Absorption Changes Research Articles

Study of Electrochromic Properties of PEDOT:PSS for Tunable Filter Optics with Lithium Salt Electrolyte

Nowadays, conductive polymers based on poly(3,4-ethylenedioxythiophene), poly(styrene sulfonic acid), or PEDOT:PSS, have been employed as a flexible and transparent coating in various significant electronic applications. With the demand for electrochromic properties, such as in electronic displays, further research into its electrooptic properties is required, especially the systematic understanding to obtain the optimized switching. Our research investigates the electrooptic properties of the PEDOT:PSS film, particularly the refractive index changing under various applied biases. The electrochromic device is prepared in a simple fashion, and the electroactive layer of PEDOT:PSS thickness is defined via spin-coating between two indium tin oxide (ITO) substrates. To increase the switching properties of PEDOT:PSS, lithium perchlorate (LiClO4) was prepared in acetonitrile, as the electrolyte in varied concentrations of 1.195 M, 1.5 M, and 2.0 M, respectively. A potential voltage of -4.0 V to 0.0 V is utilized to study the device's electrochromic properties with the step 5 mV/s continuously. Finally, the optical properties are characterized using the spectroscopy method based on real-time measurement of the transmission spectrum and transmission matrix calculations. The change in visible light absorption, transmission, and film color is recorded under a switching cycle that shows consistent behavior. This allows the further utilization of such a hybrid structure for possible tunable filter applications. Keywords: Electrochromic, PEDOT:PSS, Optical, Lithium salt, Electrolyte

Plant nutrient stoichiometry appears out of sync from soil: Increasing influences of changing climate on the grassland in inner Mongolia, China

Extremes in weather episodes seem to be the new normal. We need to better understand how changing climatic conditions alter plant growth in grasslands, especially macro nutrient uptake and stoichiometry. However, few studies have examined how warmer/colder or wetter/drier climates influence the nutrient coupling between plants and soils at the ecosystem level. Here, we investigated the changes in carbon (C), nitrogen (N), and phosphorus (P) concentrations and their stoichiometric ratios in plants and soils from 65 grassland sites along a geographic gradient in northern China. Results showed that soil C, N and P were negatively correlated with temperature and aridity. Plant N was positively correlated with temperature and aridity, but plant P was negatively correlated with temperature and aridity. Plant C had no significant relationship with either aridity or temperature. Both temperature and aridity were positively correlated with C:N, but negatively correlated with C:P and N:P in soils. The ratio of plant C:N was negatively correlated with aridity, while plant C:P was positively correlated with temperature. Plant N:P was positively correlated with temperature and aridity. Our findings imply that the often-found positive relationships between plant and soil nutrients at one site might not apply to a broad geographic scale with varying climatic conditions, likely because of the “dilution effect” and disparate plant nutrient utilization strategies. It is conceivable that rapid climate shifts and the resulting changes in element availability, turnover rates, absorption, and use efficiency might cause desynchrony of C, N, and P cycles between plants and soils.

Unraveling the Diagnostic Implications of Elevated Prealbumin Levels in Lithium-Induced Hypothyroidism: A Case Report

Prealbumin, a multifunctional protein synthesized primarily in the liver, serves as a critical biomarker in clinical practice, offering insights into nutritional status and prognostic outcomes. While its precise physiological role remains incompletely understood, prealbumin is known to facilitate hormone transport, particularly of thyroxine, and contribute to neuroprotection. Clinically, prealbumin levels are sensitive indicators of recent changes in protein intake and absorption, making them invaluable in guiding therapeutic interventions. Alterations in prealbumin levels have been associated with various medical conditions, including chronic kidney disease, liver disease, and cancer, emphasizing its prognostic significance across diverse clinical contexts. we report a case of a 42-year-old male with bipolar disorder managed on lithium therapy, presenting with depressive symptoms and unexpected hyperprealbuminemia. Subsequent investigation revealed primary hypothyroidism secondary to lithium intoxication, highlighting the intricate relationship between lithium therapy, prealbumin levels, and thyroid dysfunction. We discuss the mechanisms and clinical implications of lithium-induced hypothyroidism, emphasizing the importance of considering thyroid function in patients with elevated prealbumin levels. This case underscores the necessity for vigilant monitoring and timely intervention to optimize patient outcomes in cases of lithium-induced thyroid dysfunction. Continued research is crucial for elucidating the complex interactions between prealbumin, lithium therapy, and thyroid function, enhancing our understanding and management of these metabolic disturbances.

Dual-Function Wearable Hydrogel Optical Fiber for Monitoring Posture and Sweat pH.

