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Analytica, Volume 4, Issue 2 (June 2023) – 13 articles

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14 pages, 5699 KiB  
Article
Gold Nanoparticles: A Didactic Step-by-Step of the Synthesis Using the Turkevich Method, Mechanisms, and Characterizations
by Ana Elisa F. Oliveira, Arnaldo César Pereira, Mayra A. C. Resende and Lucas Franco Ferreira
Analytica 2023, 4(2), 250-263; https://doi.org/10.3390/analytica4020020 - 08 Jun 2023
Cited by 11 | Viewed by 9836
Abstract
In this study, gold nanoparticles (AuNPs) were synthesized using the Turkevich method. This article explains the didactic step-by-step synthesis, showing pictures of the entire process, including a well-explained mechanism and characterization study. Synthesis involves the reduction of NaAuCl4 using sodium citrate at [...] Read more.
In this study, gold nanoparticles (AuNPs) were synthesized using the Turkevich method. This article explains the didactic step-by-step synthesis, showing pictures of the entire process, including a well-explained mechanism and characterization study. Synthesis involves the reduction of NaAuCl4 using sodium citrate at high temperatures (approximately 90 °C). The two main mechanisms used to explain AuNPs synthesis via the Turkevich method are also discussed. The first mechanism considers that a nanowire intermediary and the other proposes that aggregate intermediates are not formed at any time during the synthesis. The materials (NaAuCl4 and AuNPs) were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and dynamic light scattering (DLS). The UV-Vis spectrum exhibits an absorption maximum at 521 nm because of the surface plasmon resonance (SPR) absorption band of the AuNPs. The SEM images of NaAuCl4 show crystals with cubic shapes, while the AuNPs have an average particle size of approximately 16–25 nm and particles that appear mainly spherical. To confirm the particle shapes, AFM was conducted, and it was possible to clearly observe individual spherical nanoparticles and their aggregates, and the average diameter of these AuNPs was approximately 12–19 nm. The XRD pattern of AuNPs showed four main characteristic peaks corresponding to the (111), (200), (220), and (311) planes, confirming the presence of cubic (FCC) gold. The DLS presented an average particle size of 3.3 ± 0.9 nm and a polydispersity index (PDI) of 0.574. AuNPs were synthesized using a simple and rapid method. The resulting spherical and ultra-small particles can be used in several applications. Full article
(This article belongs to the Section Electroanalysis)
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11 pages, 2261 KiB  
Article
Iodoform Reaction-Based Turbidimetry for Analysis of Alcohols in Hand Sanitizers
by Chirapha Prakobdi and Phoonthawee Saetear
Analytica 2023, 4(2), 239-249; https://doi.org/10.3390/analytica4020019 - 08 Jun 2023
Viewed by 3723
Abstract
This work presents the first development of an analytical turbidimetric method for the determination of legal alcohols in alcohol-based hand sanitizer products. A typical iodoform reaction is exploited to form a yellow product in the form of precipitates. An iodoform test shows a [...] Read more.
This work presents the first development of an analytical turbidimetric method for the determination of legal alcohols in alcohol-based hand sanitizer products. A typical iodoform reaction is exploited to form a yellow product in the form of precipitates. An iodoform test shows a positive result as yellow precipitates in the presence of ethanol and isopropanol; therefore, the test can only be used to distinguish between methanol and those legal alcohols. In the presence of molecular iodine (I2) and a strong alkaline solution, the legal alcohol is converted to the corresponding carbonyl compound (i.e., ethanol to acetaldehyde, isopropanol to acetone). The susceptibility of this intermediate towards the reaction with hydroxide ions (strong alkaline condition) results in formations of yellow precipitation of iodoform (CHI3) and a water-soluble carboxylate salt in the solution. Therefore, this change allows for the detection of legal alcohols through either naked-eye observation (as semi-quantitative analysis) or a common benchtop/portable photometer/spectrophotometer (as quantitative analysis) by means of turbidimetric analysis. In this work, turbidimetry is employed, which is a useful alternative detection method in analytical practice, especially with colored samples in hand sanitizing products. This is because they can employ wavelengths at which the colored solution does not absorb light. As a result of our developed method, the calibration plots are in the range of 30 to 100% (v/v) for both ethanol and isopropanol. The limit of detection (LOD) (3SD of y-intercept/slope) was found to be 7.4% (v/v) ethanol and 6.5% (v/v) isopropanol. Direct analysis of the non-pretreatment of the sample is achieved. The results indicate that our new proposed analytical method is fit for purpose and valid to detect the legal alcohols in alcohol-based hand sanitizing products for both international and Thai regulations (at least 70% (v/v)). Our quantitative results were also comparable to a standard analytical method, such as the use of a gas chromatography-flame ionization detector (GC-FID). Our developed method and analytical operation could potentially be developed into a practically portable analysis. Full article
(This article belongs to the Section Spectroscopy)
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8 pages, 1520 KiB  
Communication
Combining Near-Infrared (NIR) Analysis and Modelling as a Fast and Reliable Method to Determine the Authenticity of Agarwood (Aquilaria spp.)
