to SPME and LPME. In relation to LPME, no loss of liquid film takes place with thin films, and compared with SPME, the greater surface area of the film avoids saturation problems. The TFME process is based on direct contact of the film with a sample for the extraction of the analytes, and subsequently, the elution of the analytes entrapped in the film using a small volume of the appropriate solvent. Various sampling formats were studied for the TFME technique. In the simplest approach, the film is placed in the sample matrix without being held in position or coated on the surface of the sample vial [5]. Alternatively, TFME keeps the film in a fixed position using a stainless-steel rod as the support, which is attached to the cap of the vial by piercing through the septum or a Teflon holder. Among the polymers, polydimethylsiloxane (PDMS) has been mainly used for this purpose [5], as well as ethylene-vinyl acetate in vial-coated TF-SPME and mixed-phase thin films of polydimethylsiloxane/divinylbenzene (PDMS/DVB) or carboxen/polydimethylsiloxane (CAR/DVB) prepared on glass wool substrates [5]. Mixed sorptive phases have been synthesized and provide balanced coverage of analytes with a broad range of chemical properties [8]. Both our group and others have previously reported the use of functionalised polymer inclusion membranes (PIMs) for the separation and preconcentration of inorganic species and antibiotics [9; 10; 11; 12; 13]. PIM preparation is simple, with the appropriate amount of the polymer and a plasticizer mixed in a desired proportion, and can be functionalised by adding extractants, typically used in liquid-liquid extraction, that act as carriers by interacting with the compound of interest. PIM stability has recently been evaluated by the addition of inorganic nanoparticles or carbon nanotubes (CNTs), which have been applied in the enrichment of arsenate and phosphate [14]. Moreover, PIMs containing a polymer and a plasticizer have been successfully used by our group in the preconcentration of organic pollutants [15; 16], where the plasticizer not only provides flexibility to the film but also affords an adequate organic phase for the extraction. The application of these polymeric films was tested for the determination of pesticides (chlorpyrifos, cyprodinil, and diazinon) [15], and emerging pollutants tricolson (TCS) and tonalide (AHTN) [15]. Under exhaustive extraction conditions (contact time of six hours), absolute recoveries for pesticides of between 45-70% were obtained for the PIM-assisted extraction method and between 75-110% for AHTN and TCS. However, the leaching of the plasticizer in the aqueous solution was noticed [16], which affected the chromatographic analysis. Given this, alternative modifiers are also under investigation to improve the greenness of the methodology. Nanomaterials, which have sizes ranging from 1 to 100 nm in one or more dimensions, are at the core of innovation in many technological areas as well as in analytical chemistry [17]. Multi-walled carbon nanotubes (MWCNTs) are composed of single-wall carbon nanotubes with additional graphene tubes around their core. The highly developed hydrophobic surface of CNTs exhibits strong sorption properties toward various compounds, and CNTs have shown great potential in adsorbing toxic ions and organic contaminants from domestic and industrial wastewater [18; 19; 20]. Within analytical chemistry, MWCNTs and other derived carbon materials have been used for the preconcentration of trace amounts of organic compounds from environmental samples [21; 22; 23; 24; 25; 26; 27] and in D-\(\mu\)-SPE [28; 29]. Their application in TFME is not so ubiquitous. One approach, called simultaneous liquid-liquid microextraction and CNT-reinforced hollow-fibre microporous membrane solid-liquid phase microextraction, uses a hollow-fibre porous membrane impregnated with a CNT dispersion and has been tested in the extraction of organophosphorus compounds (OP) from watermelon samples [30] and non-steroidal anti-inflammatory drugs from urine samples [31].