Low-Temperature Digestion Method for Fish Tissue and Sediment Prior to Total Mercury Analysis

Using high-pressure teflon bomb digestion in phosphorus determination of aquatic animals

“…For digestion, a combination of sulphuric acid and nitric acid is proven as an effective tool (Brown et al, 1973;Sadiq and Zaidi, 1983;Colina et al, 1996), whilst higher pressure of a closed and heated system has a strong positive influence on the digestion of persistent materials (Schnitzer et al, 1995). Scientists use various digestion protocols for the same sample types and the results may not be comparable among procedures.…”

Evaluation of some procedures relevant to the determination of trace elemental components in biological materials by destructive neutron activation analysis

“…Under these conditions, the organic matrix is theoretically oxi dized primarily to carbon dioxide and gaseous water, which are removed from the system leaving behind a mineral product which should be soluble in an appropriate solvent, typically an aqueous acid. There is general agreement that such a procedure results in the loss of the more volatile components (^.e., arsenic, selenium, mercury, and halogens) from biological samples (107-109)* Evidence suggests that for some elements, the volatile forms indigenous to the samples can be converted to less volatile mineralized forms via the application of ashing aids, such as magnesium nitrate and sulfuric acid, and low levels of heat (preashing) prior to the imposition of the harsher conditions required for ashing (109)(110)(111)(112)(113)(114)(115)(116)(117)(118)(119)(120)(121)(122)(123) • Pre-ashing has been accomplished through the use of a temperature programmed furnace and by starting with a cold furnace which allows a slow increase to ashing temperature (110)(111)(112). One of the most successful applications of the pre-ashing technique was reported by LeBlanc and Jackson who obtained quanti tative recoveries of arsenic from fish tissue by pre-ashing with an infra-red lamp, followed by ashing at 500°C in a muffle furnace (112).…”

Determinação de contaminantes inorganicos em latex utilizando espectrometria atomica

“…Digestão ácida (baixa temperatura) (24) • Pesou-se aproximadamente 1 g de amostra (com precisão de 0,1 mg), adicionou-se 10 mL de água, 5 mL de ácido sulfúrico concentrado, 2,5 mL de ácido nítrico concentrado e 10 mL de solução de permanganato de potássio 7,5% m/v. Após 15 minutos, adicionou-se 5 mL de solução de persulfato de potássio 8 % m/v.…”

“…A Tabela 8 mostra os resultados obtidos com os diferentes métodos para a digestão da amostra de PVAc, expressos como recuperação dos analitos adicionados e os respectivos desvios padrão relativos. O procedimento de digestão ácida a baixa temperatura (24) utiliza vários reagentes oxidantes para a degradação da matéria orgânica, empregando-se um aquecimento de, no máximo, 70°C, para que não ocorra a perda das espécies mais voláteis, como Hg. No entanto, como a matriz utilizada é de difícil digestão, foi necessário um tempo de tratamento da amostra de 24 horas e, mesmo após esse período, verificou-se a presença de resíduo carbonizado, o qual foi filtrado.…”