Detectable Concentration Range Research Articles

Revealing the Viable Microbial Community of Biofilm in a Sewage Treatment System Using Propidium Monoazide Combined with Real-Time PCR and Metagenomics

Microbial community composition, function, and viability are important for biofilm-based sewage treatment technologies. Most studies of microbial communities mainly rely on the total deoxyribonucleic acid (DNA) extracted from the biofilm. However, nucleotide materials released from dead microorganisms may interfere with the analysis of viable microorganisms and their metabolic potential. In this study, we developed a protocol to assess viability as well as viable community composition and function in biofilm in a sewage treatment system using propidium monoazide (PMA) coupled with real-time quantitative polymerase chain reaction (qPCR) and metagenomic technology. The optimal removal of PMA from non-viable cells was achieved by a PMA concentration of 4 μM, incubation in darkness for 5 min, and exposure for 5 min. Simultaneously, the detection limit can reach a viable bacteria proportion of 1%, within the detection concentration range of 102–108 CFU/mL (colony forming unit/mL), showing its effectiveness in removing interference from dead cells. Under the optimal conditions, the result of PMA–metagenomic sequencing revealed that 6.72% to 8.18% of non-viable microorganisms were influenced and the composition and relative abundance of the dominant genera were changed. Overall, this study established a fast, sensitive, and highly specific biofilm viability detection method, which could provide technical support for accurately deciphering the structural composition and function of viable microbial communities in sewage treatment biofilms.

Isolation and chemical immobilization of E. coli‐specific bacteriophage with NH2‐MIL‐101(Fe) MOF, a high photoluminescence rod‐shaped microcrystals for low‐level bacteria detection

As concern raised by the World Health Organization (WHO) of antibiotic‐resistant and bio‐defensive bacteria, a metal–organic framework (MOF) based optical biosensor came into consideration for precise, quick, and sensitive detection of Escherichia coli (E. coli) (ATCC 10799) using bacteriophage as a bio‐recognition element. In the present study, amine‐functionalized Fe‐based MOF, i.e., NH2‐MIL‐101(Fe), was synthesized by the solvothermal method (approx. 531–1106 nm in size and 20 mV zeta potentials by DLS) and further characterized by SEM, XRD, ATR‐FTIR, UV–VIS, and photoluminescent (PL) spectroscopy. The lytic bacteriophage was isolated from a sewage sample, purified, and concentrated using the ultra‐centrifugation method and achieved a high titer of 7.3 × 1012 PFU/ml. The concentration, stability, and accessible receptor binding domains (RBDs) of the biorecognition element for binding with their analytes play an important role in developing sensitive and specific biosensor systems. To fulfill the mentioned criteria, optimized glutaraldehyde concentration was estimated at 0.25%, at 30 °C for conjugating maximum bacteriophage titer of 8.6 × 105 PFU/ml for each 1 mg amine functionalized iron‐based MOF. The synthesized detection probe has shown excellent photoluminescence and antibacterial activity and achieved a detection limit of 652 CFU/ml over a bacterial detection concentration range from 5.78 × 101 to 5.78 × 106 CFU/ml for E. coli with 10–12 min of response time, high specificity, and long‐term stability even at room temperature. Therefore, it can be inferred that this MOF‐based strategy can be helpful in the specific and sensitive detection of various bacterial pathogens using bacteriophage as a bio‐recognition element.

Pesticide contamination pattern of surface water in an urban–agricultural mediterranean watershed (Wadi Guenniche, Bizerte Lagoon, Northern Tunisia)

Two years of monthly sampling and hydrological monitoring were performed at the outlet of a Mediterranean watershed in northern Tunisia to determine the contents of 469 pesticide active ingredients and metabolites in water and evaluate their behavior. Wadi Guenniche is a tributary of the Bizerte coastal lagoon, with a watershed area of 86 km2, which exhibits pluvial cereal, legume, and orchid cultivation and irrigated market gardening. Twenty-nine pesticide active ingredients and 2 metabolites were detected in water. Twenty-four pesticide active ingredients were authorized for use in Tunisia. Among them, 14 had never been mentioned in previous farmer surveys. Five herbicides and their metabolites were the most frequently detected: aminomethylphosphonic acid (AMPA) (100%), glyphosate (94%), simazine (94%), 2,4-D (70%), and deisopropylatrazine (DIA) (47%). The detection frequency and concentration range suggested that the phytosanitary pressure and resulting water contamination are close to those on the northern Mediterranean shore. These results, in addition to characterizing the pollution state, emphasized the need for additional studies on the use and fate of pesticides on the southern shore of the Mediterranean Sea, particularly in Tunisia.

