Análise de interferentes vegetais nos testes colorimétricos de identificação preliminar da maconha (Cannabis sativa L.)

Abstract

This present work aimed to investigate if the leaves of other plant species present in the urban area from the city of Itumbiara, Goias, could generate a positive response for the FB and DL colorimetric tests, as well as perform in a analytical thin layer chromatography (TLCA) to the extract of Cannabis sativa L. and the extract of the leaves from species which presented false positive result for, at least, one of the colorimetric tests in order to compare the retention factor of the same ones. The present work consisted itself of a bibliographic and experimental character study. For the experimental procedure achievement, initially fresh leaves of 10 plant species were undergone to colorimetric tests of FB and DL, then foliar material was placed in an oven at a temperature of 100º C and proceeded to the colorimetric analysis at intervals of 12 to 12 hours until the sample reaches a constant mass. Therefore, the test of chromatography in a thin analytical layer was performed on glass plates with silica 60 for the extracts of Cannabis sativa L. from fresh leaves and after constant mass. The results showed that the ethanol extracts from fresh leaves in six of ten plant species investigated showed false-positive result for the FB test, while only one species responded positively to the DL test. After drying leaf material, four of the six false-positives identified in the analysis of FB were eliminated. With the achievement of the TLCA test, all results elucidated in colorimetric tests of FB and/or DL were eliminated, since the retention factors for marijuana extract and for plant extracts showed different values. In face of the showed results, it can be affirmed that the identification of Cannabis sativa L. requires the association of more precise analytical methods, in order to eliminate false-positive results and, consequently, judicial errors.