Desenvolvimento e validação de um método para determinação de colesterol em farinha de carne e ossos em mistura de alimentos para ruminantes utilizando cromatografia gasosa.

• Ano de defesa: 2007
• Autor(a) principal: Cecilia Muller Bandeira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Encefalopatia espongiforme bovina; ruminante; Análise cromatográfica; Ruminante Alimentação e rações; Espectrometria de massa; Farinha de carne e osso como ração
• Link de acesso: http://hdl.handle.net/1843/VETC-7AXM87

This work aimed at developing and validating a chromatographic method for detection meat and bone meals (MBM) in ruminant feed by cholesterol determination, focusing to avoid the animal contamination with bovine spongiform encephalopathy. Five methods for sample preparation were tested and from these, sample saponification without heating was chosen. The best conditions for saponification and extraction of unsaponified matter were defined using factorial and complete designs with central points. Gas chromatography (CG) was chosen due its higher sensibility and better separation of peak cholesterol at presence of other sterols. Was used polar capillary column of polyetileneglycol 30mx0,25mmx0,25µm and flame ionization detector (FID). GC conditions were: injection 1 µL, insert 260 ºC, column 100 ºC/2min and 260 ºC/48min (15 ºC/min), flow 1,68 mL/min, drag gas hydrogen and FID 300 ºC. Cholesterol was identified by comparison of retention times of the samples and standard and co-chromatography and confirmed by high performance liquid chromatography (HPLC) and mass spectrometry (MS). HPLC parameters: mobile phase acetonitrile:isopropanol (98:02); column C18, 100x 4,6mmx4µm (Chromolith), flow 1 mL/min. MS-MS parameters: íon-trap analyzer, APCI ionization source: 450 °C, positive mode, corona: 4000 nA, dry gas N2: 350°C, flow 5 L/min, nebulizer: 65 psi, MS/MS fragmentation energy 1,4 V, acquisition 100 to 700 (m/z). The method was validated by selectivity, specificity, linearity, detection limit (DL), quantification limit (QL), precision, trueness and robust. Cholesterol peak show excellent resolution and HPLC-MS confirmed specificity. Determination coefficient for linearity evaluation were higher than 0,9997. DL and QL were 0,001 and 0,003 mg/g, respectively. Recovery e variation coefficient (VC) at ruminant feed samples fortified with cholesterol standard (0,01; 0,025; 0,05; 0,1; 0,25 e 0,5 mg/mL) were respectively 84-86,7 % and 2,9-4,0 %. Cholesterol concentrations obtained from ruminant feed and MBM were, respectively 0,02 and 0,4 mg/g. The method show precision, trueness and capacity of detect MBM in ruminant feed by cholesterol determination in concentrations higher than 0,025 mg/g.