Field Of Analytical Chemistry Research Articles

Natural kapok fiber as a green and efficient adsorbent for in-syringe solid-phase extraction in the determination of antidepressants in biofluids

Effective antidepressant monitoring is crucial for safe treatment, with liquid chromatography being the primary detection method. Due to the complexity of biofluids, meticulous sample preparation is vital to remove interferences and concentrate analytes. In this study, a novel solid-phase extraction method utilizing unprocessed kapok fiber (KF) as an eco-friendly and efficient sorbent, ingeniously incorporated within an in-syringe device for the extraction of antidepressants from biofluids was introduced. The extraction process displayed several advantages, including simplicity and rapidity (less than 3 min with minimal manual intervention), as well as the potential for automation, which represents significant advancements in sample preparation techniques. The method demonstrated excellent analytical performance when coupled with high-performance liquid chromatography-ultraviolet detection, achieving good linearity (R2 ≥ 0.991), excellent relative recovery (92.6–107.5 %), high precision in intraday and interday analyses (RSDs within 0.8–6.0 % and 1.2–7.9 %, respectively), and good sensitivity with limits of quantification between 5–10 ng/mL. Notably, given the use of a renewable and biodegradable material with KF, and a low-toxicity desorption solvent with ethanol, the developed method stands out for its environmental sustainability, aligning with green analytical chemistry principles. Its application to real biological samples validates its efficacy as a rapid and reliable tool for clinical and forensic monitoring of antidepressants. Moreover, the low cost of this method facilitated by the economical nature of KF and the reusability of syringes further enhances its practicability. This study presents a unique approach by employing natural and renewable KF as adsorbents, thereby eliminating the need for complex material synthesis and making a pioneering contribution to the field of analytical chemistry for drug analysis in complex matrices.

Extrapolation of cytotoxic masked effects in planar in vitro assays.

The masking of specific effects in in vitro assays by cytotoxicity is a commonly known phenomenon. This may result in a partial or complete loss of effect signals. For common in vitro assays, approaches for identifying and quantifying cytotoxic masking are partly available. However, a quantification of cytotoxicity-affected signals is not possible. As an alternative, planar bioassays that combine high-performance thin layer chromatography with in vitro assays, such as the planar yeast estrogen screen (p-YES), might allow for a quantification of cytotoxically affected signals. Affected signals form a typical ring structure with a supressed or completely lacking centre that results in a double peak chromatogram. This study investigates whether these double peaks can be used for fitting a peak function to extrapolate the theoretical, unaffected signals. The precision of the modelling was evaluated for four individual peak functions, using 42 ideal, undistorted peaks from estrogenic model compounds in the p-YES. ModelledED50-values from bisphenol A (BPA) experiments with cytotoxically disturbed signals were 13 times higher than for the apparent data without compensation for cytotoxicity (320 ± 63 ng versus 24 ± 17ng). This finding has a high relevance for the modelling of mixture effects according to concentration addition that requires unaffected, complete dose-response relationships. Finally, we applied the approach to results of a p-YES assay on leachate samples of an elastomer material used in water engineering. In summary, the fitting approach enables the quantitative evaluation of cytotoxically affected signals in planar in vitro assays and alsohas applications for other fields of chemical analysis like distorted chromatography signals.

Nanocomposite microbeads made of recycled polylactic acid for the magnetic solid phase extraction of xenobiotics from human urine

Nanocomposite microbeads (average diameter = 10–100 µm) were prepared by a microemulsion-solidification method and applied to the magnetic solid-phase extraction (m-SPE) of fourteen analytes, among pesticides, drugs, and hormones, from human urine samples. The microbeads, perfectly spherical in shape to maximize the surface contact with the analytes, were composed of magnetic nanoparticles dispersed in a polylactic acid (PLA) solid bulk, decorated with multi-walled carbon nanotubes (mPLA@MWCNTs). In particular, PLA was recovered from filters of smoked electronic cigarettes after an adequate cleaning protocol. A complete morphological characterization of the microbeads was performed via Fourier-transform infrared (FTIR) spectroscopy, UV–Vis spectroscopy, thermogravimetric and differential scanning calorimetry analysis (TGA and DSC), scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The recovery study of the m-SPE procedure showed yields ≥ 64%, with the exception of 4-chloro-2-methylphenol (57%) at the lowest spike level (3 µg L−1). The method was validated according to the main FDA guidelines for the validation of bioanalytical methods. Using liquid chromatography-tandem mass spectrometry, precision and accuracy were below 11% and 15%, respectively, and detection limits of 0.1–1.8 µg L−1. Linearity was studied in the range of interest 1–15 µg L−1 with determination coefficients greater than 0.99. In light of the obtained results, the nanocomposite microbeads have proved to be a valid and sustainable alternative to traditional sorbents, offering good analytical standards and being synthetized from recycled plastic material. One of the main objectives of the current work is to provide an innovative and optimized procedure for the recycling of a plastic waste, to obtain a regular and reliable microstructure, whose application is here presented in the field of analytical chemistry. The simplicity and greenness of the method endows the procedure with a versatile applicability in different research and industrial fields.Graphical

