Parámetros analíticos en la cuantificación de cocaína en varias matrices por cromatografía de gases en el laboratorio de química forense de la Policía Judicial Chimborazo

Abstract

The analytical parameters in the quantification of cocaine by gas chromatography were carried out in the Forensic Chemistry Laboratory of the Judicial Police of Chimborazo, so that the method used by gas chromatography in the quantification of cocaine has as objective that the results are truthful and reliable serving us for its future validation of the method. At the moment of evaluating if the work interval is satisfactory, the criteria of acceptance, precision, accuracy and linearity are developed, taking into account that to evaluate the precision it is developed in terms of repeatability. It was carried out in a range of different concentrations, the linearity was done in ascending from 5 µg/mL to 30 µg/mL, with intervals of 5 µg/mL, likewise it is developed for the accuracy with intervals of 10 µg/mL to 30 µg/mL denominating them low, medium and high concentrations respectively, and the accuracy was prepared in 6 solutions at 20 µg/mL that represents a concentration of 100%. The quantification of cocaine in the analysis sample and compared with a cocaine standard gave us as results in the linearity: the correlation coefficient, r = 0.9725665, is a value very close to the unit: in the accuracy we obtained an arithmetic average of the recovery percentage of 98.88%: and in the precision in its global variation coefficient it gave as a result 1.28%, complying with the statistical parameters. In conclusion the analytical parameters, if they presented linearity, accuracy and repeatability for the quantification of cocaine (Methyl benzoylecgonine), in the study and the method performed therefore the analysis sample contains cocaine. It is recommended the implementation and validation of the method of cocaine quantification by gas chromatography in the Forensic Chemistry Laboratory of the Judicial Police of the Province of Chimborazo.