Comparing determination methods of detection and quantification limits for aflatoxin analysis in hazelnut

Exposure And Health Risk Assessment Of Aflatoxins In Hot Red Pepper Marketed In North Shewa Zone, Oromia Region, Ethiopia

Aflatoxins (AFs) are secondary metabolites mainly produced by Aspergillus flavus and A. parasiticus and their contamination of red peppers can cause hepatocellular carcinoma, growth retardation in children, immune suppression, and death. In addition, their presence in the red peppers can affect international trade and cause significant economic burdens. Thus, the objective of this study was to assess the level of AFs contamination in packed powder (from supermarkets) and raw red pepper samples commercially available in the towns of Fiche and Mukaturi. Furthermore, this study aimed to determine the potential health and cancer risks associated with the consumption of red pepper contaminated with AFs. Red pepper samples (raw and packed powder) were collected randomly from the Fiche and Mukaturi open markets. Then AFs in the samples were extracted using methanol: water (80:20, v/v). These extract samples were then cleaned up using an immunoaffinity column (IAC) and determined with a high-performance liquid chromatography-fluorescence detector (HPLC-FLD). The finding showed that the amount of AFB1, AFB2, and AFG1 in raw red pepper was found to be 3.19 ± 0.01, 0.19 ± 0.001, and 4.07 ± 0.01 μg kg-1, respectively. The raw red pepper samples had a total of 7.66 ± 0.01 μg kg-1 of AFs. On the other hand, the amount of AFB1, AFB2, and AFG1 in Afiya-packed red pepper was found to be 7.04 ± 0.03, 2.15 ± 0.06, and 0.50 ± 0.01 μg kg-1, while Mudayi packed red pepper contained 31.60 ± 0.22, 24.40 ± 0.17, 3.37 ± 0.02 and 2.48 ± 0.004 μg kg-1 of aflatoxins, respectively. Afiya and Mudayi packed powder peppers had a total AFs content of 10.4 ± 0.07 and 61.90 ± 0.28 μg kg-1, respectively. The total AFs concentrations in packed pepper powder samples were higher than maximum toleratable limits (MTLs) set by the European Commission Regulation (EU) 2023/915 (5.00 μg kg-1 for AFB1 and 10 μg kg-1 for total AFs). AFB1 (31.60 ± 0.22 μg kg-1) had the highest level of contamination, followed by AFB2 (24.40 ± 0.17 μg kg-1) in packed pepper powder. In the adult population, the estimated daily intake (EDI) of AFB1, AFB2, AFG1, and AFG2 ranged from 0.80 to 7.90, 0.04 to 6.10, 0.02 to 1.02, and 0.05 to 0.62  μ g kg-1 body weight (bw) per day, respectively. However, the Margins of Exposure (MOE) values and combined Margin of Exposure (MoET) for these chemicals were significantly lower than the safe margin (<10 000). Therefore, this study highlights the potential health risks associated with consuming AFs-contaminated red peppers and the need for stricter regulations and monitoring to ensure food safety.

Determination and risk assessment of aflatoxin B1 in the kernel of imported raw hazelnuts from Eastern Azerbaijan Province of Iran

Aflatoxin B1 (AFB1) is widespread and seriously threatens public health worldwide. This study aimed to investigate AFB1 in imported hazelnut samples in northwest of Iran (Eastern Azerbaijan Province) using High-Performance Liquid Chromatography with a Fluorescent Detector (HPLC-FLD). In all tested samples AFB1 was detected. The mean concentration of AFB1 was 4.20 μg/kg and ranged from 3.145 to 8.13 μg/kg. All samples contained AFB1 levels within the maximum acceptable limit except for one sample. Furthermore, the human health risk assessment of AFB1 from consuming imported hazelnuts by Iranian children and adults was evaluated based on the margin of exposure (MoE) and quantitative liver cancer risk approaches. The MoE mean for children was 2529.76, while for adults, it was 8854.16, indicating a public health concern. The present study found that the risk of developing liver cancer among Iranian children was 0.11100736 per 100,000 people, and in the Iranian adult population was 0.0314496 cancers per 100,000 people. Since environmental conditions potentially affect aflatoxin levels in nuts, countries are advised to monitor aflatoxin contents in imported nuts, especially from countries with a conducive climate for mold growth.

Smart and emerging point of care electrochemical sensors based on nanomaterials for SARS-CoV-2 virus detection: Towards designing a future rapid diagnostic tool

In the recent years, researchers from all over the world have become interested in the fabrication of advanced and innovative electrochemical and/or biosensors for respiratory virus detection with the use of nanotechnology. These fabricated sensors demonstrated a number of benefits, including precision, affordability, accessibility, and miniaturization which makes them a promising test method for point-of-care (PoC) screening for SARS-CoV-2 viral infection. In order to comprehend the principles of electrochemical sensing and the role of various types of sensing interfaces, we comprehensively explored the underlying principles of electroanalytical methods and terminologies related to it in this review. In addition, it is addressed how to fabricate electrochemical sensing devices incorporating nanomaterials as graphene, metal/metal oxides, metal organic frameworks (MOFs), MXenes, quantum dots, and polymers. We took an effort to carefully compile current developments, advantages, drawbacks, possible solutions in nanomaterials based electrochemical sensors.

The role of ion dissolution in metal and metal oxide surface inactivation of SARS-CoV-2

Anti-viral surface coatings are under development to prevent viral fomite transmission from high-traffic touch surfaces in public spaces. Copper's anti-viral properties have been widely documented, but the anti-viral mechanism of copper surfaces is not fully understood. We screened a series of metal and metal oxide surfaces for anti-viral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease (COVID-19). Copper and copper oxide surfaces exhibited superior anti-SARS-CoV-2 activity; however, the level of anti-viral activity was dependent on the composition of the carrier solution used to deliver virus inoculum. We demonstrate that copper ions released into solution from test surfaces can mediate virus inactivation, indicating a copper ion dissolution-dependent anti-viral mechanism. The level of anti-viral activity is, however, not dependent on the amount of copper ions released into solution per se. Instead, our findings suggest that degree of virus inactivation is dependent on copper ion complexation with other biomolecules (e.g., proteins/metabolites) in the virus carrier solution that compete with viral components. Although using tissue culture-derived virus inoculum is experimentally convenient to evaluate the anti-viral activity of copper-derived test surfaces, we propose that the high organic content of tissue culture medium reduces the availability of "uncomplexed" copper ions to interact with the virus, negatively affecting virus inactivation and hence surface anti-viral performance. We propose that laboratory anti-viral surface testing should include virus delivered in a physiologically relevant carrier solution (saliva or nasal secretions when testing respiratory viruses) to accurately predict real-life surface anti-viral performance when deployed in public spaces.IMPORTANCEThe purpose of evaluating the anti-viral activity of test surfaces in the laboratory is to identify surfaces that will perform efficiently in preventing fomite transmission when deployed on high-traffic touch surfaces in public spaces. The conventional method in laboratory testing is to use tissue culture-derived virus inoculum; however, this study demonstrates that anti-viral performance of test copper-containing surfaces is dependent on the composition of the carrier solution in which the virus inoculum is delivered to test surfaces. Therefore, we recommend that laboratory surface testing should include virus delivered in a physiologically relevant carrier solution to accurately predict real-life test surface performance in public spaces. Understanding the mechanism of virus inactivation is key to future rational design of improved anti-viral surfaces. Here, we demonstrate that release of copper ions from copper surfaces into small liquid droplets containing SARS-CoV-2 is a mechanism by which the virus that causes COVID-19 can be inactivated.