Electrochemical chiral sensor developed using nanofibrous polyaniline chiral Structures: Detection and differentiation of D- and L-tryptophan

In this work, a simple strategy for electrochemical detection and differentiation of D- and L- forms of tryptophan is demonstrated using nanofibrous structures of chiral polyaniline (CP). Basically, CP with desired chirality is prepared using a chiral acid namely, ± camphor sulfonic acid (±CSA) in presence of either a cationic (or) anionic surfactant (CTAB / SDS) through a simple oxidative polymerization process. Structure, morphology and phase purity of the resultant CP materials are characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray diffraction studies. Moreover, the chiral properties of these conducting polymers are evaluated using circular dichroism (CD) spectroscopic studies. From these analyses it is found that CP exhibited twisted nanofibrous morphology and possesses the chirality whereas the non-chiral polyaniline (PANI), prepared in the absence of chiral acid, displayed the formation of a simple fibrous structures without any twists or chirality. Interestingly, such CP materials are found to be electrochemically selective for the detection and differentiation of D- and L- forms of tryptophan (Trp). Among the different chiral materials, CP-CT(−) prepared using CTAB displayed a much better sensing characteristics with higher IL/ID ratio, wider concentration range of detection and lower detection limit of 0.98 µM for l-Trp and 1.2 µM for d-Trp respectively. On the other hand, non-chiral PANI does not display any sensing behavior towards the differentiation of amino acid, Trp. Further, chronoamperometric studies reveal the selectivity of this chiral sensor for the detection of Trp among the other potentially interfering analytes. Although the difference in the measured peak current value is smaller, a significant difference of 70 mV peak potential is observed for the differentiation of L- and d-Trp. Moreover, the proposed CP-based sensing platform exhibits excellent stability and reproducibility with statistically negligible error values suggesting the potential use of the developed material towards electrochemical chiral detection and differentiation of amino acid, Trp.

Ratiometric luminescent simultaneous sensing of aristolochic acids (I-IV) by a novel metal-organic framework and its nanowire.

Aristolochic acids(AAs), which are a group of nitrophenanthrene carboxylic acids formed by Aristolochia plant, have become an increasing serious threat to humans due to their nephrotoxicity and carcinogenicity. Fast and accurate approaches capable of simultaneous sensing of aristolochic acids (I-IV) are vital to avoid intake of such compounds. In this research, the novel ratiometric fluorescence zinc metal-organic framework and its nanowire have been prepared. The two different coordination modes (tetrahedral configuration and twisted triangular bipyramidal configuration) within zinc metal-organic framework lead to the significant double emissions. The ratiometric fluorescence approach based on nanowire provides a broader concentration range (3.00 × 10-7~1.00 × 10-4 M) and lower limit of detection (3.70 × 10-8 M) than that based on zinc metal-organic framework (1.00 × 10-6~1.00 × 10-4 M, 5.91 × 10-7 M). The RSDs of the results are in the range 1.4-3.5% (nanowire). The density functional theory calculations and UV-Vis absorption verify that the sensing mechanism is due to charge transfer and energy transfer. Excellent spiked recoveries for AAs(I-IV) in soil and water support that nanowire is competent to simultaneously detect these targets in real samples, and the proposed approach has potential as a fluorescence sensing platform for the simultaneous detection of AAs (I-IV) in complex systems.