Knoevenagel reaction promoted by functional ionic liquids with primary and tertiary amines

ABSTRACT Functional ionic liquids have been widely used in the fields of synthetic chemistry, analytical chemistry, electrochemistry and material chemistry owing to their excellent properties such as easy structure modification and adjustable properties. In this work, a series of basic functionalized ionic liquids were prepared from 1, 4-diazabicyclo [2.2.2] octane (DABCO) or hexamethylenetetramine (HMTA) with various halogenated hydrocarbons, then these functional ionic liquids and water were used as solvent-catalyst system in the Knoevenagel reaction of various aldehydes with ethyl cyanoacetate or malononitrile, the influence of the structure of the ionic liquid and the content of water was investigated. The results showed that the composite solvent-catalyst system mixed by the functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo [2.2.2] octane bromide with water can effectively promote the Knoevenagel reaction and the alkalinity of amine and hydrogen bond play an important role. Aromatic aldehydes with electron-donating or electron-withdrawing groups can obtain the target product at an excellent yield (79-99%). It is worth noting that the polycyclic aromatic aldehydes with high steric hindrance, 86%-95% yields of the object products were also obtained after 15 h-25 h. Furthermore, the catalyst could be reused for 6 times without any loss in its catalytic activity. The composite solvent-catalyst system mixed by the Functional ionic liquid N-(3-aminopropyl)-1,4-diazabicyclo[2.2.2]octane bromide with water can effectively promote the Knoevenagel reaction, even for the electron-rich aromatic aldehydes with poor reactivity, high yields of the target products and fast reaction rate were also obtained at room temperature.

Developing Green Sorbents Derived from Natural Materials for Microextraction and Determination of Emerging Contaminants