Understanding intentionally and non-intentionally added substances and associated threshold of toxicological concern in post-consumer polyolefin for use as food packaging materials

The use of post-consumer recycled (PCR) polymers in food contact materials (FCMs) can facilitate achieving a circular economy by reducing environmental waste and landfill accumulation. This study aimed to identify potentially harmful substances, including non-intentionally added substances (NIAS) and unapproved intentionally added substances (IAS), in polyolefin samples from material recovery facilities using gas-chromatography mass-spectrometry. Selected phthalates and bisphenols were quantified by targeted gas-chromatography tandem mass-spectrometry. The analysis detected 9 compounds in virgin polymers and 52 different compounds including alcohols, hydrocarbons, phenols in virgin and hydrocarbons, aromatic, phthalates, organic acids, per- and polyfluoroalkyl substances (PFAS) in PCR polymers. The Cramer classification system was used to assesses the Threshold of Toxicological Concern associated with the detected compounds. The PCR sample showed a slightly higher proportion of Cramer Class III compounds (48.08 %) than the virgin sample (44.44 %), indicating higher toxicity potential. Quantification detected bisphenols only in PCR material including BPA (2.88 ± 0.53 μg/g), BPS (5.12 ± 0.003 μg/g), BPF (3.42 ± 0.01 μg/g), and BADGE (4.638 μg/g). Phthalate concentrations were higher in PCR than virgin samples, with the highest levels detected as DIDP, at 6.18 ± 0.31 μg/g for PCR and 6.04 ± 0.02 for virgin. This study provides critical understanding of the safety and potential risks associated with using PCR polyolefins from different sources in food contact applications.

Lithography-free interdigitated electrodes by trench-filling patterning on polymer substrate for Alzheimer's disease detection

Microelectrodes have played a crucial role in electrochemistry for the last few decades. However, the conventional lithographic processes, the key players in fabrication, are nonetheless technologically challenging, pricey, and lack reproducibility. In this work has developed a novel and low-cost patterned-replication fabrication technology for interdigitated electrode array (IDA) electrodes on the polymer substrate. Conventional UV-lithography has been utilized to fabricate the nickel IDA electrode pattern as a master mold on the stainless-steel substrate, which was replicated onto the polymer substrate by the hot-emboss technique. Then, gold was deposited on the replicated wafer by electron beam evaporation, and finally adhesive tape lift-off was used to obtain the gold IDA electrode. The fabricated IDA electrode was applied for electrochemical detection of various p-aminophenol (PAP) concentrations as a representative biomarker with a detection limit of 0.01 nM. Finally, different levels of amyloid beta 42 (Aß42) and amyloid beta aggregated (Aß Agg.), two Alzheimer's disease (AD) biomarkers, were measured using the developed IDA electrode via e-ELISA using enzyme by-products PAP. While quantified, the proposed IDA electrode successfully detects Aß42 and Aß Agg. with the lower detection limit (LOD) of 3.9 and 7.81 pg/ml, respectively.

Ultrasensitive Detection of Hydrogen Peroxide Using Methylene Blue Grafted on Molecular Wires as Nanozyme with Catalase-like Activity

In this study, we present the development of an electrochemical sensor designed for ultrasensitive detection of endogenous H2O2. This sensor relies on signal amplification achieved through nanozyme activity exhibited by methylene blue (MB) grafted onto a peptide support. The sensor exhibited excellent selectivity and sensitivity, with a limit of detection of 18 nM and a linear detection range of 20-200 nM. Thus, we have validated the concept of the MB-peptide system, serving as both an electroactive label and a catalyst for H2O2 decomposition under electrochemical conditions. The implemented signal amplification system enables the rapid detection of H2O2, with an overall assay time of 1-2 min, a significant improvement compared to amperometric detection using surface-immobilized enzymes.

Cleaning technologies integrated in duct flows for the inactivation of pathogenic microorganisms in indoor environments: A critical review of recent innovations and future challenges

Pathogenic microorganisms are a major concern in indoor environments, particularly in sensitive facilities such as hospitals, due to their potential to cause nosocomial infections. This study evaluates the concentration of airborne bacteria and fungi in the University Hospital Complex of Albacete (Spain), comparing the results with recent literature. Staphylococcus is identified as the most prevalent bacterial genus with a percentage distribution of 35%, while Aspergillus represents the dominant fungal genus at 34%. The lack of high Technology Readiness Levels (TRL 6, TRL 7) for effective indoor air purification requires research efforts to bridge this knowledge gap. A screening of disinfection technologies for pathogenic airborne microorganisms such as bacteria and fungi is conducted. The integration of filtration, irradiation or and (electro)chemical gas treatment systems in duct flows is discussed to enhance the design of the air-conditioning systems for indoor air purification. Concerns over microbial growth have led to recent studies on coating commercial fibrous air filters with antimicrobial particles (silver nanoparticles, iron oxide nanowires) and polymeric materials (polyaniline, polyvinylidene fluoride). Promising alternatives to traditional short-wave UV-C energy for disinfection include LED and Far-UVC irradiation systems. Additionally, research explores the use of TiO2 and TiO2 doped with metals (Ag, Cu, Pt) in filters with photocatalytic properties, enabling the utilization of visible or solar light. Hybrid photocatalysis, combining TiO2 with polymers, carbon nanomaterials, or MXene nanomaterials, enhances the photocatalytic process. Chemical treatment systems such as aerosolization of biocidal agents (benzalkonium chloride, hydrogen peroxide, chlorine dioxide or ozone) with their possible combination with other technologies such as adsorption, filtration or photocatalysis, are also tested for gas disinfection. However, the limited number of studies on the use of electrochemical technology poses a challenge for further investigation into gas-phase oxidant generation, without the formation of harmful by-products, to raise its TRL for effectively inactivating airborne microorganisms in indoor environments.