by Esther K. Grosskopf, Monique S. J. Simmonds and Christopher J. Wallis
Analytica 2023, 4(2), 231-238; https://doi.org/10.3390/analytica4020018 - 07 Jun 2023
Cited by 1 | Viewed by 1388
Abstract
The resinous wood produced by the Aquilaria and Gyrinops species—agarwood—is both rare and highly valuable. It is used in products from perfumes to medicines and has an estimated global market value of $32 billion. As a result, the adulteration and illegal purchasing of [...] Read more.
The resinous wood produced by the Aquilaria and Gyrinops species—agarwood—is both rare and highly valuable. It is used in products from perfumes to medicines and has an estimated global market value of $32 billion. As a result, the adulteration and illegal purchasing of agarwood is widespread and of specific concern to enforcement agencies globally. Therefore, it is of interest to have a fast, reliable, and user-friendly method to confirm the authenticity of a sample of agarwood. We investigated the use of near infrared (NIR) data to develop a method that rapidly distinguished between authentic and non-authentic agarwood samples, based upon a soft independent model of class analogy (SIMCA), using software specific to the application of infrared data to material authentication. The model showed a clear distinction between the authentic and non-authentic samples. However, the small values involved led to poor automatic validation results. Full article
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14 pages, 2571 KiB  
Article
An Open-Source, Low-Cost Apparatus for Conductivity Measurements Based on Arduino and Coupled to a Handmade Cell
by Giovanni Visco, Emanuele Dell’Aglio, Mauro Tomassetti, Luca Ugo Fontanella and Maria Pia Sammartino
Analytica 2023, 4(2), 217-230; https://doi.org/10.3390/analytica4020017 - 02 Jun 2023
Viewed by 2294
Abstract
Electrical conductivity is one of the main parameters for the characterization of water solutions and for the monitoring of water sources. In this paper, we describe a very inexpensive prototype for conductivity measurements based on Arduino UNO R3 coupled to an open-source circuit [...] Read more.
Electrical conductivity is one of the main parameters for the characterization of water solutions and for the monitoring of water sources. In this paper, we describe a very inexpensive prototype for conductivity measurements based on Arduino UNO R3 coupled to an open-source circuit board with only passive components. We designed the printed circuit board (PCB) and the suitable handmade cell using stainless-steel electrodes and wrote the freeware management software; the assembly of the prototype, including a temperature probe, and results were relatively simple. In order to allow for replicates, the instrument design, schematics, and software are available with an open-source license. Thirty-one bottles of spring waters with conductivities of between 15.2 and 2000 µS cm−1 were tested using both this prototype and a commercial conductivity meter. Data correlation produced an equation that allowed us to obtain the conductivity value, starting with the value furnished by the Arduino apparatus in arbitrary units. The prototype is accurate enough (inaccuracy lower than 6% excluding very low conductivity values) and precise (RSD% of about 5%). Even if a lot of commercial instruments for conductivity are available, we propose a prototype built with the aim of lowering the cost of measurements, while ensuring that they remain useful for lab or in situ application, as well as for continuous water monitoring/management systems. A further aim was to propose the building of the instrument as a laboratory exercise; this can help students to better understand basic theoretical concepts regarding conductivity, electronic components, and the acquisition and treatment of analytical data. Full article
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11 pages, 2257 KiB  
Article
Predicting SARS-CoV-2 Variant Using Non-Invasive Hand Odor Analysis: A Pilot Study
by Vidia A. Gokool, Janet Crespo-Cajigas, Andrea Ramírez Torres, Liam Forsythe, Benjamin S. Abella, Howard K. Holness, Alan T. Charlie Johnson, Richard Postrel and Kenneth G. Furton
Analytica 2023, 4(2), 206-216; https://doi.org/10.3390/analytica4020016 - 22 May 2023
Viewed by 1610
Abstract
The adaptable nature of the SARS-CoV-2 virus has led to the emergence of multiple viral variants of concern. This research builds upon a previous demonstration of sampling human hand odor to distinguish SARS-CoV-2 infection status in order to incorporate considerations of the disease [...] Read more.