Microextraction technologies emerged as an attractive and eco-efficient alternative in sample preparation with the advent of solid-phase microextraction (SPME).1 The sensitivity and precision of methodologies based on microextraction are improving due to the ease of preconcentration and automation capacity that they provide, respectively. Furthermore, the miniaturization and eco-efficiency have improved considerably by using less space and avoiding the use of toxic reagents and high volumes of organic solvents. From the 1990s until the present, SPME has continued to evolve, becoming commercially available for many chromatographic applications. Also in this period, stir bar sorptive extraction (SBSE) has become another commercially available alternative,2 with the extraction device offering a greater volume of sorbent phase compared to SPME. Simultaneously, other novel microextraction techniques have emerged that complement some of the drawbacks of SBSE.3 Among these microextraction techniques, rotating-disk sorptive extraction (RDSE) was proposed by our research group in 2009 and has been recently reviewed, considering all its advances and applications.4,5 The heart of all microextraction technologies is the nature of the sorbent phase. In the context of solid sorbents, they can be classified as synthetic or natural materials according to their origin (Figure 1). Typical examples of synthetic sorbents range from the most hydrophobic octadecyl (C18) to the ion exchange phases, most of them being commercially available. Sorbents of intermediate polarity (hydrophilic–lipophilic balance) and hydrophilic-like silica-based sorbents are also commercially available. In the specific case of emerging contaminants, the copolymer of divinylbenzene and N-vinylpyrrolidone (OasisTM HLB) has largely been used, considering that its hydrophilic–lipophilic balance allows various sorption interactions with emerging contaminants. Among them, hydrophobic interactions occur through -stacking and polar interactions occur via hydrogen bonding. The hydrophilic–lipophilic balance typical of OasisTM HLB has encouraged its use in RDSE as a sorbent in multiresidue analysis.6,7 Although sorbents based on these commercial polymers are being used in different microextraction techniques, some trends are currently being claimed in the design of solid sorbents by considering new synthetic materials. In this context, micro- and nanomaterials have been tested, such as carbon nanotubes, graphene and fullerenes.8 Interactions via delocalized -electrons are especially important for molecules containing aromatic rings, as in the case of emerging contaminants. Other nonconventional materials9 that are being actively studied as synthetic sorbents are porous solids such as metal organic frameworks, covalent organic frameworks and layered double hydroxides. Together with these sorbent developments, the innovation in materials of natural origin, which can be recycled, is another parallel trend in analytical chemistry and is the central idea to be addressed in the current research of our team. As mentioned previously, a current challenge in analytical chemistry is to emphasize the use of eco-efficient or green analytical processes, positioning this characteristic at the same level as the sensitivity and selectivity of the measurement. Microextraction technology is green per se, given the minimization of the consumption of organic solvents in the sample preparation stage. However, an even higher level of analytical eco-efficiency (or greenness) is achieved when the sorbent phase used is of natural origin; in this way, the use of natural materials is in line with the change of the paradigm of typical production models (take–make–dispose) towards a circular model of waste reuse.10 Sorbents of natural origin can be classified according to their chemical composition as inorganic and organic sorbents. Clay is an example of an inorganic sorbent that plays an important role in the retention/mobility behavior of chemicals in the soil. Consequently, materials based on clay have been proposed as sorbents in different microextraction devices.11 Clays can also be modified to decrease their polarity for use in the sorption of hydrophobic analytes.11,12 Natural organic sorbents, also called biopolymeric sorbents, can be classified by their origin as natural polymers of plant origin (polysaccharides, proteins, polyesters), animal origin (polysaccharides, proteins, resins) and microbial origin (polysaccharides, polyesters, polyamides, polyanhydrides).13 All these materials prepared from natural biopolymers have been studied and proposed primarily in water treatment technologies; however, they could also be considered in the field of analytical chemistry as microextraction/extraction sorbents. The main novelty of this idea is that it is only recently, and in only a few cases, that these sorbents been used in microextraction technology, with wide future perspectives being expected.10,13 These natural materials can also be modified through known reactions of functionalization (selective oxidation, esterification, crosslinking, copolymerization, etc.). Such modifications reinforce the potential of the functional group and the number of active sites of the sorption material.14 In addition, modification of the natural materials can be achieved by pyrolysis to produce biochar. During the pyrolysis process, the components are thermally decomposed at different temperatures and times, expanding their porosity. Besides to increase the degree of aromatic condensation and aromaticity, typical functionalities present on the biochar surface include hydroxyl, carboxylic, lactone, amine and amide moieties, which are the key to its sorptive properties15 and the retention of pollutants of different natures. Similarly, from these natural materials, activated carbon can be generated at a significantly lower cost than from the same commercial substrate. To prepare activated carbon from these natural materials, two basic steps are required: pyrolysis of the raw material; and activation. Pyrolysis in the temperature range of 300–900 °C produces biochar with the required porosity associated with high carbon content. The activation step then provides a material with a higher surface area, generating additional porosity, and allows adjustment of the chemical surface to produce unique characteristics.16 During recent years, our research group has been contributing to this research field by designing new natural sorbent phases to be applied in the microextraction of emerging contaminants from wastewater and river water. Some examples of natural sorbent phases implemented in our laboratory are peanut shells,17 cork,18 avocado seed19 and chitosan.20 In various instances, these materials or their derivatives have shown comparative sorption behavior with commercial sorbents such as OasisTM HLB. By using these natural sorbents, emerging contaminants have been quantified in wastewater and river water samples from the metropolitan region of Chile.

UHPLC-MS/MS Technique: Applications in Analytical Chemistry

The ultra-high performance liquid chromatography-mass spectrometry/mass spectrometry (UHPLC-MS/MS) is becoming most advanced technique used for analysis of wide range of compounds in analytical chemistry. This technique has been effectively utilized for identifying and quantitatively determining substances in several pharmaceutical analysis fields. The UHPLC technique offers superior sensitivity, selectivity and peak shape in comparison to the conventional HPLC technique. The UHPLC coupled with various mass spectrometers gives accurate mass fragmentations which is ultimately helpful in structural identification and quantitative determination of compounds. The review provides brief introduction on development of UHPLC column packing materials and coupled mass detectors such as single quadrupole, triple quadrupole and time-of-flight mass. This review article also summarizes application of UHPLC-MS/MS technique in various fields of analytical chemistry.

Can the heptapeptide ASSIVSF of the β2-adrenoceptor recognize ephedrine and pseudoephedrine epimers in a complex system?

