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This manuscript describes the development of magnetic restricted-access carbon nanotubes (M-RACNTs) for use as SPME sorbent to determine cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) in human plasma samples by UHPLC-MS/MS. The adsorptive phase was immobilized on an SPME device by electromagnetic interactions between the M-RACNTs and a cylindrical neodymium magnet (3-mm diameter x 8-mm height) attached to a stainless-steel rod (3-mm diameter x 40-mm height). The M-RACNTs were synthesized by incorporating Fe

Analytical chemistry has always been evolving towards techniques that are increasingly simple and effective and that conform to green principles. Disposable pipette extraction (DPX, also known as dispersive pipette tip solid phase extraction) is a recent technique that has become an interesting tool in sample preparation methodologies. The principle is based on a dynamic mixture between the matrix and the sorbent which allows rapid and effective extraction of analytes and provides vigorous clean-up of the samples. In the context of fitting in with green chemistry, DPX has contributed to replacing commercially available materials with natural alternative materials. The production of these materials is also simple, reduces sample/solvent volumes, consequently generates less waste and is less laborious and safer for the laboratory worker. This review is a source of information about the DPX technique, dealing with its basic concepts, procedure, optimizations, materials for the main applications published so far, which are in the food, environmental and biological (forensic) sciences.

In this paper, a remodeling of the bar adsorptive microextraction (BAμE) technique is proposed with impregnation of the derivatization reagent on the surface of the adsorptive bar containing a biosorbent material. The derivatization reagent was 2,4-dinitrophenylhydrazine (DNPH), which was adsorbed on the surface of the bar containing cork powder as the extractor phase for the determination of two aldehydes (hexanal and heptanal) which are known as lung cancer biomarkers in human urine samples. The derivatization reaction and the extraction occurred simultaneously on the surface of the bar (length 7.5 mm) under acidic conditions. The method optimization was carried out by univariate and multivariate analysis. The optimal conditions for the method were a DNPH to aldehydes ratio of 40:1, buffer solution of pH 4.0, extraction time of 60 min and liquid desorption of 10 min in 100 μL of acetonitrile. The aldehydes were analyzed by HPLC-DAD with a simple and fast (6 min) chromatographic run. The limits of detection (LODs) for hexanal and heptanal were 1.00 and 0.73 μmol L−1, respectively. The relative recoveries in urine samples ranged from 88 to 111% with relative standard deviations (RSDs) being less than 7%. The method developed is of low cost and can be successfully used for the quantification of these two lung cancer biomarkers in human urine samples, potentially providing an early diagnosis of lung cancer.