Efficient mapping of lignin depolymerization product pools and quantification of specific monomers through rapid GPC-HPLC-UV/VIS analysis

BACKGROUND

Growing research on lignin depolymerization to functionalized bio-aromatics has necessitated dedicated analysis techniques. However, immense variability in molecular weight and functional groups of the depolymerization products impedes fast analysis of a large number of samples while remaining in-depth enough for catalyst screening or reaction condition optimization. While GPC-HPLC-UV/VIS has been a promising technique, up until now, the information it provides is largely qualitative. By enabling quantification of key monomeric products and through further reduction of overall analysis time, this study aims to increase the potential of GPC-HPLC-UV/VIS for fast and in-depth characterization of lignin depolymerization product pools.

RESULTS

Analysis of selected samples, isolated from GPC-HPLC-UV/VIS analyses of lignin depolymerization product pools, with gas chromatography (GC) equipped with an Orbitrap high-resolution accurate mass spectrometer (Orbitrap-HR/AM-MS) is successful in identifying the main low monomeric products. Moreover, these identifications are further substantiated through GPC-HPLC-UV/VIS analysis of standards. Furthermore, straight forward quantification of these products directly within GPC-HPLC-UV/VIS is successfully developed with limits of detection ≤0.05 mmol/L, which is at least on par with more complex analysis techniques. Additionally, several different reversed phase columns are assessed to reduce 2nd dimension (2D) time and, hence, overall analysis time while maintaining the possibility for quantification. A reduction in overall analysis time of about 30% as compared to the state-of-the-art is achieved by using a YMC Triart BIO C4 column as 2D.

SIGNIFICANCE

Through the enhancements introduced in this study, GPC-HPLC-UV/VIS emerges as a unique technique for the analysis of lignin depolymerization product pools, which is capable of fast yet sufficiently in-depth analysis of a large volume of samples. This capability is indispensable for catalyst screening and fine-tuning reaction conditions.

Layered double hydroxide nanosheets-built porous film-covered Au nanoarrays as enrichment and enhancement chips for efficient SERS detection of trace styrene

Styrene, a prevalent volatile organic compounds (VOCs), is very harmful to atmosphere and humans. Consequently, the development of efficient detection technologies for styrene is of high importance, which is still in challenge! In this work, we crafted a layered double hydroxide (LDH) porous film-coated gold nanoarray, designed to act as a surface enhanced Raman spectroscopy (SERS) chip for the efficient and portable detection of gaseous styrene. This chip features a covering layer composed of cross-linked LDH nanosheets, notable for their porous structure and high specific surface area. When the covering layer is 100-300 nm in thickness, this composite chip has significant enrichment effect and strong SERS performance to gaseous styrene with a lowest detectable concentration below 1 ppb (4.64 ×10-3 mg/m3), and can response within 10 s, showing the rapid response and high sensitivity. Additionally, the chip has strong anti-interference capabilities and maintains excellent response to styrene, even in mixed benzene-VOCs gases. The exceptional SERS performances of this chip is ascribed to its LDH covering layer-induced styrene-enrichment and structurally-enhanced SERS performances. This study provides a simple route and practical chip for the rapid and ultrasensitive SERS-based detection of gaseous styrene, which is also potentially beneficial for the detection of other gaseous VOCs.

Development of a solid phase microextraction method for the determination of nicotine in dried mushrooms

Official control of EU market foodstuffs repeatedly reports high nicotine levels in dried wild mushrooms without any clear scientific consensus about their origin. The advised constant monitoring calls for improvements to existing methods. For this purpose, our aim was to develop a headspace solid phase microextraction (HS-SPME) method coupled to gas chromatography with mass spectrometric detection (GC-MS) that would eliminate the need for extensive sample pre-treatment. The type of fiber coating, amount of sample, extraction temperature and time, desorption time and salt addition were investigated and optimized as parameters affecting the SPME procedure. The optimized conditions were used to validate a quantitative method for nicotine analysis by matrix-matched calibration and isotopically labelled internal standard correction. The method provided good linearity (r2 = 0.9994) over the tested concentration range (0.025-1 mg kg-1), low detection limit (0.005 mg kg-1) and low quantification limit (0.017 mg kg-1) for nicotine, being below the EU foodstuff regulations. For both of the tested concentration levels (0.050 and 0.200 mg kg-1), precision expressed as relative standard deviation was below 10% (4.5% and 8.5%, respectively), while accuracy was 98.2% and 100.3%. The optimized method was then used to determine nicotine levels in 18 samples of dried Boletus mushrooms from southeastern European countries entering the EU market. We demonstrated our HS-SPME procedure to be fast, simple, sensitive, solvent-free, cost-effective and thus suitable for controlling consumer safety regarding nicotine level in dried mushrooms.

Colorimetric Multigas Sensor Arrays and an Artificial Olfactory Platform for Volatile Organic Compounds

Herein, we develop colorimetric multigas sensor arrays assembling chemo-reactive fluorescent patch arrays and 10 × 10 indium gallium zinc oxide phototransistor arrays and apply them to an artificial olfactory platform to recognize five different volatile organic compounds (VOCs). Porous nanofibers, coupled with two organic emitters and emitting fluorescence, rapidly respond to gas-phased VOCs and offer unique fluorescent patterns associated with particular gas conditions, including gas kinds, concentrations, and exposure times by forming patch arrays with different fluorophore component ratios. These VOC-induced fluorescent patterns could be quantified and amplified by indium gallium zinc oxide (IGZO) phototransistor arrays functioning as a signal-generating component, resulting in gas-fingerprint patterns regarding electrical signals. Thus, the pattern library associated with VOCs and their concentration enables us to determine each airborne analyte as the artificial olfactory platform. Therefore, this system could achieve rapid, early quantitative recognition of hazardous gases and be applied as a preventative, portable, and wearable multigas identifier in various fields.

Suitability of MRF Recovered Post-Consumer Polypropylene Applications in Extrusion Blow Molded Bottle Food Packaging

Polypropylene (PP) is one of the most abundant plastics used due to its low price, moldability, temperature and chemical resistance, and outstanding mechanical properties. Consequently, waste from plastic materials is anticipated to rapidly increase with continually increasing demand. When addressing the global problem of solid waste generation, post-consumer recycled materials are encouraged for use in new consumer and industrial products. As a result, the demand is projected to grow in the next several years. In this study, material recovery facility (MRF)-recovered post-consumer PP was utilized to determine its suitability for extrusion blow molded bottle food packaging. PP was sorted and removed from mixed-polymer MRF-recovered bales, ground, trommel-washed, then washed following the Association of Plastics Recyclers' protocols. The washed PCR-PP flake was pelletized then manually blended with virgin PP resin at 25%, 50%, 75, and 100% PCR-PP concentrations and fed into the extrusion blow molding (EBM) machine. The EBM bottles were then tested for physical performance and regulatory compliance (limits of TPCH: 100 μg/g). The results showed an increased crystallization temperature but no practical difference in crystallinity as a function of PCR-PP concentrations. Barrier properties (oxygen and water vapor) remained relatively constant except for 100% MRF-recovered PCR-PP, which was higher for both gas types. Stiffness significantly improved in bottles with PCR-PP (p-value < 0.05). In addition, a wider range of N/IAS was detected in PCR-PP due to plastic additives, food additives, and degradation byproducts. Lastly, targeted phthalates did not exceed the limits of TPCH, and trace levels of BPA were detected in the MRF PCR-PP. Furthermore, the study's results provide critical information on the use of MRF recovered in food packaging applications without compromising performance integrity.