Epimer separation is crucial in the field of analytical chemistry, separation science, and the pharmaceutical industry. No reported methods could separate simultaneously epimers or even isomers and remove other unwanted, co-existing, interfering substances from complex systems like herbal extracts. Herein, we prepared a heptapeptide-modified stationary phase for the separation of 1R,2S-(-)-ephedrine [(-)-Ephe] and 1S,2S-(+)-pseudoephedrine [(+)-Pse] epimers from Ephedra sinica Stapf extract and blood samples. The heptapeptide stationary phase was comprehensively characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The separation efficiency of the heptapeptide column was compared with an affinity column packed with full-length β2-AR functionalized silica gel (β2-AR column). The binding affinity of the heptapeptide with (+)-Pse was 3-fold greater than that with (-)-Ephe. Their binding mechanisms were extensively characterized by chromatographic analysis, ultraviolet spectra, circular dichroism analysis, isothermal titration calorimetry, and molecule docking. An enhanced hydrogen bonding was clearly observed in the heptapeptide-(+)-Pse complex. Such results demonstrated that the heptapeptide can recognize (+)-Pse and (-)-Ephe epimers in a complex system. This work, we believe, was the first report to simultaneously separate epimers and remove non-specific interfering substances from complex samples. The method was potentially applicable to more challenging sample separation, such as chiral separation from complex systems.

New azo dyes for detection of metallic impurities

In the world of molecular sensing, the ability to detect and differentiate between various analyte is a crucial aspect of scientific exploration. In this study, two novel azo dyes Dye-1 and Dye-2 that exhibit distinct sensing capabilities were synthesized and characterized. Dye-1 and Dye-2, each possess unique sensing capabilities. Dye-1 demonstrates an impressive affinity for the metal ion sensing and reveals differential colorimetric detection of metal ions based on the solvent system. Dye-2 on the other hand do not reveal significant color changes on addition of different metal ions, however it does reveal a selective and specific detection for dichromate (Cr2O72−) ions exclusively. The limit of detection (LOD) values obtained highlights the considerable sensitivity of Dye-1 and Dye-2 as a chemosensor. Finally, the utility of both the dyes for the detection of metallic impurities in real water samples has been demonstrated. The mechanism by which Dye-1 and Dye-2 binds to different metallic ions was also explored and studied through Density Functional Theory (DFT) computational modelling. This research contributes to the understanding of molecular sensing and offers potential applications in the field of analytical chemistry and environmental monitoring.

Integration of a facile sustainable resonance Rayleigh scattering switchable-based system for feasible determination of centrophenoxine, a nootropic and antioxidant agent; application to crude materials and dosage forms

The proposed research adheres to a certain methodology to ensure that the technique used for analyzing the centrophenoxine drug is sustainable and green. It is important to highlight that several tools that have been recently developed were utilized as potential indicators of environmental sustainability and applicability. The present research presents a novel and entirely innovative method utilizing ultrasensitive spectrofluorimetry for the detection of centrophenoxine (CPX) drug. The employed methodology in this study involved the utilization of one-step, one-pot, and direct spectrofluorimetric technique, which was found to be both efficient and environmentally sustainable in the validation and assessment of the drug. Simply, when CPX and erythrosine B reagent were combined in an acidic environment, the highly resonance Rayleigh scattering product was immediately produced. The sensitivity limits were observed to be within the range of 15–47 ng mL−1, whereas the linearity was assessed to be in the range of 50–2000 ng mL−1. The optimal settings for all modifiable parameters of the system were ascertained through an analysis of centrophenoxine-erythrosine B complexes. Moreover, the system demonstrated compliance with International Council for Harmonization (ICH) specifications without encountering any issues. The suggested process was then rated on different recent environmental safety measuring metrics to see how good it was for the environment. Fortunately, the WAC standards that combine ecological and functional elements utilizing the Green/Red/Blue (RGB 12) design also acclaimed the current analytical technique as a white one. Additionally, a new applicability evaluation tool (BAGI) was employed to estimate the practicability of the planned method in the analytical chemistry field.

Direct observation and elemental analysis of material nanoparticles in solution using scanning electron-assisted dielectric microscopy and EDS

High-resolution observation and elemental analysis of various particles in solution are important in the fields of materials, analytical chemistry, and industrial applications. Analysis of slurries of raw materials is essential for the development of highly functional materials. Recently, we have developed an SEM-based scanning electron assisted dielectric microscope (SE-ADM), which can directly observe biological samples and organic materials in aqueous solutions. Here, we have developed an SE-ADM system with the addition of energy-dispersive x-ray spectrometry that enables direct observation and elemental analysis of nanoparticles in solution. Using this system, we were able to directly observe and conduct elemental analysis of ceramic slurries and to clarify the dispersion state of alumina particles in solution, the distribution of binder, and the bonding state of silica and magnesium particles. Furthermore, our system can be applied to diverse liquid samples across a broad range of scientific and industrial fields, for example, nanotubes, organic specimens, batteries, and catalytic materials.

