Ángela Inmaculada López-Lorente

A next-generation sorbent phase is introduced based on recycled polystyrene microspheres sulfonated with sulfuric acid and its application to the extraction of four representative sulfonamides (i.e., sulfanilamide, sulfaguanidine, sulfadiazine, and sulfamerazine) from biological matrices. The variables related to the sulfonation process and those affecting the extraction process have been evaluated. The in-syringe miniaturized dispersive solid-phase extraction method coupled to liquid chromatography-tandem mass spectrometry provided limits of detection of 0.8 µg L^− 1 for sulfaguanidine in urine to 32 µg L^− 1 for sulfanilamide in saliva. The precision, expressed as relative standard deviation has been evaluated at four concentration levels both intra-day and inter-day, being lower than 18.3 and 14.3% at the lower limit of detection, respectively. The accuracy, calculated with spiked urine and saliva samples and expressed as relative recovery, ranged from 86.4 to 108.5%. This strategy integrates sustainable waste recovery with the development of a high-performance, low-impact adsorbent, employing recycled materials (such as syringes and frits) to create a nearly zero-waste extraction system. This combination of recycling, analytical performance, and sustainability supports the evolution of environmental analysis toward a “white circular” model, seamlessly merging Green Science with robust analytical standards. Graphical abstract

An on-site extraction device is presented consisting of scotch tape modified with concentric domains of micrometric hydrophilic-lipophilic balance (HLB) particles surrounded by a ring of nanometric magnetic ones. On the one hand, HLB microparticles are readily available at the surface of the tape, exposed to interact with the target analytes, being responsible for the extraction capacity of the sorptive phase. On the other hand, the presence of magnetic nanoparticles enables the attachment of the modified tape onto a metallic screw via a magnet, which is then coupled to a wireless drill, enabling the stirring of the microextraction device. Both are simply fixed to the cost-effective, flexible, and versatile support, i.e., scotch tape, owing to their adhesive properties. The microextraction device has been applied to the determination of six benzophenones in swimming pool water samples. The variables that may affect the extraction process have been evaluated. Under the optimum conditions and using liquid chromatography-tandem mass spectrometry as the instrumental technique, the method provided a limit of detection of 0.03 µg L⁻¹. The intra-day precision, evaluated at three different concentration levels and expressed as relative standard deviation, was lower than 10%, which also comprises the variability within single-use sorptive tapes. The accuracy, calculated with spiked samples and expressed as relative recovery, ranged from 71 to 138%. The method was applied to the analysis of swimming pool water, revealing the presence of such compounds. Graphical Abstract

Dry-cured Iberian ham is officially classified into different commercial categories according to the pig’s breed and feeding regime. These reach very different prices, thus promoting labelling fraud and causing great damage to the food sector. In this work, a method based on Raman spectroscopy was explored as a rapid in situ screening tool for Iberian ham samples. A total of 110 samples were analyzed to assess the potential of this technique to differentiate purebred, crossbred, acorn-fed and feed-fed dry-cured Iberian ham. A continuous signal probably due to sample fluorescence was obtained, which hid the Raman scattering signal. Therefore, chemometric treatment was applied in order to extract non-apparent information. High validated classification rates were obtained for feeding regime (83.3%) and breed (86.7%). In addition, an interlaboratory study was carried out to confirm the applicability of the method with 52 samples, obtaining a validated rate above 80%.

The potential of paper as a substrate for the development of sorptive phases with applicability in microextraction and sensing is reviewed.

Gold nanoparticles (AuNPs) were produced using stainless steel as a solid reductant to assist the synthesis of metal NPs, using HAuCl₄ as a precursor. This method is very easy, quick, and cost-effective, allowing the synthesis of highly stable NPs without additional capping agents. However, the reaction mechanism is still under debate. In order to contribute to the investigation of the synthesis of AuNPs using stainless steel, different experimental conditions were tested. Cl⁻ concentration, pH of the precursor solution, as well as stainless steel composition were systematically changed. The syntheses were performed recording the open circuit potential to potentiometrically explore the electrochemical properties of the system, under operando conditions. Spectroscopic and morphological characterizations were carried out along with potentiometric monitoring, aiming at correlating the synthesis parameters with the AuNPs characteristics. As a result, an overview of the process features, and of its most reasonable mechanism were obtained.