A Low-cost Two-in-one Fluorescence/ Colorimetry Ammonium Detector: Design and Application

In this study, a compact and low-cost ammonium detector integrated spectrophotometric and fluorescence detection was designed based on the reaction of ammonium and o-phthalaldehyde in the presence of sodium sulfite solution to form substances with both photometric properties and fluorescence. This two-in-one detector detects ammonium in spectrophotometric mode at high concentrations and in fluorescence mode at low concentrations. The detector with a total size of 5×5×5 cm2 and integrates the detector skeleton box, light source, attenuator, filter, photoelectric sensor, data acquisition card, constant current source circuit, and LabVIEW upper computer acquisition program. Also, the detector was applied to the determination of water samples with a wide range of ammonium concentrations, showing good performance. The detector has the advantages of low cost, miniaturization, easy operation, and wide detection concentration range. This two-in-one detector has good potential for ammonium detection in the field, especially where ammonium concentration varies widely.

Laser-induced graphene decorated with Ni[sbnd]Pt alloy nanoparticles for non-enzymatic electrochemical quantification of glucose

Enzyme-free electrochemical glucose (Glu) sensors, adopting electrochemically active catalysts, are of vital significance to effectively monitoring and analyzing the blood Glu level in diabetes diagnosis. Meanwhile, developing novel electrode substrates have been the hot research pot to meet the demand for constructing flexible sensors. In this work, porous laser-induced graphene (LIG) was prepared through a facile one-step laser-engraving technique on a polyimide thin film, and then used directly as the electrode. Furthermore, NiPt alloyed nanoparticles (NPs) were electrodeposited on the LIG electrode surface to gain the NiPt/LIG composite electrode, which was applied to construct the nonenzymatic electrochemical Glu sensor. The morphology, element and electrochemical performance of NiPt/LIG composite was characterized through various techniques. NiPt alloyed NPs were homogeneously distributed on the LIG scaffolds, which possess plenty of porous structure, high surface area and many active sites. The cooperative effect between the outstanding electrocatalytic capacity of NiPt alloyed NPs, the extraordinary electroconductibility of LIG and the numerous exposed active sites endow the NiPt/LIG sensor outstanding electrocatalytic performance for electrochemical oxidation of Glu. Under the most appropriate conditions, the obtained NiPt/LIG sensor was adopted to detect Glu, showing a broad detection concentration range of 0.5 μM to 2.1 mM and 2.1 mM to 5.6 mM, good sensitivities of 1.824 and 0.467 μA μM−1 cm−2, a low detection limit of 0.03 μM. The as-fabricated nonenzymatic Glu sensor also displays high selectivity, stability considering ageing effects under different environment conditions and prominent reproducibility. Additionally, this novel NiPt/LIG nonenzymatic Glu sensor was applied to quantify Glu successfully in blood serum and food samples and the results were in good agreement with that by UV–vis spectrophotometer, demonstrating high precision and accuracy as well as excellent recovery, showing good application prospects in Glu monitoring. This research confirmed the potential of exploiting NiPt/LIG as a highly sensitive Glu nonenzymatic electrochemical sensor and provided a practicable and suitable approach for construction of novel electrochemical sensors.

Non-enzymatic sensor based on doped polyindole/multi-walled carbon nanotube for detecting neurotransmitter acetylcholine

A facile non-enzymatic acetylcholine sensor composed of doped-polyindole/multi-walled carbon nanotube (dPIn-MWCNT) composite was designed, fabricated, and presented here. The negative current response toward acetylcholine concentration was first found and reported here. The confirmation of acetylcholine detection mechanism was elucidated by XPS, where the acetylcholine interaction resulted in a decrease in the % (dPIn doping level and an increase of the dPIn structural defect. The response optimizations with dPIn concentrations, applied potentials, and incubation times were systematically investigated. The 45dPIn-15MWCNT operated at + 0.6 V vs. Ag/AgCl with 5 min of incubation time was the optimum condition to obtain the highest acetylcholine current response. Chronoamperometric acetylcholine detection revealed two distinct current regimes from the acetylcholine surface interaction and the de-doping of dPIn. Regime I was related to the diffusion-controlled process as observed in the low concentration range of 10−8–10−5 M. Regime II corresponded to the mixed diffusion-controlled and adsorption-controlled process as observed in the concentration range of 10−5–10−2 M. For regime I, the calculated LOD was as low as 1.27 nM with a very high acetylcholine response sensitivity. Regime I is suggested for the point-of-care utility, where the detectable concentration range covered the acetylcholine level normally found in the healthy human blood. Regime II can be applicable and useful in the treatment monitoring of neurological diseases.