A sensitive and economical method for simultaneous determination of D/L- amino acids profile in foods by HPLC-UV: Application in fermented and unfermented foods discrimination

This work described a sensitive and economical HPLC-UV method with FDAA derivatization to simultaneously detect 36 D/l-amino acids, which provides higher sensitivity and lower cost than other HPLC-based methods. It was validated for linearity range (8-1000 µmol/L), limits of detection (2.68-62.44 pmol/L), limits of quantification (2.93 to 208.13 pmol/L), intraday precision (0.30 % - 5.31 %), interday precision (1.96 % - 8.04 %) and accuracy (86.53 % - 121.46 %). This method was then applied in the determination of D/L- amino acids abundance in fermented and unfermented food materials and showed the characteristics of each type of foods. The method also demonstrated good performance in another application case for the discrimination of different types of food materials based on D/L- amino acids profile. It emphasizes the ability of the method to study the characteristics, distribution and abundance of d-amino acids in foods and their potential application in food quality control.

Simple Immunosensor Based on Carboxyl-Functionalized Multi-Walled Carbon Nanotubes @ Antimony-Doped Tin Oxide Composite Membrane for Aflatoxin B1 Detection

This paper presents a novel nano-material composite membrane for detecting aflatoxin B₁ (AFB₁). The membrane is based on carboxyl-functionalized multi-walled carbon nanotubes (MWCNTs-COOH) @ antimony-doped tin oxide (ATO)-chitosan (CS). To prepare the immunosensor, MWCNTs-COOH were dissolved in the CS solution, but some MWCNTs-COOH formed aggregates due to the intertwining of carbon nanotubes, blocking some pores. ATO was added to the solution containing MWCNTs-COOH, and the gaps were filled by adsorbing hydroxide radicals to form a more uniform film. This greatly increased the specific surface area of the formed film, resulting in a nano-composite film that was modified on screen-printed electrodes (SPCEs). The immunosensor was then constructed by immobilizing anti-AFB₁ antibodies (Ab) and bovine serum albumin (BSA) on an SPCE successively. The assembly process and effect of the immunosensor were characterized using scanning electron microscopy (SEM), differential pulse voltammetry (DPV), and cyclic voltammetry (CV). Under optimized conditions, the prepared immunosensor exhibited a low detection limit of 0.033 ng/mL with a linear range of 1 × 10^-3-1 × 10³ ng/mL. The immunosensor demonstrated good selectivity, reproducibility, and stability. In summary, the results suggest that the MWCNTs-COOH@ATO-CS composite membrane can be used as an effective immunosensor for detecting AFB₁.

Switchable aptamer-fueled colorimetric sensing toward agricultural fipronil exposure sensitized with affiliative metal-organic framework

Persistent usage of pesticides in agriculture has posed serious damage to overall ecosystem and human health, and thereby it is imperative to develop sensitive and efficient tools to evaluate residual pesticides in food and environmental setting. Herein, we reported a switchable colorimetric probe toward fipronil residue sensitized with aptamer-fueled catalytic activity of affiliative ZIF-8. Innovatively, it was found that the attached aptamer preferred to adsorb 3,3',5,5'-tetramethylbenzidine (TMB) rather than 2,2-azinobis (3-ethylbenzothiazo-line-6-sulfonic acid) (ABTS), greatly promoting catalytic oxidation of ZIF-8 toward TMB for further improving sensitivity. Aiding with smartphone-based image acquisition, fipronil-responsive discoloration degree was converted into the ratio of green and blue (G/B) with limit of detection as low as 0.036 μM (0.016 μg·g^-1). Moreover, it allowed for fipronil analysis in water, soil and vegetable samples with good recovery between 87 % and 110 %, verifying extension application prospect of the aptamer-fueled colorimetry for on-field pesticide evaluation in food safety supervision.

Real Time and Spatiotemporal Quantification of pH and H2O2 Imbalances with a Multiplex Surface-Enhanced Raman Spectroscopy Nanosensor

Oxidative stress is involved in many aging-related pathological disorders and is the result of defective cellular management of redox reactions. Particularly, hydrogen peroxide (H2O2), is a major byproduct and a common oxidative stress biomarker. Monitoring its dynamics and a direct correlation to diseases remains a challenge due to the complexity of redox reactions. Sensitivity and specificity are major drawbacks for H2O2 sensors regardless of their readout. Luminiscent boronate-based probes such as 3-mercaptophenylboronic acid (3-MPBA) are emerging as the most effective quantitation tool due to their specificity and sensitivity. Problems associated with these probes are limited intracellular sensing, water solubility, selectivity, and quenching. We have synthesized a boronate-based nanosensor with a surface-enhanced Raman spectroscopy (SERS) readout to solve these challenges. Furthermore, we found out that environmental pH gradients, as found in biological samples, affect the sensitivity of boronate-based sensors. When the sensor is in an alkaline environment, the oxidation of 3-MPBA by H2O2 is more favored than in an acidic environment. This leads to different H2O2 measurements depending on pH. To solve this issue, we synthesized a multiplex nanosensor capable of concomitantly quantifying pH and H2O2. Our nanosensor first measures the local pH and based on this value, provides the amount of H2O2. It seems that this pH-dependent sensitivity effect applies to all boronic acid based probes. We tested the multiplexing ability by quantitatively measuring intra- and extracellular pH and H2O2 dynamics under physiological and pathological conditions on healthy cells and cells in which H+ and/or H2O2 homeostasis has been altered.

