Comparing plastic syringes and disposable columns to extract n-alkanes in forage and concentrate feeds/Comparacao de seringas plasticas e colunas descartaveis para extracao de n-alcanos em forragens e concentrados

Saturated aliphatic hydrocarbons (n-alkanes) were extracted from feed, orts, and bovine fecal samples using disposable, plastic 5mL-syringes as an alternative material to disposable columns, which are normally used in the liquid-solid extraction phase of n-alkanes. For both methods, the n-alkane ext...

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Bibliographic Details
Published in:	Ciência rural Vol. 40; no. 8; pp. 1844 - 1847
Main Authors:	de Oliveira, Dimas Estrasulas, Tedesch, Luis Orlindo
Format:	Journal Article
Language:	English Spanish
Published:	Universidade Federal de Santa Maria 01-08-2010
Subjects:	Analysis análise Chromatography consumo determinação de n-alcanos digestibilidade digestibility hidrocarbonetos hydrocarbons Hypodermic needles Hypodermic syringes intake n-alkane determination Syringes
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Summary:	Saturated aliphatic hydrocarbons (n-alkanes) were extracted from feed, orts, and bovine fecal samples using disposable, plastic 5mL-syringes as an alternative material to disposable columns, which are normally used in the liquid-solid extraction phase of n-alkanes. For both methods, the n-alkane extracts (carbon chain length between 31 and 36 atoms) were identified using gas chromatography. The linear regression between methods were: 1) feces: column Alkane=2.63+0.92^syringeAlkane [[r.sup.2] = 0.94, square root of the mean square error (RMSE) = 13.7mg [kg.sup.-1], n=30] from which the intercept and the slope did not simultaneously differ from zero and unity (P>0.05), respectively; 2) feeds: column Alkane = 0.36 + 1.12 x syringeAlkane ([r.sup.2]=0.85, RMSE=1.9mg [kg.sup.-1], n=21) from which the intercept and the slope did not simultaneously differ from zero and unity (P>0.05), respectively; 3) orts: column Alkane=0.49+0.92^syringeAlkane ([r.sup.2]=0.98, RMSE=1.2mg kg'1, n=15) from which the intercept and the slope did not simultaneously differ from zero and unity (P>0.05), respectively. Materials with low concentration of nalkanes may affect the values obtained in both methods. These results suggested that disposable plastic syringes might be a viable alternative to columns thus, reducing analytical costs. Key words: analysis, digestibility, intake, hydrocarbons, n alkane determination N-alcanos foram extraidos de alimentos, sobras e fezes de bovinos com a utilizacao de seringas plasticas descartaveis de 5mL como um material alternativo as colunas descartaveis que sao normalmente utilizadas para a fase de extracao liquido-solido. Para ambos os metodos, os n-alcanos (cadeias de carbono entre 31 e 36 atomos) foram identificados usando cromatografia gasosa. As regressoes lineares entre metodos foram: 1) fezes: col-una Alcano = 2,63 + 0,92 x seringa Alcano [[r.sup.2] = 0,94, raiz do quadrado medio do erro (RMSE)=13,7mg [kg.sup.-1], n=30], em que o intercepto e o coeficiente angular nao diferiram simultaneamente de zero e um (P>0,05), respectivamente; 2) alimentos: coluna Alcano=0,36+1,12xseringa Alcano ([r.sup.2] = 0,85, RMSE=1,9mg kg1, n=21), em que o intercepto e o coeficiente angular nao diferiram simultaneamente de zero e um (P>0,05), respectivamente; 3) sobras: coluna Alcano=0,49+0,92^seringa Alcano ([r.sup.2]=0,98, RMSE = 1,2mg [kg.sup.-1], n=15), em que o intercepto e o coeficiente angular nao diferiram simultaneamente de zero e um (P>0,05), respectivamente. Materiais com baixas concentracoes de alcanos podem afetar os valores obtidos em ambos os metodos de extracao. Esses resultados sugerem que as seringas plasticas descartaveis podem ser uma alternativa viavel as colunas, reduzindo o custo analitico. Palavras-chave: analise, determinacao de n-alcanos, digestibilidade, consumo, hidrocarbonetos.
ISSN:	0103-8478 1678-4596