Analytical Biology: An Emerging Discipline for the Future

The field of analytical chemistry is well established. It’s time to develop the field of analytical biology—an emerging discipline that blends various research fields to provide a holistic view of biological phenomena.

Analisis Dan Perancangan Website SMKN 13 Bandung

Information and communication technology plays an important role in supporting and increasing efficiency in managing daily activities, as well as enabling work to be done from anywhere. 13 Bandung Vocational High School is a secondary level school in the city of Bandung which has competency expertise in the fields of Chemical Analysis, Computer Network Engineering and Software Engineering. 13 Bandung Vocational High School needs a website as a school media for conveying information about school activities and as a media for promoting the school to the general public so that people know more about SMKN 13 Bandung. The system development method uses the prototype development method. Prototyping is the creation of an accurate testing system. Through a prototype, managers can get an overview and ideas regarding the application design requirements. The results of this research are to provide the results of the analysis and provide the results of designing the 13 Bandung Vocational High School website with the hope that this website design can be used for the implementation process of creating the 13 Bandung Vocational High School website

LC-ESI-HRMS — lipidomics of phospholipids

Lipids are a diverse class of molecules involved in many biological functions including cell signaling or cell membrane assembly. Owing to this relevance, LC–MS/MS-based lipidomics emerged as a major field in modern analytical chemistry. Here, we thoroughly characterized the influence of MS and LC settings — of a Q Exactive HF operated in Full MS/data-dependent MS2 TOP N acquisition mode — in order to optimize the semi-quantification of polar lipids. Optimization of MS-source settings improved the signal intensity by factor 3 compared to default settings. Polar lipids were separated on an ACQUITY Premier CSH C18 reversed-phase column (100 × 2.1 mm, 1.7 µm, 130 Å) during an elution window of 28 min, leading to a sufficient number of both data points across the chromatographic peaks, as well as MS2 spectra. Analysis was carried out in positive and negative ionization mode enabling the detection of a broader spectrum of lipids and to support the structural characterization of lipids. Optimal sample preparation of biological samples was achieved by liquid–liquid extraction using MeOH/MTBE resulting in an excellent extraction recovery > 85% with an intra-day and inter-day variability < 15%. The optimized method was applied on the investigation of changes in the phospholipid pattern in plasma from human subjects supplemented with n3-PUFA (20:5 and 22:6). The strongest increase was observed for lipids bearing 20:5, while 22:4 bearing lipids were lowered. Specifically, LPC 20:5_0:0 and PC 16:0_20:5 were found to be strongest elevated, while PE 18:0_22:4 and PC 18:2_18:2 were decreased by n3-PUFA supplementation. These results were confirmed by targeted LC–MS/MS using commercially available phospholipids as standards.Graphical abstract

A signal polarity conversion photoelectrochemical immunosensor for neuron-specific enolase detection based on MgIn2S4-sensitized CsPbBr3.

Aphotoelectrochemical (PEC) immunosensor was designed based on MgIn2S4-decorated inorganic halide perovskite CsPbBr3 combined with the signal polarity conversion strategy for neuron-specific enolase (NSE) detection. CsPbBr3 was applied as the basic photoactive material owing to its excellent optical and electronic properties, which provide a good PEC performance for sensor construction. In order to improve the stability of this perovskite, the three-dimensional flower-like MgIn2S4 with a desirable direct band gap was applied to enhance the PEC response. Also, the excellent structure of MgIn2S4 provides large surface-active sites for CsPbBr3 loaded. For enhancing the detection sensitivity of PEC immunosensor, p-type CuInS2 was used as a signal probe which fixed on detection antibody (Ab2). When the target NSE was present, the photogenerated electrons produced by CuInS2 were transferred to the test solution, and the polarity of PEC signal changes. Based on the above photosensitive materials and signal conversion strategy, the proposed PEC immunosensor showed favorable detection performance, and the lineardetection range is 0.0001 ~ 100ng/mL with a 38fg/mL of detection limit. The proposed strategy improved the adhibition of CsPbBr3 in the analytical chemistry field as well as provided a reference method for other protein detections.

