This study aims at identifying and discriminating gunshot residue (GSR) from conventional ammunition of six different calibers by total reflection X-ray fluorescence (TXRF) and pattern recognition by principal component analysis (PCA). GSR samples were collected from hands of volunteer shooters with swabs moistened with deionized water and were extracted with 5% v v-1 nitric acid. Aliquots were deposited on quartz disks for further determination by TXRF of the elements Al, S, Ca, K, Mn, Fe, Ni, Cu, Zn, Br, Sr, Sb, Ba and Pb, whose concentrations were imported into the MATLAB® software for PCA execution. The method proved to be adequate for identification of one- and three-shot residue inorganic components from .40, 9 mm, .380, .38 and .308 calibers, and of three-shot residues from .32 caliber, as well as for sample discrimination as a function of the conventional ammunition calibers studied.

A grande variedade de angiospermas apontou a necessidade do desenvolvimento de sistemas de classificação botânica apoiada pela fitoquímica, bioquímica e outras. Recentemente, técnicas de análise utilizadas para o isolamento e caracterização de metabólitos secundários vêm sendo empregadas como métodos auxiliares rápidos e eficientes para identificação e classificação de espécies vegetais. M. salicifolia é popularmente conhecida no Brasil, como "cafezinho". O chá obtido a partir de folhas frescas é usado topicamente para aliviar pruridos e sintomas alergiformes. Este trabalho apresenta a utilização do CCD em sílica gel e espectrofotometria no UV / Vis como métodos auxiliares na identificação botânica de M. salicifolia. Os resultados demonstraram que este processo pode ser usado na diferenciação de plantas do mesmo gênero, assim como detectar variações químicas entre indivíduos de uma mesma espécie.

The great variety of angiosperms shows the need to development of botanical classification systems supported by phytochemistry, biochemistry and others. Recently, techniques of analysis used for the isolation and characterization of secondary metabolites have been employed as auxiliary quick and efficient methods for the identification and classification of plant species. M. salicifolia is popularly known in Brazil, as "small coffee" and decoct obtained from its fresh leaves is topically used to alleviate itches and other skins allergic symptoms. This work presents the use of TLC and UV/Vis spectrophotomety processes to be applied like an auxiliary method in botanical taxonomy. The results demonstrate that this process can be used in differentiation of the same genera species, and in the selection of chemical variations between individuals of the same species.