The adaptable nature of the SARS-CoV-2 virus has led to the emergence of multiple viral variants of concern. This research builds upon a previous demonstration of sampling human hand odor to distinguish SARS-CoV-2 infection status in order to incorporate considerations of the disease variants. This study demonstrates the ability of human odor expression to be implemented as a non-invasive medium for the differentiation of SARS-CoV-2 variants. Volatile organic compounds (VOCs) were extracted from SARS-CoV-2-positive samples using solid phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC–MS). Sparse partial least squares discriminant analysis (sPLS-DA) modeling revealed that supervised machine learning could be used to predict the variant identity of a sample using VOC expression alone. The class discrimination of Delta and Omicron BA.5 variant samples was performed with 95.2% (±0.4) accuracy. Omicron BA.2 and Omicron BA.5 variants were correctly classified with 78.5% (±0.8) accuracy. Lastly, Delta and Omicron BA.2 samples were assigned with 71.2% (±1.0) accuracy. This work builds upon the framework of non-invasive techniques producing diagnostics through the analysis of human odor expression, all in support of public health monitoring. Full article
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24 pages, 1374 KiB  
Review
Review on Biomass Pyrolysis with a Focus on Bio-Oil Upgrading Techniques
by Daniel Lachos-Perez, João Cláudio Martins-Vieira, Juliano Missau, Kumari Anshu, Odiri K. Siakpebru, Sonal K. Thengane, Ana Rita C. Morais, Eduardo Hiromitsu Tanabe and Daniel Assumpção Bertuol
Analytica 2023, 4(2), 182-205; https://doi.org/10.3390/analytica4020015 - 20 May 2023
Cited by 9 | Viewed by 3936
Abstract
This review provides insights into the current research on pyrolytic bio-oil obtained from different feedstock regarding upgrading techniques and applications such as energy, fuels, chemicals, and carbon materials. Raw bio-oil is not appropriate for transportation and ignition due to undesired properties; therefore, several [...] Read more.
This review provides insights into the current research on pyrolytic bio-oil obtained from different feedstock regarding upgrading techniques and applications such as energy, fuels, chemicals, and carbon materials. Raw bio-oil is not appropriate for transportation and ignition due to undesired properties; therefore, several challenges have been reported regarding its suitable market application. For liquid biofuel production, thermochemical pathways, particularly hydrogenation and deoxygenation, must be carried out, and for chemical production, liquid solvents are mostly used via physical separation. The main issues related to downstream processes with environmental and economic assessment are also covered. The analysis indicates that the major bottlenecks for commercial applications of upgraded bio-oil are the initial stage (upgrading techniques), high production costs, and pilot scale production. Finally, future directions are addressed for the improvement of bio-oil upgrading. Full article
(This article belongs to the Section Thermal Analysis)
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12 pages, 3988 KiB  
Article
A Wearable Patch Sensor for Simultaneous Detection of Dopamine and Glucose in Sweat
by Yue Sun, Junjie Ma, Yuwei Wang, Sen Qiao, Yihao Feng, Zhanhong Li, Zifeng Wang, Yutong Han and Zhigang Zhu
Analytica 2023, 4(2), 170-181; https://doi.org/10.3390/analytica4020014 - 10 May 2023
Cited by 3 | Viewed by 2886
Abstract
Achieving quantification of biomarkers in body fluids is crucial to the indication of the state of a person’s body and health. Wearable sensors could offer a convenient, fast and painless sensing strategy. In this work, we fabricated a wearable electrochemical patch sensor for [...] Read more.