Analytical Chemistry is like the Fruit of an Apple Tree

Analytical chemistry is deeply rooted in Europe. It started with the work of Liebig and Fresenius, among others. Then Kirchhoff, as father of spectroscopy, contributed to the development of the modern instrumental analysis techniques flourishing today. As soon as I started learning analytical chemistry at university, I fell in love with it. At that time, I could not explain why I wanted to become an analytical chemist. Having gained experience teaching and performing research in analytical chemistry, I know now that I am attracted to it because this branch of chemistry is what an apple means to an apple tree - the fruit of a myriad of results in fundamental research in chemistry, always offering solutions to real life problems. I always wanted to become an analyst and to work at the analytical chemistry department where I studied. One year ago, my life drastically changed at the institute when I was invited to apply to lead the analytical chemistry department where I have been working since 2007. I must admit that I had mixed feelings in the beginning. First of all, I was honored that my colleagues in the department fully expressed their support. At the same time, I was confused and scared. I felt that I am not the right person to lead a department with a history of almost 120 years, that I had no clear vision of what could I do for my colleagues and for the students choosing our department. However, I wanted to express my gratitude to my colleagues for their trust in me. In my application, I advocated to maintain the high-quality teaching of analytical chemistry at the department and offered to implement challenge-based learning for students choosing our department. In past years, I felt that the raison d'être of analytical chemistry departments as single entities would soon end. My colleagues working in other fields such as biology, geography and geology, pharmacy and medicine, all purchased instrumental analytical equipment and started performing research by themselves. Recently, analytical chemistry departments underwent important organizational and structural changes. Some of them disappeared, others incorporated into their name environmental chemistry, food chemistry, or biochemistry. Recent advances in instrumental analysis create the impression that conducting chemical analysis is an easy task that no longer requires the expertise of chemists devoted to this branch of chemistry. However, there is still a lot of work to do, especially in the field of organic analytical chemistry. Thanks to innovations in mass spectrometry and related techniques, infrared spectroscopy, miniaturization (lab-on-chips) and sensors, ultra trace analysis, green methodologies, and elemental speciation, analytical chemistry is experiencing a second Golden Era. In last year alone, I was surprised by the ever-increasing number of chemistry bachelor and major students knocking on my door asking me to provide them with analytical chemistry-related research topics. That led me to contact faculty working at the other institutes offering cooperation with the arsenal of our instruments to widen the research topic choices in our department, advocating that we should unite and complement our efforts to create synergies. Surprisingly, the response of those colleagues was very positive. In one year, I could almost double the number of research topics for diploma work in our department. This is something that makes me happy and optimistic. I am confident that the development of analytical methods together with proper sampling and sample preparation are still important and crucial steps to produce high quality and reliable results. Moreover, participation of analytical chemists in these tasks is indispensable. The recent success of the Brazilian Journal of Analytical Chemistry achieving an impact factor of 0.7 makes me also think that analytical method development has still a bright future ahead. Long live Analytical Chemistry! Long live Brazilian Journal of Analytical Chemistry!