A self-powered and supercapacitive microneedle continuous glucose monitoring system with a wide range of glucose detection capabilities

Continuous detection of sudden changes in blood glucose is essential for individuals with diabetes who have difficulty in maintaining optimal control of their blood glucose levels. Hypoglycemic shock or a hyperglycemic crisis are likely to occurs in patients with diabetes and poses a significant threat to their lives. Currently, commercial continuous glucose monitoring (CGM) has limits in the glucose concentration detection range, which is 40–500 mg/dL, making it difficult to prevent the risk of hyperglycemic shock. In addition, current CGMs are invasive, cause pain and irritation during usage, and expensive. In this research, we overcome these limitations by introducing a novel mechanism to detect glucose concentration using supercapacitors. The developed CGM, which is self-powered and minimally invasive due to the use of microneedles, can detect a wider range of glucose concentrations than commercial sensors. In addition, efficacy and stability were proven through in vitro and in vivo experiments. Thus, this self-powered, microneedle and supercapacitive-type CGM can potentially prevent both hypoglycemic and complications of hyperglycemia without pain and with less power consumption than current commercial sensors.

Quantitative analysis of microplastics in water environments based on Raman spectroscopy and convolutional neural network

With the increasing interest in microplastics (MPs) pollutants, quantitative analysis of MPs in water environment is an important issue. Vibrational spectroscopy, represented by Raman spectroscopy, is widely used in MP detection because they can provide unique fingerprint characteristics of chemical components of MPs, but it is difficult to provide quantitative information. In this paper, an ingenious method for quantitative analysis of MPs in water environment by combining Raman spectroscopy and convolutional neural network (CNN) is proposed. It is innovatively proposed to collect the average mapping spectra (AMS) of the samples to improve the uniformity of Raman spectroscopy detection, and to increase the effective detection range of concentration by filtering different volumes of the same MP solutions. In order to verify the universality and effectiveness of the proposed method, 6 different sizes of Polyethylene (PE) MPs were used as detection objects and mixed into 5 different actual water environments. The R2 and RMSE of CNN for identifying the concentration of PE solutions could reach 0.9972 and 0.033, respectively. Meanwhile, by comparing machine learning models such as Random Forest (RF) and Support Vector Machine (SVM) were compared, and CNN combined with Raman spectroscopy has significant advantages in identifying the concentration of MPs.

Tuning the fluorescence emission of water-stable CsPb(Br/I)3 perovskite nanocrystal probes for naked-eye visual detection of mercury ion

All-inorganic cesium lead halide perovskite nanocrystals (PNCs) have rarely been reported in analytical chemistry, especially in water environment analysis, due to their high susceptibility to environmental conditions. Herein, we investigate and report a method of visual detection of Hg2+ concentration in aqueous solution using CsPb(Br/I)3 PNCs. In this strategy, three kinds of CsPb(Br/I)3 PNCs with FL emission peaks of 551 nm, 591 nm, and 617 nm were used to detect Hg2+, and it was found that Hg2+ can quench the fluorescence of CsPb(Br/I)3 PNCs and blue-shift the maximum FL emission peak. We also found that the Hg2+ concentration has a good linear relationship with the fluorescence quenching rate (I0/I) and FL emission peak shift (Δλ) of CsPb(Br/I)3 PNCs. With the red-shift of the probe FL emission peak, the detected concentration range of Hg2+ gradually expanded. Therefore, the possibility of detecting Hg2+ concentration without huge equipment was detailed by examining the red (R), green (G), and blue (B) values of photographs of CsPb(Br/I)3 PNCs with Hg2+. Under a 365 nm ultraviolet (UV) lamp, the solution color of CsPb(Br/I)3 PNCs emission peaks at 591 nm gradually changes from orange to green with the increase of Hg2+ concentration, which has an excellent visualization effect. The method presented here has the potential to establish a new analytical method for the visual detection of Hg2+ in aqueous environments, and may also facilitate the application of all-inorganic cesium lead halide perovskite nanocrystals for analytical detection in aqueous environments.