Impedimetric nanoimmunosensor platform for aflatoxin B1 detection in peanuts

This article developed a novel electrochemical immunosensor for the specific detection of aflatoxin B1 (AFB1). Amino-functionalized iron oxide nanoparticles (Fe₃ O₄ -NH₂ ) were synthesized. Fe₃ O₄ -NH₂ were chemically bound on self-assembly monolayers (SAMs) of mercaptobenzoic acid (MBA). Finally, polyclonal antibodies (pAb) were immobilized on Fe₃ O₄ -NH₂ -MBA. The sensor system was evaluated through atomic force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). A reduction in the anodic and cathodic peak currents was observed after the assembly of the sensor platform. The charge transfer resistance (R_ct ) was increased due to the electrically insulating bioconjugates. Then, the specific interaction between the sensor platform and AFB1 blocks the electron transfer of the [Fe(CN)₆ ]^3-/4- redox pair. The nanoimmunosensor showed a linear response range estimated from 0.5 to 30 μg/mL with a limit of detection (LOD) of 9.47 μg/mL and a limit of quantification (LOQ) of 28.72 μg/mL for AFB1 identification in a purified sample. In addition, a LOD of 3.79 μg/mL, a LOQ of 11.48 μg/mL, and a regression coefficient of 0.9891 were estimated for biodetection tests on peanut samples. The proposed immunosensor represents a simple alternative, successfully applied in detecting AFB1 in peanuts, and therefore, represents a valuable tool for ensuring food safety.

Mycotoxin Contamination in Hazelnut: Current Status, Analytical Strategies, and Future Prospects

Hazelnuts represent a potential source of mycotoxins that pose a public health issue due to their increasing consumption as food ingredients worldwide. Hazelnuts contamination by mycotoxins may derive from fungal infections occurring during fruit development, or in postharvest. The present review considers the available data on mycotoxins detected in hazelnuts, on fungal species reported as infecting hazelnut fruit, and general analytical approaches adopted for mycotoxin investigation. Prompted by the European safety regulation concerning hazelnuts, many analytical methods have focused on the determination of levels of aflatoxin B1 (AFB1) and total aflatoxins. An overview of the available data shows that a multiplicity of fungal species and further mycotoxins have been detected in hazelnuts, including anthraquinones, cyclodepsipeptides, ochratoxins, sterigmatocystins, trichothecenes, and more. Hence, the importance is highlighted in developing suitable methods for the concurrent detection of a broad spectrum of these mycotoxins. Moreover, control strategies to be employed before and after harvest in the aim of controlling the fungal contamination, and in reducing or inactivating mycotoxins in hazelnuts, are discussed.

ICP-OES assessment of trace and toxic elements in Ziziphora clinopodioides Lam. from Iran by chemometric approaches

The aim of the study was to evaluate the concentrations of some essential and toxic elements (including Ca, K, Mg, Na, Fe, Cu, Mn, Zn, Co, Mo, Pb, Ni, Cr, and Cd) in Ziziphora clinopodioides Lam. (endemic Iranian herb) from 14 different regions by ICP-OES (inductively coupled plasma-optical emission spectrometry) method followed by multivariate statistical analyses. The analytical performances were assessed as the limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy. Multivariate analysis (CA, PCA and HCA) showed the elemental distribution in the roots were higher than the shoots and significant element was Ca between regions. Three principal components (PCs) explained 77.94% of the total variance. They were as follows: PC1 with Cu, Zn, K, Cr, Ni, and Mn; PC2 with Na, Ca, Pb, and Fe; and PC3 with Mg. Hierarchical cluster analysis indicated four groups of Z. clinopodioides samples from the 14 regions based on their trace and toxic element levels. These chemometric approaches with multivariate analysis enable researchers to understand and quantify the relationship between the variables in a data set, and the analysis considers more than one factor. The concentrations of Cu, Na, Mn, Zn, and Pb in most Z. clinopodioides samples were below the WHO (world health organization) limit for herbal medicines (10, 51,340, 200, 50, and 10 µg g^-1 respectively), while Fe and Ca levels were higher than allowed (15 and 614 µg g^-1 respectively). However, the WHO limit for Mg, K, Co, and Mo in medicinal plants has not yet been determined. The results of this study confirmed that different parts of Z. clinopodioides can be used as an important source for human nutrition due to its essential mineral elements.

Toxic metal and trace element status in the breast milk of Turkish new-born mothers

BACKGROUND AND AIM

This study aims to evaluate the toxic metal and trace element concentrations in breast milk obtained from new-born nursing mothers in rural Giresun province, located on the coast of the Black Sea.

METHODS

Milk samples were randomly collected once from early lactation of 50 nursing mothers. Inductively coupled plasma mass spectrometry was used to analyse the concentrations of iron (Fe), nickel (Ni), manganese (Mn), cobalt (Co), chromium (Cr), copper (Cu), zinc (Zn), arsenic (As), molybdenum (Mo), cadmium (Cd) and lead (Pb) in the breast milk. Shapiro-Wilk test was used to evaluate the distribution of data. The Pearson-J correlation was used for normally distributed elements, and Spearman correlation analysis was used for others.

RESULTS

The mean amounts of elements were 3.36 µg kg^-1 of Cr, 9.26 µg kg^-1 of Mn, 797 µg kg^-1 of Fe, 1.99 µg kg^-1 of Ni, 5.92 µg kg^-1 of Cu, 379 µg kg^-1 of Zn and 2.23 µg kg^-1 of Pb. Co, As, Mo and Cd concentrations were below the detection limit. A highly significant correlation was found between iron and Nickel in breast milk.

CONCLUSION

Our findings were evaluated in comparison with the WHO data, and whether they were in accordance with the recommended Dietary Reference Intake (DRI) values for 0-6-months-old infants was calculated. Pb levels were similar to those of WHO, while As and Cd were below the measurable limit. Fe, Mn, and Cr concentrations were higher than WHO data, while Co, Ni, Cu and Zn were lower. This research is the first study conducted in this region.

Chemical Composition, Antibacterial, Antifungal and Antidiabetic Activities of Ethanolic Extracts of Opuntia dillenii Fruits Collected from Morocco

Opuntia dillenii (Ker Gawl.) Haw. belongs to the Cactaceae family and is native to the arid and semi-arid regions of Mexico and the southern United States. O. dillenii are now used as medicinal plants in various countries. In this study, we investigated the chemical composition of ethanolic extracts obtained from seeds, juice, and peel of O. dillenii fruits collected from Morocco, and we evaluated their antibacterial, antifungal, and antidiabetic activities. Phytochemical screening revealed high quantities of polyphenols (193.73 ± 81.44 to 341.12 ± 78.90 gallic acid eq [g/100 g dry weight]) in the extracts. The major phenolic compounds determined by HPLC were gallic acid, vanillic acid, and syringic acid. Regarding flavonoids, quercetin 3-O-β-D-glucoside and kaempferol were the predominant molecules. Juice extracts showed weak to moderate antibacterial activity against the bacteria species Listeria monocytogenes, Escherichia coli, and Salmonella braenderup. All tested extracts displayed a significant inhibitory effect on α-glucosidase and α-amylase activities in vitro, with the peel extracts showing the greatest inhibitory effects. Together, these findings suggest that O. dillenii fruits are a promising source for the isolation of novel compounds with antibacterial or antidiabetic activities. For the most abundant phytochemicals identified in O. dillenii peel ethanolic extract, molecular docking simulations against human pancreatic α-amylase enzyme were performed. These indicated the presence of bioactive compounds in the extract with a better potential to decrease the enzyme activity than the commercial drug acarbose.