Achieving quantification of biomarkers in body fluids is crucial to the indication of the state of a person’s body and health. Wearable sensors could offer a convenient, fast and painless sensing strategy. In this work, we fabricated a wearable electrochemical patch sensor for simultaneous detection of dopamine and glucose in sweat. The sensor was printed on a flexible PDMS substrate with a simple screen-printed method. This prepared four-electrode sensor integrated two working electrodes for dopamine and glucose electrochemical sensing, one Ag/AgCl reference electrode and one carbon counter electrode, respectively. Cyclic voltammetry, differential pulse voltammetry and chronoamperometry were used for the evaluation of the wearable electrochemical patch sensor. It exhibits good sensitivity, wide linear range, low limit of detection, good anti-interference and reproducibility toward dopamine and glucose sensing in PBS and sweat. Full article
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11 pages, 2310 KiB  
Article
Voltammetric Determination of Trimethoprim Using a Glassy Carbon Electrode Modified with Printex(6L) Carbon and Gold Nanoparticles
by Maria H. A. Feitosa, Anderson M. Santos, Ademar Wong, Robson S. Rocha and Fernando C. Moraes
Analytica 2023, 4(2), 159-169; https://doi.org/10.3390/analytica4020013 - 01 May 2023
Cited by 1 | Viewed by 1696
Abstract
This work proposes a simple, fast and low-cost voltammetric method for the determination of trimethoprim at low concentrations in an analytical and real matrix (river water sample, bovine serum and synthetic urine). For this, a glassy carbon electrode was modified with Printex(6L) carbon [...] Read more.
This work proposes a simple, fast and low-cost voltammetric method for the determination of trimethoprim at low concentrations in an analytical and real matrix (river water sample, bovine serum and synthetic urine). For this, a glassy carbon electrode was modified with Printex(6L) carbon and gold nanoparticles in a chitosan film crosslinked with epichlorohydrin. After that, the electrochemical measurement system contained a solution of phosphate buffer at pH 4.0 with commands for the square wave voltammetry technique. The results achieved showed a limit of detection equal to 12.4 nmol L−1 and a linear concentration range from 0.20 to 6.0 μmol L−1. The sensor selectivity was tested in the presence of various electroactive molecules, and the results showed that the detection of TMP in the presence of possible interferents was not masked. In addition, the applicability of the AuNPs–Printex(6L)–CTS:EPH/GCE sensor was also verified in synthetic samples of urine, bovine serum and river water through standard addition and recovery tests. Finally, the results of this analytical proposal portray a simple, fast and efficient method for the detection of TMP in different matrices. Full article
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18 pages, 2064 KiB  
Article
Ximenia americana L.: Chemical Characterization and Gastroprotective Effect
by Renata Torres Pessoa, Isabel Sousa Alcântara, Lucas Yure Santos da Silva, Roger Henrique Souza da Costa, Tarcísio Mendes Silva, Cícera Datiane de Morais Oliveira-Tintino, Andreza Guedes Barbosa Ramos, Maria Rayane Correia de Oliveira, Anita Oliveira Brito Pereira Bezerra Martins, Bruna Caroline Gonçalves Vasconcelos de Lacerda, Edlane Martins de Andrade, Jaime Ribeiro-Filho, Clara Mariana Gonçalves Lima, Henrique Douglas Melo Coutinho and Irwin Rose Alencar de Menezes
Analytica 2023, 4(2), 141-158; https://doi.org/10.3390/analytica4020012 - 30 Apr 2023
Viewed by 1684
Abstract
Ximenia americana L., popularly known in Brazil as “ameixa do-mato, ameixa-brava, and ameixa-do-sertão,” is widely used in folk medicine to treat several intestinal disorders. The present study assessed the potential mechanisms of action underlying the gastroprotective activity of the hydroethanolic extract of Ximenia [...] Read more.