Synthesis of (3‐Thienyl)‐Substituted 2,2’‐Bipyridines and Their Application as Activators of Platinum Electrode Catalytic Activity Towards Cholesterol Electrooxidation

AbstractSeveral new derivatives of 2,2′‐bipyridines with a spacer group separated from the 2,2‐bipyridine fragment, namely, an ethynyl fragment, were obtained using the Sonagashira cross‐coupling reaction. The resulting derivatives were physically adsorbed on platinum electrode and were then used as activators of the catalytic activity of a platinum electrode in the reaction of cholesterol electrooxidation in an acetonitrile medium. Sensitivity, limit of detection and detectable concentration range were calculated, and the best results was established as 6.2±0.6 μA/mM, 0.08 mM and 0–0.3 mM, respectively. These results show that the prepared compounds adsorbed on platinum electrode are perspective systems for developing of new enzymeless cholesterol sensor based on them.

Ultrathin Langmuir-Blodgett film of functionalized single-walled carbon nanotubes for enhanced acetone sensing

Acetone is one of the important volatile organic compounds which needs to be detected from the industrial effluent and as a bio-marker from breath of diabetic patients. Here, ultrathin Langmuir-Blodgett (LB) film of octadecylamine- functionalized single-walled carbon nanotubes (ODA-CNT) was formed on interdigitated gold electrodes and was employed for acetone vapor sensing using the impedance spectroscopy (IS) at room temperature. The LB film deposited in liquid-like phase of the Langmuir monolayer of ODA-CNT revealed aligned nanotubes. Being a reducing agent, acetone interacts readily with the CNTs through the transfer of electrons. Using IS, multiparameter were measured with respect to both frequency and acetone vapor concentration. Principal component analysis (PCA) of the IS data revealed capacitance as the most suitable parameter for acetone vapor sensing using the ODA-CNT film. A very low limit of detection (0.5 ppm) and a wide detectable concentration range (1–300 ppm) for acetone sensing using the LB film of ODA-CNT was obtained. The 2D calibration map revealed that the sensing performance of acetone using LB film was much better as compared to that of drop-cast film of ODA-CNT and LB film of pristine CNTs. The superior sensing performance of the LB film of ODA-CNT is attributed to the uniform and aligned nature of the nanotubes, leading to a coherent behavior due to interaction with the acetone molecules. This study shows the potential of LB films of ODA-CNT for sensitive and low level detection of acetone vapor at room temperature.

Selective determination of an ovarian cancer biomarker at low concentrations with surface imprinted nanotube based chemosensor

In this study, an electrochemical chemosensor that utilizes a conductive polymer-based molecularly imprinted polymer (MIP) surface for rapid and reliable determination of CA125 was devised. A novel method has been applied to fabricate CA125 imprinted polypyrrole nanotubes (MI-PPy NT) via vapor deposition polymerization (VDP) as a recognition element for highly selective and sensitive determination of CA125. The chemosensor was prepared by immobilizing MI-PPy NT onto screen-printed gold electrodes (Au-SPE) and the performance of the sensor was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in terms of selectivity, sensitivity, linear dynamic concentration range (LDR) and limit of detection (LOD). The MI-PPy NT@Au-SPE sensor exhibited high sensitivity (68.57 μA per decade) to the CA125 concentration ranging from 0.1 U mL−1 to 100 U mL−1 at an LOD of 0.4 U mL−1 with a correlation coefficient of 0.9922. The developed chemosensors with their novel design combined with a facile fabrication method, prove to be promising as future state-of-the-art biosensors.