Menezes L, Schmidt MA, Maier SA. 3D-Nanoprinted Antiresonant Hollow-Core Microgap Waveguide: An on-Chip Platform for Integrated Photonic Devices and Sensors

Due to their unique capabilities, hollow-core waveguides are playing an increasingly important role, especially in meeting the growing demand for integrated and low-cost photonic devices and sensors. Here, we present the antiresonant hollow-core microgap waveguide as a platform for the on-chip investigation of light-gas interaction over centimeter-long distances. The design consists of hollow-core segments separated by gaps that allow external access to the core region, while samples with lengths up to 5 cm were realized on silicon chips through 3D-nanoprinting using two-photon absorption based direct laser writing. The agreement of mathematical models, numerical simulations and experiments illustrates the importance of the antiresonance effect in that context. Our study shows the modal loss, the effect of gap size and the spectral tuning potential, with highlights including extremely broadband transmission windows (>200 nm), very high contrast resonance (>60 dB), exceptionally high structural openness factor (18%) and spectral control by nanoprinting (control over dimensions with step sizes (i.e., increments) of 60 nm). The application potential was demonstrated in the context of laser scanning absorption spectroscopy of ammonia, showing diffusion speeds comparable to bulk diffusion and a low detection limit. Due to these unique properties, application of this platform can be anticipated in a variety of spectroscopy-related fields, including bioanalytics, environmental sciences, and life sciences.

Tetrazolium-Based Visually Indicating Bacteria Sensor for Colorimetric Detection of Point of Contamination

Protective equipment for detecting bacterial contamination has been in high demand with increasing interest in public health and hygiene. Herein, a fiber-based visually indicating bacteria sensor (VIBS) embedded with iodonitrotetrazolium chloride is developed for the general purpose of detecting live bacteria, and its chromogenic effectiveness is investigated for Gram-negative Escherichia coli and Gram-positive Micrococcus luteus. The developed color intensity is measured by the light absorption coefficient to the scattering coefficient (K/S) based on the Kubelka-Munk equation, and the colorimetric sensitivities of different membranes are examined by calculating the limit of detection (LOD) and the limit of quantification (LOQ). The results demonstrate that the interactions between VIBS and bacteria depend on the wetting properties of membranes. A hydrophobic membrane shows excessive interactions at high concentrations of Gram-negative E. coli bacteria, whose cell membrane is lipophilic. The membrane blended with hydrophobic and hydrophilic polymers displays linear colorimetric responses for both Gram-negative and Gram-positive bacteria strains, demonstrating a reliable sensing capability in the range of the tested bacteria concentration. This study is significant in that explorative experimentations are performed to conceive a proof of concept of a fiber-based bacteria sensor, which is readily applicable in various fields where bacteria pose a threat.

A Validated RP-HPLC Method for Simultaneous Determination of Cefixime and Clavulanic Acid Powder in Pediatric Oral Suspension

A new reverse phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous estimation of pediatric oral powder formulation containing cefixime (CFX) and clavulanic acid (CVA). In this research, an analytical C18 (4.6 mm × 25 cm), 5 μm column was used for chromatographic separation with a mixture of methanol and water containing disodium hydrogen phosphate in ratio of 20 : 80 v/v as the mobile phase (pH 5.5 adjusted with orthophosphoric acid) at a flow rate of 1.0 mL/min. The detecting wavelength and run time were 220 nm and 15 min, respectively. Moreover, the column temperature was maintained at 30°C. The analytical method was validated prior to meeting the conditions specified by International Conference on Harmonization (ICH) and the parameters were specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness, and solution stability. The calibration curve was found to be linear between the concentration ranges of 0.024–0.036 mg/mL and 0.032–0.048 mg/mL for CFX and CVA, respectively. Furthermore, the LOD and LOQ of CFX were 0.0008 and 0.0025 μg/mL, respectively. Accordingly, LOD and LOQ of CVA were 0.0021 and 0.0065 μg/mL, respectively. The accuracy of the optimized method was examined by recovery studies and the mean recovery was observed to be 98.96% and 99.05% for CFX and CVA, respectively, at 100% spiked level. The repeatability testing for both standard and sample solutions revealed that the method is precise within the acceptable range and the %RSD of the precision was <2%. In addition, the findings of specificity, linearity, accuracy, precision, robustness, LOD, LOQ, and solution stability studies of both CFX and CVA were within the criteria of acceptable limit as well.

Enriching intracellular macrolides in Escherichia coli improved the sensitivity of bioluminescent sensing systems

A repressor protein MphR and an enhanced green fluorescent protein (eGFP) were used to construct a bioluminescent sensing system for macrolide analysis in Escherichia coli host cells. We deleted TolC, an efflux pump for macrolides in E. coli, to promote the intracellular accumulation of macrolides. The binding constant (K_1/2) of the sensing system constructed in an E. coli strain was decreased up to 33-fold with deleted TolC, and its sensitivity to the macrolides erythromycin, azithromycin, roxithromycin, and pikromycin was increased. The limit of detection of the bioluminescent sensing system for serum azithromycin was 4.1 nM. The ability to detect serum azithromycin concentrations was confirmed by analyzing photographs using ImageJ software. We also developed a novel sensing system for the immune suppressor FK506, another macrolide that is frequently prescribed. Deleting TolC also significantly improved the sensitivity of this sensing system. Bioluminescent sensing systems constructed in TolC mutants were sensitive to various macrolides, indicating their potential for clinical application with hand-held devices.

Metabolic Investigation on the Interaction Mechanism between Dietary Dihydrochalcone Intake and Lipid Peroxidation Product Acrolein Reduction

SCOPE

Acrolein (ACR), a lipid peroxidation product, pathologically participates in various chronic diseases. In vitro evidence suggestes that dietary dihydrochalcones (DHCs) potentiate safe and alternative therapeutics to synthetic pharmaceuticals for ACR scavenging. Here, to investigate whether ingested DHCs could trap ACR and thereof result in reductions in endogenous ACR in mice is aimed.

METHODS AND RESULTS

Three doses of phloretin (25, 100, and 400 mg kg-1 ), a major dietary DHC, are orally administrated to mice and 24 h urine and fecal samples are collected, respectively. High-resolution MS-based targeted metabolomics reveal for the first time that phloretin and its oxidized metabolite are able to trap endogenous ACR via formation of ACR conjugates. Quantification further demonstrate that a) more than 13% of ingested phloretin can dose-dependently trap 0.77-9.92 nmol of ACR within 24 h; b) phloretin ingestion leads to marked reductions in both free ACR and ACR metabolites in mouse urine compared to control; and c) trapping reactions by phloretin can account for up to 20.1% of the total decreases in endogenous ACR, depending on the administration doses.