Ximenia americana L., popularly known in Brazil as “ameixa do-mato, ameixa-brava, and ameixa-do-sertão,” is widely used in folk medicine to treat several intestinal disorders. The present study assessed the potential mechanisms of action underlying the gastroprotective activity of the hydroethanolic extract of Ximenia americana L. (EHXA) stem bark. The acute toxicity of EHXA was estimated, and later, the gastroprotective effect in mice was assessed through acute models of gastric lesions induced by acidified or absolute ethanol and indomethacin, where the following mechanisms were pharmacologically analyzed: the involvement of prostaglandins (PG), histamine (H2) receptors, ATP-dependent potassium channels, sulfhydryl groups (SH), α2 adrenergic receptors, nitric oxide (NO), myeloperoxidase (MPO), gastric mucus production, and acetylcholine-mediated intestinal motility. Regarding toxicity, EHXA did not cause deaths or signs of toxicity (LD50 greater than or equal to 2000 mg/kg/p.o.). When the gastroprotective effect was assessed, EHXA (50, 100, and 200 mg/kg/p.o.) reduced the rate of lesions induced by acidified ethanol by 65.63; 53.66, and 58.02% in absolute ethanol at 88.91, 78.82, and 74.68%, respectively, when compared to the negative control group. In the indomethacin-induced gastric injury model, the reductions were 84.69, 55.99, 55.99, and 42.50%, respectively. The study revealed that EHXA might stimulate mucus production and reduce intestinal motility through SH groups, NO production, and activation of α2 adrenergic receptors. The results indicated that EHXA had significant gastroprotective activity in the evaluated models. However, further investigation is required to elucidate the cellular and molecular events underlying the action of EHXA components and to correlate them with the modulation of the signaling pathways, as demonstrated by the current pharmacological approach. Therefore, the results demonstrated in the present study, as well as previously reported findings, support the recommendation of using this species in traditional communities in Brazil. Full article
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15 pages, 1706 KiB  
Article
Modified Cassava Starches’ Identification through Mid-Infrared Spectroscopy and Exploratory Analysis
by Isaac Yves Lopes de Macêdo, Nathalie Dupuy, Vitor H. dos S. Brito, Eric de Souza Gil, Giovanna N. de M. e Silva, Emily K. G. Moreno, Ivo M. Demiate and Marney P. Cereda
Analytica 2023, 4(2), 126-140; https://doi.org/10.3390/analytica4020011 - 24 Apr 2023
Viewed by 1823
Abstract
Different starch properties may cause alterations in the foodstuff’s external appearance. However, modification processes in starches are usually secretive. The use of chemically modified starches is regulated by international standards, which makes it important to identify its presence and type. Mid-infrared spectroscopy (MIR)-modified [...] Read more.
Different starch properties may cause alterations in the foodstuff’s external appearance. However, modification processes in starches are usually secretive. The use of chemically modified starches is regulated by international standards, which makes it important to identify its presence and type. Mid-infrared spectroscopy (MIR)-modified starches’ identification can be hindered by the presence of excess glucose. This research investigates types of modification in commercial starches and in approaches that circumvent MIR’s limitations with exploratory analysis. It also considers that enzymatic hydrolysis (α-amylase and amyloglucosidase) can highlight the points of modification in the structure, which can be detected with infrared assays. To determine if sour cassava starch (FCS) is modified and check its type, six samples were selected: a native one, three of the most common cassava modified starches (etherified, esterified, and FCS), and two laboratory processed samples (Acid, Oxidized). The results showed that the sour cassava starch showed similarities with a commercial ester and an oxidized cassava starch, which may be due to the formation of a graft, corresponding to what the literature has already reported for corn starch treated with lactic acid and gamma radiation. Full article
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13 pages, 1684 KiB  
Article
Revealing the Ion Chemistry Occurring in High Kinetic Energy-Ion Mobility Spectrometry: A Proof of Principle Study
by Florentin Weiss, Christoph Schaefer, Stefan Zimmermann, Tilmann D. Märk and Chris A. Mayhew
Analytica 2023, 4(2), 113-125; https://doi.org/10.3390/analytica4020010 - 23 Apr 2023
Viewed by 1439
Abstract
Here, we present proof of principle studies to demonstrate how the product ions associated with the ion mobility peaks obtained from a High Kinetic Energy-Ion Mobility Spectrometer (HiKE-IMS) measurement of a volatile can be identified using a Proton Transfer Reaction/Selective Reagent Ion-Time-of-Flight-Mass Spectrometer [...] Read more.
