Geração fotoquímica de vapor acoplada a espectrometria de absorção atômica para a determinação de Mercúrio em alimentos para gatos de estimação

• Ano de defesa: 2020
• Autor(a) principal: Silva, Nilvan Alves da
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Mercúrio; Alimentos; Animais; Gatos de estimação; Geração fotoquímica de vapor
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/51403

The Mercury (Hg) has high bioaccumulation in fish and seafood. As fish is one of the main ingredients in commercial pet foods, specifically cats, the Hg content can be worrisome, pose a toxicological risk to the animal and should therefore be investigated. In this work, Total Mercury (THg) concentration was determined in samples of canned food with ingredient based on tuna and seafood for cats using Photochemical Vapor Generation (PVG) coupled with atomic absorption spectrometry. Initially, experimental conditions such as photochemical reactor and gas-liquid separator (GLS) configuration, organic precursor type and concentration for radical generation and Hg photoreduction, UV irradiation time and carrier gas flow were optimized for THg determination. Higher generation of volatile Hg species was obtained through the 19W UV lamp reactor with internal quartz analytical path and using a laboratory produced GLS made of polypropylene tube. Higher PVG efficiency was achieved by using 10% v v-1 formic acid as an organic precursor, 4 seconds of UV irradiation in the sample and carrier gas flow at 50 mL min-1. The calibration curve for the method presented a correlation coefficient greater than 0.99. Accuracy was confirmed using certified reference materials (DOLT-3 and DORM-1), with recovery rates of 93-110%. Precision had a relative standard deviation of less than 5%. Considering the optimized conditions, a detection limit of 0.28 µg kg-1 was obtained. The method for determination of THg was applied to 10 samples of cat food purchased in local market. Concentration in the samples ranged from 0.035 to 0.388 mg kg-1 THg, where the highest concentration was determined in foods with only tuna based ingredient. Only one sample presented concentration close to the limit established by regulatory agency. By calculating the estimated daily intake (EDI), cats would theoretically consume 0.0021 to 0.0233 mg HgT per day per kg body weight, considering the foods analyzed. Thus, none of the samples presented higher value than considered toxic for cats. Therefore, the method used was efficient, simple and low cost for the determination of THg in cat food.