and cured meat using diffuse ultraviolet-visible reflectance was developed. It is based on the reaction of nitrite with sulphadiazine and alpha-naphthol, which produces a coloured product in basic medium. The reaction is carried out directly in the measuring cell. For cheese the limit of detection (LOD), expressed as NaNO2, was estimated to be about 2.0 x 10(-2) mg l(-1) (2.9 x 10(-7) mol l(-1)) in the final measuring solution and 0.17 mg kg(-1) in cheese (2.5 x 10(-6) mol kg(-1)). The relative standard deviation (RSD) varied from 5% to 8% depending on the sample. For meat the LOD was estimated to be about 2.0 x 10(-2) mg l(-1) (2.9 x 10(-7) mol l(-1)) in the final measuring solution and 0.13 mg kg(-1) in meat (1.9 x 10(-6) mol kg(-1)). The RSD varied from 3% to 6% depending on the sample. The results of the proposed method were also compared with those obtained with the official method using the statistical Student's t-test and F-test procedures.|
|Editor:||Taylor & Francis Ltd|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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