CONCLUSION

Findings from this study indicate that regular consumption of DHCs-rich diets holds great promise to alleviate the development of ACR-associated chronic diseases.

Optimization of Determination Method of Cooling Agents in Cigarette Tipping Paper by Gas Chromatography

Monitoring the characteristic components in tipping paper is important to ensure the quality of cigarette products. This study establishes a method based on gas chromatography (GC) for determining cooling agents in tipping paper. The tipping paper was cut into pieces and extracted by ethanol under specific temperatures in a shaker. Then, the characteristic cooling agents of (-)-menthone, L-menthol, and (-)-menthyl lactate in extract were determined using GC coupled with a flame ionization detector (GC-FID). The limits of detection (LODs) and limits of quantification (LOQs) for the three cooling agents ranged from 0.15~0.32 μg/mL and 0.49~1.06 μg/mL, respectively. Results demonstrated a good linear relationship with high correlation coefficients for the three tested cooling agents. The extraction conditions of the cooling agents were optimized through a single-factor experiment as well as an orthogonal experiment. The standard addition recovery experiment showed that the average recoveries range from 81.23 to 100.62%, and the relative standard deviations (RSDs) of the measured values (n = 5) ranged from 0.34 to 1.64%.

How does multiannual plastic mulching in strawberry cultivation influence soil fungi and mycotoxin occurrence in soil?

The production of mycotoxins is often interpreted as fungal response to cope with unfavorable growth conditions induced by toxic substances, environmental and biological factors. Soil covers influence soil environment, which consequently can change the abundance and composition of microbial communities. We investigated how plastic coverage (PC) influence soil fungi and mycotoxin occurrence (deoxynivalenol, nivalenol and zearalenone) compared to the traditional straw coverage (SC) in dependence of soil depth and time in a 3-year field experiment in strawberry cultivation. In total, 300 soil samples, resulting from two treatments, three soil layers, and ten sampling dates (n = 5), were analyzed for mycotoxins and ergosterol (proxy for soil fungal biomass) with liquid chromatography high resolution mass spectrometry and high-performance liquid chromatography with UV-detection, respectively. The modified microclimate under PC had no significant influence on fungal biomass, whereas SC promoted fungal biomass in the topsoil due to C-input. Mycotoxins were detected under both cover types in concentrations between 0.3 and 21.8 µg kg⁻¹, mainly during strawberry establishment period and after fungicide application. Deoxynivalenol had the highest detection frequency with 26.3% (nivalenol: 8.3%, zearalenone: 8.7%). This study confirmed the in situ production of mycotoxins in soil, which seems mainly triggered by field treatment (fungicide application) and plant growth stage (establishment period) rather than on mulching type. Further investigations are necessary to better understand the influence of different agricultural practices and soil types on the production and fate of mycotoxins.

Development of Improved High-Performance Liquid Chromatography Method for the Determination of Residual Caprylic Acid in Formulations of Human Immunoglobulins

Quality control of human immunoglobulin formulations produced by caprylic acid precipitation necessitates a simple, rapid, and accurate method for determination of residual caprylic acid. A high-performance liquid chromatography method for that purpose was developed and validated. The method involves depletion of immunoglobulins, the major interfering components that produce high background noise, by precipitation with acetonitrile (1:1, v/v). Chromatographic analysis of caprylic acid, preserved in supernatant with no loss, was performed using a reverse-phase C18 column (2.1 × 150 mm, 3 μm) as a stationary phase and water with 0.05% TFA–acetonitrile (50:50, v/v) as a mobile phase at a flow rate of 0.2 mL/min and run time of 10 min. The developed method was successfully validated according to the ICH guidelines. The validation parameters confirmed that method was linear, accurate, precise, specific, and able to provide excellent separation of peaks corresponding to caprylic acid and the fraction of remaining immunoglobulins. Furthermore, a 24−1 fractional factorial design was applied in order to test the robustness of developed method. As such, the method is highly suitable for the quantification of residual caprylic acid in formulations of human immunoglobulins for therapeutic use, as demonstrated on samples produced by fractionation of convalescent anti-SARS-CoV-2 human plasma at a laboratory scale. The obtained results confirmed that the method is convenient for routine quality control.

Graphene Oxide/Silver Nanoparticles Platforms for the Detection and Discrimination of Native and Fibrillar Lysozyme: A Combined QCM and SERS Approach

We propose a sensing platform based on graphene oxide/silver nanoparticles arrays (GO/AgNPs) for the detection and discrimination of the native and toxic fibrillar forms of an amyloid-prone protein, lysozyme, by means of a combination of Quartz Crystal Microbalance (QCM) and Surface Enhanced Raman Scattering (SERS) measurements. The GO/AgNPs layer system was obtained by Langmuir-Blodgett assembly of the silver nanoparticles followed by controlled adsorption of GO sheets on the AgNPs array. The adsorption of native and fibrillar lysozyme was followed by means of QCM, the measurements provided the kinetics and the mechanism of adsorption as a function of protein concentration as well as the mass and thickness of the adsorbed protein on both nanoplatforms. The morphology of the protein layer was characterized by Confocal Laser Scanning Microscopy experiments on Thioflavine T-stained samples. SERS experiments performed on arrays of bare AgNPs and of GO coated AgNP after native, or fibrillar, lysozyme adsorption allowed for the discrimination of the native form and toxic fibrillar structure of lysozyme. Results from combined QCM/SERS studies indicate a general construction paradigm for an efficient sensing platform with high selectivity and low detection limit for native and amyloid lysozyme.

Evaluation of a GC-MS method for benzyl chloride content in processed food, meats, and marine products distributed in Korea

Benzyl chloride is a harmful chemical that contaminates air, water, and food. A static headspace GC-MS method for determining benzyl chloride in food was developed and validated. Two food matrices (fat/oil and chicken) were used for method validation. Sample preparation involved ultrasonication extraction and purification (syringe filtration). Linearity (R ²) was > 0.99, accuracy ranged from 86.91% to 110%, the limit of detection was 0.04-0.17 mg/kg, and the limit of quantification was 0.13-0.52 mg/kg. Recovery varied from 88.19% to 111.77%, and precision ranged from 0.10% to 1.17% in intraday and interday analyses. Among 102 food items (oils, fats, meat, marine, and egg products) distributed in Korea, benzyl chloride was only detected in six of the marine products. The validated analytical method can be used for routine monitoring of benzyl chloride residues in food and thereby prevent the human health risks associated with the consumption of food contaminated with this chemical.

