A method is presented for the choice of spectral regions when absorption measurements are coupled to chemometric tools to perform quantitative analyses. The method is based on the spectral distribution of the relative standard deviation of concentration (s c/c). It has been applied to the development of PLS-FTNIR calibration models for the determination of density and MON of gasoline, and ethanol content and density of ethanol fuel. The new method was also compared with the correlation (R²) method and has proved to generate PLS calibration models that present better accuracy and precision than those based on R².

Foram dosados compostos fenólicos por cromatografia líquida de alta eficiência em aguardente de cana estocada por seis meses em barris de 20 L, das madeiras brasileiras amburana - Amburana cearensis (Fr. All.) A.C. Smith; bálsamo - Myroxylon peruiferum L.F.; jequitibá Cariniana estrellensis (Raddi) Kuntze; jatobá - Hymenaea spp; ipê - Tabebuia spp e carvalho europeu - Quercus sp. Constatou-se que cada madeira introduziu predominantemente compostos fenólicos específicos na bebida: a) ácidos elágico e vanílico no carvalho; b) ácido vanílico e sinapaldeído na amburana; c) vanilina e ácido elágico no bálsamo; d) ácido gálico no jequitibá, e) coniferaldeído no jatobá e f) ácidos siríngico e vanílico e coniferaldeído no ipê.

The phenolic constituents were determined by high performance liquid chromatographic in sugar cane spirits stored for six months in casks of 20 L, of the brasilian woods "amburana" - Amburana cearensis (Fr. All.) A.C. Smith; "bálsamo" - Myroxylon peruiferum L.F.; "jequitibá" - Cariniana estrellensis (Raddi) Kuntze; "jatobá" - Hymenaea spp; "ipê" - Tabebuia spp and of the european oak - Quercus sp. A predominance of the phenolic constituents of each wood was observed in the beverage: a) ellagic and vanillic acid in oak; b) sinapaldehyde and vanillic acid in "amburana"; c) vanillin and elagic acid in "balsamo"; d) gallic acids in "jequitibá"; e) coniferaldehyde in "jatobá" e f) coniferaldehyde, vanillic and syringic acids in "ipé".

A madeira de Vouacapoua pallidior (Leguminosae-Caesalpinioideae) contém (+)-vouacapenato de metila.

Thz wood of Vouacapoua pallidior (Leguminosae-Caesalpinioideae) Contains (+)-methyl vouacapenate.

Resumo Do extrato etanólico da madeira de tronco de Tachigalia paniculata Ducke (Leguminosae-Caesalpinioideae) foram isoladas quantidades substanciais de ácido 2-(3-indolil)-acético.

Abstract The ethanolic extract of trunk wood of Tachigalia paniculata Ducke (Leguminosae-Caesalpinioideae) was found to contain substantial quantities of 2-(3-indolyl)-acetic acid.