Enhanced ammonia sensing performance of barium hexaferrite enabled through Zn doping: Mechanistic study considering modulation of Fe2+/Fe3+ ratio and oxygen vacancy

Barium hexaferrite (BaFe12O19) is an unexplored metal-oxide semiconductor with regard to ammonia (NH3) gas sensing. Herein, we have achieved substantial enhancement in response towards NH3 by virtue of Zn doping in BaFe12O19, synthesized via facile solid-state route. The improved response (Rgas/Rair) of Zn-doped BaFe12O19 towards 1 ppm NH3 was 7.36 at 250 °C which was ∼300% higher than pure BaFe12O19. Moreover, fast response/recovery time (2.66 s/35.25 s), good selectivity and long-term stability (100 days) towards NH3 has been achieved when Zn was incorporated. The lower limit of detection of Zn doped BaFe12O19 was estimated ∼150 ppb, that exceedingly favors lower concentration range of NH3 detection. Excellent sensing behavior of Zn-doped BaFe12O19 samples was attributed to modulation of Fe2+/Fe3+ ratio, oxygen vacancies and improved oxygen adsorbing ability as confirmed from X-ray photoelectron spectroscopy (XPS) study. Also, the improvement in sensing activity was validated through quenching of photoluminescence (PL) spectra in favor of electron-hole separation. The usefulness of developed Zn-doped BaFe12O19-based sensor for environmental air-quality surveillance and individualized health monitoring can be concluded through the sensor's notable resolution in detection of wide range (150 ppb - 100 ppm) of ammonia concentration.

Construction of test strips for lung cancer detection based on aptamers

Lung cancer is the most common malignancy worldwide. Early diagnosis helps to reduce mortality and improve survival. Aptamers are widely used in cancer screening because of their high specificity, good stability and low cost. In this study, using the specific aptamer of lung cancer serum, the sandwich method colloidal gold test strip was prepared by isothermal amplification technique and the principle of nucleic acid hybridisation for the early diagnosis of lung cancer. The results showed that the test strip was positive in 8 patients with lung cancer, which was consistent with the actual cases. The test strip can accurately identify lung cancer patients. The concentration range of nucleic acid detection is 1 × 10−4 - 7 × 10−4 mol/L, and the detection limit is 0.67 mM. The test strip detection method has low cost and simple operation, and provides a reference for the development of home portable tumor early detection.

A lipase-conjugated carbon nanotube fiber-optic SPR sensor for sensitive and specific detection of tributyrin.

As a low-density lipoprotein, tributyrin plays an essential role in food safety and human health. In this study, a novel lipase-conjugated carbon nanotube (CNT) surface plasmon resonance (SPR) fiber-optic sensor is used to specifically detect tributyrin for the first time. In this work, CNTs can be used as an amplifying material to significantly increase the sensitivity of SPR sensors due to their high refractive index and large surface area. CNTs can also be used as an enzyme carrier to provide abundant carboxyl groups for the specific binding of lipases. Covering the surface of the sensor with CNTs can not only enhance the performance of the sensor, but also provide sufficient detection sites for subsequent biomass detection, reduce the functionalization steps, and simplify the sensor preparation process. The experimental results demonstrate that the refractive index sensitivity of the traditional multimode fiber (MMF)-single mode fiber (SMF)-MMF transmissive optical fiber sensor is 1705 nm RIU-1. After covering the sensor with CNTs, the sensitivity is 2077 nm RIU-1, and the sensitivity has been improved very well. In addition, there are abundant functional groups on CNTs, which can provide abundant binding sites. Conjugating lipase on carbon nanotubes helps to achieve linear detection in the range of 0.5 mM to 4 mM tributyrin, with a sensitivity of 4.45 nm mM-1 and a detection limit of 0.34 mM, which is below the 2.26 mM detection standard and meets food safety monitoring requirements. Compared with other sensors, the optical fiber biosensor proposed in this study expands the concentration detection range of tributyrin. Furthermore, the sensor also has good stability, anti-interference performance and specificity. Therefore, the sensor proposed in this paper has good application prospects in the fields of food safety and biomedicine.

Facile Synthesis of Platinum Nanoparticle-Embedded Reduced Graphene Oxide for the Detection of Carbendazim.