Rapid green analytical methodology for simultaneous biomonitoring of five toxic areca nut alkaloids using UHPLC-MS/MS for predicting health hazardous risks

Areca nut (AN) is a fundamental component of betel quid (BQ), an addictive and carcinogenic mixture chewed by hundreds of millions of people in India-Asia-Pacific. Chewing of BQ is associated with oral cancers due to specific carcinogenic alkaloids (arecaidine, guvacine, guvacoline, arecoline, N-Nitrosoguvacoline) in AN. To predict the hazardous health risks of short and long-term chewing of BQ, it is crucial to identify five toxic AN alkaloids in saliva and urine of BQ chewers. This study reports a green analytical methodology comprising in-syringe assisted vortex-induced salt-enhanced liquid-liquid microextraction coupled with ultra-HPLC-MS/MS for simultaneous biomonitoring of five AN alkaloids in saliva and urine. The analytical method validation results exhibited good linearities between 0.05 and 1000 ng mL^-1 with r² > 0.9930. The detection and quantification limits were between 0.01 and 1.5 and 0.05-5 ng mL^-1. Relative recoveries ranged between 87.9% and 110.1% with RSD < 9.1% for saliva samples, 81.5-115.1% with RSD < 9.7% for urine samples. The results indicated the successful identification and real-time monitoring of concentrations of five target AN alkaloids in saliva and urine of BQ chewers and demonstrated the utility of this technique as an efficient analytical protocol for routine biomonitoring of levels of toxic AN alkaloids from BQ chewers and to predict the exposure level and its harmful health risk.

Early detection of cannabinoids in biological samples based on their affinity interaction with the growth hormone secretagogue receptor

Herein we report on the early detection of cannabinoids in urine samples according to their affinity profiles in competitive assays with labelled ghrelin (GHR). We have demonstrated for the first time that cannabidiol (CBD) and 11-nor-Δ⁹-tetrahydrocannabinol-9-carboxylic acid (carboxy-THC) act as extracellular ligands for the growth hormone secretagogue receptor (GHS-R1a), strongly promoting the binding of ghrelin (GHR), the endogenous ligand of GHS-R1a. The affinity profiles of CBD and carboxy-THC are significantly different from the profiles of synthetic GHR mimetics such as CJC-1295 or [D-Arg¹-D-Phe⁵-D-Trp^7,9-Leu¹¹]-Substance P peptides, which are the most common interferents; the cannabinoids promoted the GHR/GHS-R1a interaction, while the ghrelin mimetics acted rather as competitive inhibitors. The analysis of 1:4 diluted urine samples proved that the proposed method displays good linearity and sensitivity in the range of 5-30 ng/mL for both CBD and carboxy-THC, whereas GHR mimetics display no interference at concentrations up to 100 ng/mL. The results were validated by comparison with the gas chromatography tandem mass spectrometry reference method. CBD may exert the same promoting effect on the interaction of GHS-R1a with other GHR mimetics listed as performance-enhancing substances.

Multi-residue analysis of fifty pesticides in river waters and in wastewaters

Three sampling campaigns were performed in the Lis River (Leiria, Portugal) in February of 2018, November of 2018, and May of 2019. River water and wastewater (influent and effluent) samples of two wastewater treatment plants were target of the study. A total of 25 samples were collected and 50 pesticides were monitored, including organochlorines, triazines, pyrethroids, and organophosphorus, among others. Most of the detected pesticides were insecticides and mainly organochlorines. Concentrations between 1.29 and 2134 ng/L were found. Aldrin, γ-HCH, and cypermethrin were detected in some samples in μg/L, being γ-HCH the pesticide most frequently detected with concentration in μg/L level. The pesticides with the highest detection frequency were (i) cypermethrin, HCB, methoxychlor, and ζ-HCH in river waters; (ii) isoproturon, cypermethrin, methoxychlor, pyrimethanil, γ-HCH, dieldrin, diuron, α-HCH, and α-endosulfan in effluents; and (iii) diuron and isoproturon in influents. The detection of the organochlorides and their degradation products is a consequence of their persistence in the environment, as their usage has long been prohibited in the European Union. Pesticides were grouped by their types in herbicides, insecticides, or fungicides and the detection and concentration for each type were discussed with the climatic conditions. Pesticide toxicity index was determined in the samples collected in the river.

Formulation and development of Serratiopeptidase enteric coated tablets and analytical method validation by UV Spectroscopy

Serratiopeptidase (SRP) is a proteolytic enzyme that emerged as one of the most potent anti-inflammatory and analgesic drugs. The purpose of the present study was to formulate and evaluate enteric-coated tablets for SRP and investigate their stability using a simple and validated analytical method by ultraviolet (UV) spectroscopy. The colloidal silicon dioxide (2.50%), sodium starch glycolate (3.44%), and crospovidone (2.50%) were used as appropriate excipients for the development of core part of tablets. To protect the prepared tablets from acidic environment in the stomach, white shellac, castor oil, HPMC phthalate 40, and ethyl cellulose were used. The seal coating and enteric coating attained were 2.75% and 6.74%, respectively. SRP was found to be linear at 265 nm in the concentration range of 25–150 µg/mL. The results revealed that our developed method was linear (R² = 0.999), precise (RSD % = 0.133), and accurate (% recovery = 99.96–103.34). The formulated SRP tablets were found to be stable under accelerated conditions as well as under room temperature for 6 months (assay %: >97.5%). The in vitro drug release study demonstrated that enteric-coated tablets were able to restrict SRP release in both acidic environments: 0.1 N HCl and simulated gastric fluid (pH 1.2). Moreover, at 60 minutes, the formulated SRP tablets revealed 13.0% and 8.98% higher drug release in phosphate buffer (pH 6.8) and simulated intestinal fluid (pH 6.8), respectively, compared to the marketed tablet formulation. This study concludes that enteric-coated tablets of SRP with higher drug release in the intestine can be prepared and examined for their stability using validated analytical technique of UV spectroscopy.

High performance thin layer chromatography-densitometry method based on picosecond laser-induced fluorescence for the analysis of thioridazine and its photoproducts

A densitometry method based on steady-state and time-resolved fluorescence assessments for thioridazine and its photoproducts applied on HPTLC plates has been developed. The excitation source was a picosecond diode laser emitting at 375 nm. This method was used for the analysis of the photoproducts resulted from thioridazine irradiation with 266 nm nanosecond-pulsed laser. The validation of the developed method was performed for thioridazine in terms of linearity, precision, limits of detection and quantification. Furthermore, analysis of the photoproducts of irradiated thioridazine was performed by steady-state and time-resolved fluorescence. The fluorescence spectra and fluorescence lifetime of each photoproduct were obtained and the horizontal chromatograms of fluorescence maxima were generated.