BrJAC 2023 – Growing and Building Bridges

In 2010, in the first BrJAC Editorial, Kubota emphasized: “We are launching BrJAC – Brazilian Journal of Analytical Chemistry to open a discussion about the real role of the Analytical Chemistry for the development of the country and bring the improvement of the life quality. BrJAC is an Analytical Chemistry journal whose goal is to debate, discuss, show trends, and needs with opinion editorials and interviews with renowned investigators, besides publishing scientific papers from the academic and industry, fulfilling the idealistic purpose of a group of people to achieve actual academic industrial integration towards innovation and technical-scientific development.”1 In this same issue I had the opportunity to write a Point of View and I stated: “The launching of Brazilian Journal of Analytical Chemistry (BrJAC) is a milestone with full potential to expand the flow of knowledge. The integration of academy and industry is a must and BrJAC will certainly play a major role in putting them in contact.”2 After a relatively short span of time (just 13 years!), it is amazing to think about how much was accomplished. As announced since the beginning, each issue has a great combination of reviews, scientific articles, points of view, letters, sponsors’ reports, releases, news, and interviews. This list of contents is part of the identity of BrJAC and each section plays a special role. Of course, articles are the core of any scientific journal, but to create and consolidate bridges we need to integrate academia and industry, so different forms of communication are in the BrJAC fingerprint. And how could we move ahead without listening to well-known analytical chemists? Fortunately, since its beginning, BrJAC has opened its pages for interviews. We began in 2010 with Prof. Carol Hollingworth Collins (Institute of Chemistry, State University of Campinas)3 and travelled all the way to Dr. Joanna Szpunar (National Research Council of France, CNRS) in the last issue.4 I have no doubt that important landmarks of the history of analytical chemistry in Brazil were revealed in a colloquial atmosphere in these interviews. Recently, Marco Arruda, the Editor-in-Chief, posted a letter on the journal website entitled, “From dream to reality”5 and invited us to celebrate the indexation of BrJAC by Clarivate and its starting impact factor of 0.7. Certainly, the Brazilian community in analytical chemistry has a lot to celebrate and it is amazing to reach this point when we think about the challenges along the 13-year road (and please keep counting!). In his letter, Marco Arruda mentioned challenges related to logistics, economy, ethics, and scientific quality. Surely, these are critical aspects. We live in an increasingly complex society full of opportunities and challenges. I am not thinking about political turmoil, social inequalities, and climate crisis. You know how big these challenges are. However, I would like to mention two other major challenges that we have coped with (or we are coping with) during the lifetime of BrJAC. One critical moment was the years of the COVID-19 pandemic and how they affected our way of life. We are still trying to understand all that has happened and how we have changed. The economy was affected. Work routines were affected. Families and friends were affected. Institutions were affected. Once again, we have practiced important human values, such as solidarity, fraternity, and the shared goal to move ahead as a society. Once again, science has rescued us. Another major influence when thinking about complexity and the scientific literature comes from predatory journals. The routinization of research and its diffusion are landmarks for the evolution of science, technology, and innovation. Scientific journals are important foundations for dissemination of research. Notwithstanding, nowadays we are coping with paper mills that produce fake papers just for profit. Recently, we are starting to face the dangerous combination of paper mills and artificial intelligence to produce polluted science. Despite some clouds on the horizon, it is great to see how the BrJAC community was able to grow during these hard times. We have achievements to celebrate and BrJAC is a great one. Recently, The Analytical Scientist asked researchers about the biggest challenge facing the analytical chemistry field.6 I would like to highlight the comments expressed by Prof. Robert Graham Cooks: “A lack of appreciation of the intricacies of analytical science by other disciplines (especially chemists) who see it as little more than an exercise in measurement using commercial instrumentation. Like modern day pharaohs, the organic synthetic chemist commands – “measure it!” – without pausing to recognize the ingenuity that went into the slaves’ work of conceiving the method, building the instrumentation, and achieving useful performance criteria. The “measure it” request at the end of that multi-year process is often a simple application, but the process that allows it is a unique combination of new scientific insights and skillful technology.”. And Richard Zare: “Simply put, gaining more respect for analytical science’s importance to understanding nature.”. I do think BrJAC is part of the multifarious mechanism to bring better understanding and more respect to analytical sciences. Let us keep our focus and strength. As always, “time keeps flowing like a river” (Time, The Alan Parsons Project).

CRISPR/Cas12a triggered SERS and naked eye dual-mode biosensor for ultrasensitive and on-site detection of nucleic acid via cascade signal amplification

Highly sensitive and on-site detection of nucleic acids has always been a critical issue in the field of analytical chemistry. Surface-enhanced Raman scattering (SERS)-based biosensing exhibits huge potential in nucleic acid detection, while the applicability is restricted in trace nucleic acid screening due to the lack of appropriate signal recognition, transducing and amplification technologies. Inspired by the specific recognition of CRISPR/Cas12a and the improved sensitivity through cascade signal amplification, we innovatively proposed a CRISPR/Cas12a triggered SERS and naked eye dual-mode biosensor for ultrasensitive and on-site detection of nucleic acid via cascade signal amplification. Upon the target DNA recognition, the activated CRISPR/Cas12a indiscriminately cleaved substrate ssDNA, leading to the failure of toehold-mediated DNA-strand displacement reaction (TSDR), and triggering hybridization chain reaction (HCR) to assemble numerous G-quadruplex/hemin DNAzyme (GQH DNAzyme) for cascade signal amplification. The generated GQH DNAzyme catalyzed the oxidation of l-cysteine to cystine, perturbing the aggregation of 4-NTP@AuNPs, resulting in significant Raman signal change. On the other hand, GQH DNAzyme catalyzed the oxidation of 2,2′-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), leading to obvious color change to realize portable naked-eye detection. Through this strategy, target nucleic acid concentration was tactfully transformed into sensitive Raman and portable visualization signals, and the limit of detection were as low as 34.9 aM and 1 pM, respectively. Then, this biosensor was successfully applied to meat adulteration detection, which showed superb selectivity, sensitivity and applicability for on-site detection of trace nucleic acid in complicated food matrix.

Paper-based sensors: affordable, versatile, and emerging analyte detection platforms.

