Determination of arsenic (V) in cannabis oil by adsorption on multiwall carbon nanotubes thin film using XRF technique

Abstract

Many heavy metals, such as arsenic, mercury, and lead, can be introduced into the cannabis plant—and therefore the flowers—through cultivation in contaminated soil. We report a novel and selective method for the preconcentration and determination of As(V) in cannabis oil through their adsorption on a tertiary amine, ALIQUAT 336- Multiwalled carbon nanotubes, determinations were made directly on the solid by X-Ray Fluorescence spectrometry, which reduces the number of reagents used and minimizes the sample handling. The method here in described combines the advantages of solid phase extraction with the benefits of any X-Ray Fluorescence method associated to the large areas held by the carbon nanotubes, which make them a promising solid sorbent for preconcentration procedures. A high preconcentration factor was achieved for a very low volume of sample. The enrichment factor was calculated after considering that the thin film obtained from the 5 mL solution of 1 mg L-1 of As(V) has a real thickness of 0.04 mm and a final diameter of 16.7 mm, so that the volume deposited on the pellet was 0.0088 cm3 and the preconcentration factor can be calculated to be 104.