Here, we present proof of principle studies to demonstrate how the product ions associated with the ion mobility peaks obtained from a High Kinetic Energy-Ion Mobility Spectrometer (HiKE-IMS) measurement of a volatile can be identified using a Proton Transfer Reaction/Selective Reagent Ion-Time-of-Flight-Mass Spectrometer (PTR/SRI-ToF-MS) when operating both instruments at the same reduced electric field value and similar humidities. This identification of product ions improves our understanding of the ion chemistry occurring in the ion source region of a HiKE-IMS. The combination of the two analytical techniques is needed, because in the HiKE-IMS three reagent ions (NO+, H3O+ and O2+•) are present at the same time in high concentrations in the reaction region of the instrument for reduced electric fields of 100 Td and above. This means that even with a mass spectrometer coupled to the HiKE-IMS, the assignment of the product ions to a given reagent ion to a high level of confidence can be challenging. In this paper, we demonstrate an alternative approach using PTR/SRI-ToF-MS that allows separate investigations of the reactions of the reagent ions NO+, H3O+ and O2+•. In this study, we apply this approach to four nitrile containing organic compounds, namely acetonitrile, 2-furonitrile, benzonitrile and acrylonitrile. Both the HiKE-IMS and the PTR/SRI-ToF-MS instruments were operated at a commonly used reduced electric field strength of 120 Td and with gas flows at the same humidities. Full article
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11 pages, 2215 KiB  
Article
Impacts of Chlorine on the Change of Chlorophyll Fluorescence Spectrum to Phaeodactylum tricornutum
by Na Li, Shimeng Chen, Jun Yang, Jun Song and Yongxin Song
Analytica 2023, 4(2), 102-112; https://doi.org/10.3390/analytica4020009 - 11 Apr 2023
Cited by 1 | Viewed by 1805
Abstract
Chlorine-containing disinfectants have been widely used all over the world to prevent COVID-19. However, little is known about the potential risk of chlorine-containing disinfectants in the marine environment. Phaeodactylum tricornutum (P. tricornutum) is a typical marine economic diatom, often used as [...] Read more.
Chlorine-containing disinfectants have been widely used all over the world to prevent COVID-19. However, little is known about the potential risk of chlorine-containing disinfectants in the marine environment. Phaeodactylum tricornutum (P. tricornutum) is a typical marine economic diatom, often used as an effective biomarker in ecotoxicology research. Here, the present study has investigated the effect of different effective chlorine concentrations on photosynthesis of P. tricornutum by chlorophyll fluorescence spectroscopy. Results have demonstrated that chlorine exposure promoted the chlorophyll fluorescence intensity at initial stage (24 h), suggesting that a large amount of energy is emitted in the form of fluorescence. However, the chlorophyll fluorescence intensity could not be detected under the high effective chlorine concentrations (6.7 × 10−3, 1.0 × 10−2, 1.3 × 10−2 and 1.7 × 10−2 mg L−1) after 48 h, indicating that the chlorine had high toxicity leading to the death of microalgae. In addition, the emission spectra of P. tricornutum were determined to contain two distinct fluorescence peaks representing the core antenna of photosystem II (685 nm) and the photosystem I complexes (710 nm) in the control group. The fluorescence emission peak value at 685 nm is significantly lower than the peak value at 710 nm in the control group, whereas chlorine treatments were opposite. It can be concluded that microalgae can regulate the distribution of excitation energy between the two photosystems to ensure that algae can utilize light energy. The result also found that the peak position of fluorescence emission spectra has a blue shift in all of NaClO treatments. The fluorescence intensity of microalgae excited at 467 nm was lower than that at 439 nm in chlorine treatments, illustrating chlorophyll b antenna was more easily damaged than chlorophyll a antenna. Our findings are providing new insights into the changing mechanism of chlorophyll fluorescence on P. tricornutum under chlorine stress and valuable data for risk assessment of marine environments. Full article
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18 pages, 2567 KiB  
Article
New Approaches in Electroanalytical Determination of Triazines-Based Pesticides in Natural Waters
by Fernanda C. O. L. Martins and Djenaine De Souza
Analytica 2023, 4(2), 84-101; https://doi.org/10.3390/analytica4020008 - 31 Mar 2023
Viewed by 1204
Abstract
This study describes the preparation and use of a dental amalgam electrode for the voltammetric determination of triazine-based pesticides ametryn, atrazine, and simazine in natural waters, using square wave voltammetry. The experimental and voltammetric parameters were previously optimized, and analytical curves were constructed [...] Read more.
This study describes the preparation and use of a dental amalgam electrode for the voltammetric determination of triazine-based pesticides ametryn, atrazine, and simazine in natural waters, using square wave voltammetry. The experimental and voltammetric parameters were previously optimized, and analytical curves were constructed to calculate analytical parameters. The detection limits presented values that were lower than the maximum limits of residues permitted in natural water by the Brazilian Environmental Agency, 100 µg L−1 (100 ppb), and around the values obtained using other electrodic surfaces or high-performance liquid chromatography, traditionally used in triazine levels determination. Furthermore, the recovery percentages in pure electrolyte and natural waters were around 100%, demonstrating that the methodology proposed is suitable for determining triazines contamination in natural water samples, based on an environmentally friendly procedure. Full article
(This article belongs to the Section Electroanalysis)
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