In recent years, there has been a significant interest in the advancement of electrochemical sensing platforms to detect pesticides with high sensitivity and selectivity. Current research presents a novel approach utilising platinum nanoparticles (NPs) and reduced graphene oxide deposited on a glassy carbon electrode (Pt-rGO/GCE) for direct electrochemical measurement of carbendazim (CBZ). A straightforward one-step electrodeposition process was applied to prepare the Pt-rGO sensing platform. The incorporation of conductive rGO nanosheets along with distinctive structured Pt NPs significantly enhanced the effective electrode surface area and electron transfer of CBZ. Additionally, when exposed to 50 µM CBZ, Pt-rGO/GCE exhibited a higher current response compared to the bare electrode. Further investigations were performed to analyse and optimise the experimental parameters that could influence pesticide detection. Under the optimised conditions of pH 7 and 5 min of accumulation time, the Pt-rGO/GCE sensor showed a linear concentration detection range from 0.1 µM to 50 µM, with a detection limit of 3.46 nM. The fabricated sensor was successfully employed for CBZ detection in milk and tap water with 98.88% and 98.57% recovery, respectively. The fabricated sensor showed higher sensitivity and reproducibility, thus indicating the potential of this technology in the development of reliable sensors for the detection of CBZ or similar pesticides in forthcoming applications.

The Influence of the Nature of the Polymer Incorporating the Same A3B Multifunctional Porphyrin on the Optical or Electrical Capacity to Recognize Procaine.

The multifunctionality of an A3B mixed-substituted porphyrin, namely 5-(4-carboxyphenyl)-10,15,20-tris(4-methylphenyl)porphyrin (5-COOH-3MPP), was proven due to its capacity to detect procaine by different methods, depending on the polymer matrix in which it is incorporated. The hybrid nanomaterial containing k-carrageenan and AuNPs (5-COOH-3MPP-k-carrageenan-AuNPs) was able to optically detect procaine in the concentration range from 5.76 × 10-6 M to 2.75 × 10-7 M, with a limit of detection (LOD) of 1.33 × 10-7 M. This method for the detection of procaine gave complementary results to the potentiometric one, which uses 5-COOH-3MPP as an electroactive material incorporated in a polyvinylchloride (PVC) membrane plasticized with o-NPOE. The detected concentration range by this ion-selective membrane electrode is wider (enlarged in the field of higher concentrations from 10-2 to 10-6 M), linearly dependent with a 53.88 mV/decade slope, possesses a detection limit of 7 × 10-7 M, a response time of 60 s, and has a certified stability for a working period of six weeks.

Associated factors with mycotoxin exposure in Spanish population

Human exposure to mycotoxins is a global concern since filamentous fungi can contaminate food and feed from crops to ready-to-eat meals. Human urine biomonitoring is a widely used technique to evaluate mycotoxins exposure, as an alternative to food correlation studies. The aim of this study is to describe human exposure to mycotoxins and to investigate the associated sociodemographic, lifestyle and dietary variables. Participants were 540 women from the Valencia (Spain) cohort of the Spanish Childhood and Environment Project (INMA). A validated multi-mycotoxin method using HPLC-Q-TOF-MS was applied to determine the concentration of ten selected mycotoxins: Enniatin A, Enniatin B, Enniatin A1, Enniatin B1, Beauvericine, Aflatoxin B1, Aflatoxin B2, Aflatoxin G1, Aflatoxin G2 and Ochratoxin A. A simultaneous untargeted screening of mycotoxins and their metabolites has been performed. Mycotoxins associations were assessed by bivariate and multivariate regression models using participants' sociodemographic, lifestyle and dietary data collected through questionnaires. Mycotoxins were detected in 81% of urine samples. The method quantified mycotoxins concentrations in up to 151 samples. Most quantified mycotoxins were: Enniatin B [% of detection (concentration range)] = 26% (1.0–39.7 ng/mg) and Enniatin B1 = 7% (0.5–14.4 ng/mg). Besides the ten-targeted mycotoxins, other mycotoxins and metabolites were studied, and higher incidence was observed for Deepoxy-deoxynivalenol (45%), Ochratoxin B (18%) and Ochratoxin α (17%). Higher mycotoxins concentrations were associated with rural areas as well as with participants belonged to lower social class, beer, light sodas and fruit juice consumers. On the contrary, higher processed meat intake was related to lower mycotoxins’ levels. Studies are required to better evaluate the exposure to mycotoxins from food and their environmental relationships.