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- Laccase bioconjugate and multi-walled carbon nanotubes-based biosensor for bisphenol A analysisPublication . Bravo, Iria; Prata, Mariana; Torrinha, Álvaro; Delerue-Matos, Cristina; Lorenzo, Encarnación; Morais, SimoneBisphenol A (BPA) is an endocrine disruptor compound that has been detected in aquatic ecosystems. In this work, the development of an electrochemical biosensor for BPA determination based on laccase from Trametes versicolor is reported. A bioconjugate was optimized to maximize the biosensor electrocatalytic activity and stability, which for the first time involved the synergistic effect of this specific enzyme (6.8 UmL−1), chitosan (5 mgmL−1) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate in an optimum 5:5:2 (v/v/v) proportion. This bioconjugate was deposited onto a screen-printed carbon electrode previously modified with multi-walled carbon nanotubes (MWCNTs). Nanostructuration with MWCNTs enlarged the electrocatalytic activity and surface area, thus improving the biosensor performance. The BPA electrochemical reaction follows an EC mechanism at the optimum pH value of 5.0. Linearity up to 12 µM, a sensitivity of (6.59 ± 0.04) × 10-2 μAμM−1 and a detection limit of 8.4 ± 0.3 nM were obtained coupled with high reproducibility (relative standard deviations lower than 6%) and stability (87% of the initial response after one month). The developed biosensor was employed to the analysis of BPA in river water displaying appropriate accuracy (94.6–97.9%) and repeatability (3.1 to 6% relative standard deviations) proving its high potential applicability for in situ environmental analysis.
- Life Cycle Assessment and Life Cycle Cost of an Innovative Carbon Paper Sensor for 17α-Ethinylestradiol and Comparison with the Classical Chromatographic MethodPublication . Martins, Florinda; Torrinha, Álvaro; Delerue-Matos, Cristina; Morais, SimoneNowadays there is a growing concern with the environment and sustainability, which means that better methods, including pollutants analysis, with less consumption of materials, organic solvents, and energy, need to be developed. Considering the almost inexistent information about the topic, the main goal of this work was to compare the environmental impacts of two analytical methods, a traditional one based on liquid chromatography with fluorescence detection and a newly developed carbon paper sensor. The selected analyte was 17α-ethinylestradiol, which is a contaminant of emergent concern in aquatic ecosystems due to its endocrine disruptor behavior. The life cycle assessment data showed that the sensor detection presents an almost negligible environmental impact when compared with the extraction step (the same for both methods) and the liquid chromatographic determination (roughly 80 times higher than with the sensor). The sensor values for all categories of damage are below 3% of the total method impacts, i.e., 1.6, 1.9, 2.4, and 2.9% for resources, climate change, human health, and ecosystem quality. The extraction represents 98.1% of the sensor environmental impacts (and 99.6% of its life cycle costing) and 38.8% of the chromatographic method. This study evidences the need of developing and applying greener analytical (detection and extraction) strategies
- Commercial octopus species from different geographical origins: Levels of polycyclic aromatic hydrocarbons and potential health risks for consumersPublication . Oliveira, Marta; Gomes, Filipa; Torrinha, Álvaro; Ramalhosa, Maria João; Delerue-Matos, Cristina; Morais, SimonePolycyclic aromatic hydrocarbons (PAHs) are persistent pollutants that have been raising global concern due to their carcinogenic and mutagenic properties. A total of 18 PAHs (16 USEPA priority compounds, benzo(j)fluoranthene and dibenzo(a,l)pyrene) were assessed in the edible tissues of raw octopus (Octopus vulgaris, Octopus maya, and Eledone cirrhosa) from six geographical origins available to Portuguese consumers. Inter- and intra-species comparison was statistically performed. The concentrations of total PAHs (∑PAHs) ranged between 8.59 and 12.8 μg/kg w.w. Octopus vulgaris caught in northwest Atlantic Ocean presented ΣPAHs significantly higher than those captured in Pacific Ocean and Mediterranean Sea, as well as than the other characterized species from western central and northeast Atlantic Ocean. PAHs with 2-3 rings were the predominant compounds (86-92% of ∑PAHs) but diagnostic ratios indicated the existence of pyrogenic sources in addition to petrogenic sources. Known and possible/probable carcinogenic compounds represented 11-21% of ΣPAHs. World and Portuguese per capita ingestion of ∑PAHs due to cephalopods consumption varied between 1.62-2.55 × 10-4 and 7.09-11.2 × 10-4 μg/kg body weight per day, respectively. Potential risks estimated for low and high consumers according to USEPA methodology suggested that a regular consumption of raw octopus does not pose public health risks.