In recent years, wearable devices have been widely used for human health monitoring. Such monitoring predominantly relies on the principles of optics and electronics. However, electronic detection is susceptible to electromagnetic interference, and traditional optical fiber detection is limited in functionality and unable to simultaneously detect both physical and chemical signals. Hence, a wearable, embedded asymmetric color-blocked optical fiber sensor based on a hydrogel has been developed. Its sensing principle is grounded in the total internal reflection within the optical fiber. The method for posture sensing involves changes in the light path due to fiber bending with color blocks providing wavelength-selective modulation by absorption changes. Sweat pH sensing is facilitated by variations in fluorescence intensity triggered by sweat-induced conformational changes in Rhodamine B. With just one fiber, it achieves both physical and chemical signal detection. Fabricated using a molding technique, this fiber boasts excellent biocompatibility and can accurately discern single and multiple bending points, with a recognition range of 0-90° for a single segment, a detection limit of 0.02 mm-1 and a sweat pH sensing linear regression R2 of 0.993, alongside great light propagation properties (-0.6 dB·cm-1). With its extensive capabilities, it holds promise for applications in medical monitoring.

Nanocellulose-based cobalt(II) coordinated malonic acid hybrid aerogels exhibiting reversible thermochromism and moisture sensor properties

The emergence of sustainable polymers and technologies has led to the development of innovative materials with minimal carbon emissions which find extensive applications in wearable electronics, biomedical sensors, and Internet of Things (IoT)-based monitoring systems. Nanocellulose which can be generated from abundant biomass materials has been widely recognized as a sustainable alternative for a diverse range of applications due to its remarkable properties and eco-friendly nature. By making use of the unique and easily accessible coordination transformation property of Co(II) ions and associated visible light absorption changes, we report a novel Co(II) cation-incorporated nanocellulose/malonic acid hybrid aerogel material that exhibits reversible thermochromism induced by thermal stimulus in the presence of atmospheric moisture. This effect is accentuated by the highly porous nature of the nanocellulose aerogel material we have developed. Besides the reversible thermochromic property which Co(II) ions exhibit, the metal ions act as very efficient reinforcing units contributing significantly to the structural stability and rigidity of the hierarchical aerogels by coordinative cross-linking through carboxylate moieties present in the TEMPO-oxidized cellulose nanofibers (TCNF) and additionally adding malonic acid to provide sufficient COO− for cross-linking. Thorough characterization and detailed investigation of as-prepared hybrid aerogels was conducted to evaluate their overall properties including reversible thermochromism and moisture sensor behaviour. Further, an Android mobile-based application was developed to demonstrate the real-world application of the aerogels for atmospheric humidity sensing.

Study of the Pectinase Production from Soursop and Cherimoya Pulp for Agro-Industrial Waste Reduction in Colombia

Pectic enzymes are an eco-friendly alternative to improve extraction processes for the food industry. The objective of the research was to obtain pectinase from the pulp of soursop (Annona muricata L.) and cherimoya (Annona cherimola L.), as an alternative to reduce agro-industrial waste in Colombia; involving the study of the factors influencing the protein content of the enzymes extracted from different stages and types of fruits, the conditions for enzymatic activity, and the potential application in the food industry, particularly in extraction processes and juice clarification. A factorial design 23, spectrometric and potentiometric techniques evidenced that the protein content depends on factors such as fruit stage (suitable “s” and unsuitable “u” fruits for consumption) and fruit type (soursop and cherimoya). The higher protein content was obtained by the precipitation method in comparison to ion exchange chromatography. Cherimoya fruit presented a higher protein content of 326 ± 26 mg by precipitation, however, the soursop samples evidenced higher enzymatic activity, 2.2 ± 0.1 U/mL. The pectinase obtained was an acidic enzyme of type pectin methylesterase with an enzymatic activity of 27.0 ± 0.9 U/mL, under the optimal conditions of pH 4 and temperature of 40 °C. The application in blackberry juice evidenced a decrease in the absorbance and pH changes. From the current research, the pulp of soursop and cherimoya was proven as a cheap source to obtain pectinase with enzymatic activity for juice clarification, and this process is an alternative to reduce the negative impact on the environment and an economical source for the local producers.

