Novel Method for the Extraction of Cocaine from Oral Fluid by Means of Disposable Pipette Modified with Restricted Access Material

This study proposes a new, efficient, and selective method for the analysis of cocaine in oral fluid. For this purpose, an extractive phase with restricted access materials (RAM) capable of extract and pre-concentrate low molecular weight analytes and simultaneously exclude macromolecules was developed for disposable pipette extraction (DPX) followed by liquid chromatography coupled to mass spectrometry (LC-MS) analyses. The proposed method was optimized using a 24 factorial design which pointed higher extraction efficiency under the following conditions: pH 9, 10 cycles of extraction (aspirate/dispense), 3 cycles of desorption (aspirate/dispense) and acetonitrile as desorption solvent. The DPX-RAM/LC-MS method showed linearity range from 10 to 100 ng mL-1 with determination coefficient (R2) = 0.999, accuracy values ranged from -0.9 to 4.3%, precision values ranged from 1.7 to 9.1% and recovery values ranged from 97.9 to 101.1%. The benefits of this method are that it can be performed in few minutes and that the analytical performances, including the limit of detection (3.13 ng mL-1), limit of quantitation (10 ng mL-1) and linear range were found to be in agreement with other methods used for similar analysis.

Temperature and magnetic dual responsive restricted access material for the extraction of malachite green from crucian and shrimp samples

A restricted access material that does not need organic solvents during elution was prepared for the extraction of malachite green.