- (Bio)Sensing Strategies Based on Ionic Liquid-Functionalized Carbon Nanocomposites for Pharmaceuticals: Towards Greener Electrochemical ToolsPublication . Torrinha, Álvaro; Oliveira, Thiago M. B. F.; Ribeiro, Francisco W. P.; de Lima-Neto, Pedro; Correia, Adriana N.; Morais, SimoneThe interaction of carbon-based nanomaterials and ionic liquids (ILs) has been thoroughly exploited for diverse electroanalytical solutions since the first report in 2003. This combination, either through covalent or non-covalent functionalization, takes advantage of the unique characteristics inherent to each material, resulting in synergistic effects that are conferred to the electrochemical (bio)sensing system. From one side, carbon nanomaterials offer miniaturization capacity with enhanced electron transfer rates at a reduced cost, whereas from the other side, ILs contribute as ecological dispersing media for the nanostructures, improving conductivity and biocompatibility. The present review focuses on the use of this interesting type of nanocomposites for the development of (bio)sensors specifically for pharmaceutical detection, with emphasis on the analytical (bio)sensing features. The literature search displayed the conjugation of more than 20 different ILs and several carbon nanomaterials (MWCNT, SWCNT, graphene, carbon nanofibers, fullerene, and carbon quantum dots, among others) that were applied for a large set (about 60) of pharmaceutical compounds. This great variability causes a straightforward comparison between sensors to be a challenging task. Undoubtedly, electrochemical sensors based on the conjugation of carbon nanomaterials with ILs can potentially be established as sustainable analytical tools and viable alternatives to more traditional methods, especially concerning in situ environmental analysis
- The simpler the better: Highly sensitive 17α-ethinylestradiol sensor based on an unmodified carbon paper transducerPublication . Torrinha, Álvaro; Carneiro, Pedro; Dias, Diana; Delerue-Matos, Cristina; Morais, SimoneThe remarkable features of a carbon fiber paper sensor (CP) were employed for detection of the estrogenic hormone 17α-ethinylestradiol (EE2), considered a contaminant of emerging concern due to its potential ecotoxicity and widespread in the aquatic ecosystems. In this work, an unpreceded CP pre-treatment study was conducted with the (Il)-hexacyanoferrate(III) ion pair, however a bare sensor without pre-treatment revealed higher efficiency on the oxidation of EE2 compared to a chemical and electrochemical pre-treated CP and a gold nanoparticles modified CP, being thus selected for EE2 determinations. The analytical conditions were thoroughly optimized in terms of electrolyte pH (pH 7), differential pulse voltammetry parameters (modulation time 0.003 s, amplitude 0.09 V, interval time 0.1 s and step potential 0.01 V), and analyte preconcentration potential (0.4 V) and time (180 s). The hormone can be determined by the CP in a wide linear range from 0.1 to 1000 nM, achieving a detection limit of 0.14 ± 0.005 nM and an outstanding sensitivity of 1636 ± 232 μA μM−1 cm−2 in the lowest linear zone (0.1–1 nM). The sensor was validated in river water and fish reaching good recoveries (91.2 ± 4.6 to 109.0 ± 7.1%), reproducibility and repeatability. Moreover, the sensor showed high selectivity to EE2 in the presence of several potential interfering compounds and frequently prescribed drugs, though it could not discriminate the similar hormone, 17β-estradiol, being the total concentration obtained in this case. CP-based sensors emerge as efficient electroanalytical tools, suggesting that modification of the surface may not always be beneficial in terms of sensitivity
- Application of Nanostructured Carbon-Based Electrochemical (Bio)Sensors for Screening of Emerging Pharmaceutical Pollutants in Waters and Aquatic Species: A ReviewPublication . Torrinha, Álvaro; Oliveira, Thiago M. B. F.; Ribeiro, Francisco W.P.; Correia, Adriana N.; Lima-Neto, Pedro; Morais, SimonePharmaceuticals, as a contaminant of emergent concern, are being released uncontrollably into the environment potentially causing hazardous effects to aquatic ecosystems and consequently to human health. In the absence of well-established monitoring programs, one can only imagine the full extent of this problem and so there is an urgent need for the development of extremely sensitive, portable, and low-cost devices to perform analysis. Carbon-based nanomaterials are the most used nanostructures in (bio)sensors construction attributed to their facile and well-characterized production methods, commercial availability, reduced cost, high chemical stability, and low toxicity. However, most importantly, their relatively good conductivity enabling appropriate electron transfer rates—as well as their high surface area yielding attachment and extraordinary loading capacity for biomolecules—have been relevant and desirable features, justifying the key role that they have been playing, and will continue to play, in electrochemical (bio)sensor development. The present review outlines the contribution of carbon nanomaterials (carbon nanotubes, graphene, fullerene, carbon nanofibers, carbon black, carbon nanopowder, biochar nanoparticles, and graphite oxide), used alone or combined with other (nano)materials, to the field of environmental (bio)sensing, and more specifically, to pharmaceutical pollutants analysis in waters and aquatic species. The main trends of this field of research are also addressed.