Paper-based sensors, often referred to as paper-based analytical devices (PADs), stand as a transformative technology in the field of analytical chemistry. They offer an affordable, versatile, and accessible solution for diverse analyte detection. These sensors harness the unique properties of paper substrates to provide a cost-effective and adaptable platform for rapid analyte detection, spanning chemical species, biomolecules, and pathogens. This review highlights the key attributes that make paper-based sensors an attractive choice for analyte detection. PADs demonstrate their versatility by accommodating a wide range of analytes, from ions and gases to proteins, nucleic acids, and more, with customizable designs for specific applications. Their user-friendly operation and minimal infrastructure requirements suit point-of-care diagnostics, environmental monitoring, food safety, and more. This review also explores various fabrication methods such as inkjet printing, wax printing, screen printing, dip coating, and photolithography. Incorporating nanomaterials and biorecognition elements promises even more sophisticated and sensitive applications.

Facile green synthesis of wasted hop-based zinc oxide nanozymes as peroxidase-like catalysts for colorimetric analysis.

Hops are a common ingredient in beer production, and a considerable quantity of hops is usually discarded as a waste material once the brewing process is completed. Transforming this waste material into valuable nanomaterials offers a sustainable approach that has the potential to significantly mitigate environmental impact. Herein, a facile and green protocol for the production of zinc oxide nanozymes (ZnO NZs) using wasted hop extract (WHE) as a natural precursor was demonstrated. The process involved a hydrothermal synthesis method followed by a calcination step to form the final ZnO NZs. The results revealed that lupulon, the main β-acid in hops, particularly the phenolic hydroxy group, is primarily responsible for the biosynthesis of ZnO NZs. The WHE-ZnO NZs exhibited exceptional peroxidase-like (POD-like) activity and served as effective catalysts for the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). Analysis of the catalytic mechanism revealed that the POD-like activity of these WHE-ZnO NZs originated from their ability to expedite the transfer of electrons between TMB and H2O2, resulting in the enzymatic kinetics following the standard Michaelis-Menten mechanism. Furthermore, we developed a straightforward and user-friendly colorimetric technique for detecting both H2O2 and glucose. By utilizing the WHE-ZnO NZs as POD-like catalysts, we achieved a linear detection range of 1-1000 μM and a limit of detection of 0.24 μM (S/N = 3) for H2O2 detection and a linear range of 0-100 mM and a detection limit of 16.73 μM (S/N = 3) for glucose detection. These results highlighted the potential applications of our waste-to-resource approach for nanozyme synthesis in the field of analytical chemistry.

Ion Transport in Intelligent Nanochannels: A Comparative Analysis of the Role of Electric Field.

This research delves into investigating ion transport behavior within nanochannels, enhanced through modification with a negatively charged polyelectrolyte layer (PEL), aimed at achieving superior control. The study examines two types of electric fields─direct current and alternating current with square, sinusoidal, triangular, and sawtooth waveforms─to understand their impact on ion transport. Furthermore, the study compares symmetric (cylindrical) and asymmetric (conical) nanochannel geometries to assess the influence of overlapping electrical double layers (EDLs) in generating specific electrokinetic behaviors such as ionic current rectification (ICR) and ion selectivity. The research employs the finite element method to solve the coupled Poisson-Nernst-Planck and Navier-Stokes equations under unsteady-state conditions. By considering factors such as electrolyte concentration, soft layer charge density, and electric field type, the study evaluates ion transport performance in charged nanochannels, investigating effects on concentration polarization, electroosmotic flow (EOF), ion current, rectification, and ion selectivity. Notably, the study accounts for ion partitioning between the PEL and electrolyte to simulate real conditions. Findings reveal that conical nanochannels, due to improved EDL overlap, significantly enhance ion transport and related characteristics compared to cylindrical ones. For instance, under ηε = ηD = 0.8, ημ = 2, C0 = 20 mM, and NPEL/NA = 80 mol m-3 conditions, the average EOF for conical and cylindrical geometries is 0.1 and 0.008 m/s, respectively. Additionally, the study explores ion selectivity and rectification based on the electric field type, unveiling the potential of nanochannels as ion gates or diodes. In cylindrical nanochannels, the ICR remains at unity, with lower ion selectivity across waveforms compared to conical channels. Furthermore, rectification and ion selectivity trends are identified as Rf,square > Rf,DC > Rf,triangular > Rf,sinusoidal > Rf,sawtooth and Ssawtooth > Ssinusoidal > Striangular > SDC > Ssquare for conical nanochannels. Our study of ion transport control in nanochannels, guided by tailored electric fields and unique geometries, offers versatile applications in the field of Analytical Chemistry. This includes enhanced sample separation, controlled drug delivery, optimized pharmaceutical analysis, and the development of advanced biosensing technologies for precise chemical analysis and detection. These applications highlight the diverse analytical contributions of our methodology, providing innovative solutions to challenges in chemical analysis and biosensing.