Investigations on temperature dependent properties of spray deposited tin oxide thin films

The present study reported the temperature dependent properties of tin oxide (SnO2) thin films deposited by using conventional, cost effective and non-vacuum-based spray pyrolysis technique (SPT). The as deposited films were characterized by various characterization techniques such as X ray diffraction (XRD), UV-Vis spectroscopy and Scanning electron microscopy (SEM) to study their structural, optical and morphological properties respectively. XRD analysis revealed tetragonal rutile crystal structure of SnO2 with preferred orientation along (200) plane. The refinement of XRD data was also carried out by Rietveld refinement to obtain the fitting parameters, crystallite size and lattice parameters. UV-Vis study showed considerable change in optical absorbance and transmittance with change in substrate temperature. Effect of substrate temperature on film thickness, refractive index and band gap energy were determined by Swanepoel method and by Tauc’s plot respectively. The Urbach energy was also calculated and were correlated to the defects in SnO2 films. SEM micrograph showed the transformation from granules to nanospheres as a function of substrate temperature. Electrical properties were determined by Hall effect measurements which gives carrier concentration, electrical resistivity and mobility in the order of 1019-1020 /cm3, 10−2-10−3 Ω.cm and 4–23 cm2/Vs respectively.

Colorimetric array sensor based on bimetallic nitrogen-doped carbon-based nanozyme material to detect multiple antioxidants.

Copper-cobalt bimetallic nitrogen-doped carbon-based nanoenzymatic materials (CuCo@NC) were synthesized using a one-step pyrolysis process. A three-channel colorimetric sensor array was constructed for the detection of seven antioxidants, including cysteine (Cys), uric acid (UA), tea polyphenols (TP), lysine (Lys), ascorbic acid (AA), glutathione (GSH), and dopamine (DA). CuCo@NC with peroxidase activity was used to catalyze the oxidation of TMB by H2O2 at three different ratios of metal sites. The ability of various antioxidants to reduce the oxidation products of TMB (ox TMB) varied, leading to distinct absorbance changes. Linear discriminant analysis (LDA) results showed that the sensor array was capable of detecting seven antioxidants in buffer and serum samples. It could successfully discriminate antioxidants with a minimum concentration of 10nM. Thus, multifunctional sensor arrays based on CuCo@NC bimetallic nanoenzymes not only offer a promising strategy for identifying various antioxidants but also expand their applications in medical diagnostics and environmental analysis of food.

A comprehensive research on γ-ray and particle radiation interaction parameters of Cerium doped heavy oxide inorganic scintillators

In this study, the interaction cross sections of heavy oxide scintillators, which have a very important place in high energy physics research, with photon and particle radiation were comparatively investigated. In this context, the interaction parameters of six different Ce-doped heavy oxide scintillators were obtained using updated software. The interactions of photons with energies between 1 keV and 100 GeV with scintillators were evaluated in the light of the results produced by the Phy-X/PSD software. In addition to the continuous energy range, calculations were also made on the photon energies emitted with the highest probability of emission from sources 241Am (59.54 keV), 133Ba (356 keV), 22Na (511 and 1280 keV), 137Cs (662 keV) and 152Eu (1460 keV). Additionally, evaluations of energy absorption build-up factors valid under broad beam conditions are also included in this study. Fast neutron absorption cross sections and changes in the range (R) values for heavy particle radiation in the range of 1 keV–20 MeV were also determined with SRIM and ESTAR software. All data obtained depending on energy are explained according to the mass percentages of Lu, Gd, Hf, Y, Al and O elements in the scintillators. The highest interaction cross section for photons was obtained in the Lu2Gd2SiO5 (Ce 0.3%) scintillator (HOS2). The interaction cross section of this scintillator was obtained as 3.115 and 0.042 cm2/g at 0.1 MeV and 10 MeV photon energies, respectively. On the other hand, the highest cross-sections of the fast neutrons were observed in the scintillator (HOS5) containing GdAlO3 (Ce 1.0%) as 0.148 cm−1. This difference in neutron radiation has been explained by calculating the individual attenuation abilities of the elements in the structures. It is hoped that the data obtained will guide researchers working on the detection of different types of radiation.

Design and Application of an In Situ Traceable Nitric OxideDonor for Promoting the Healing of Wound Infections.

Therapies for wound infections require medications with antibacterial and wound-healing functions. However, it remains a challenge to produce a single drug that can perform dual functions. Nitric oxide (NO), with its antibacterial and wound-healing activities, is an ideal solution to address this challenge. However, many controlled-release strategies for NO rely on external probes for tracing the release in situ, making it difficult to precisely assess the location and magnitude. To address this issue, this study describes a novel NO donor, DHU-NO1, capable of efficiently releasing NO under mild conditions (450nm illumination). Simultaneously, DHU-NO1 generates the fluorophore Azure B (AZB), which enables direct, non-consumptive tracing of the NO release by monitoring the fluorescence and absorption changes in AZB. Given that NO can be conveniently traced, the amount of released NO can be controlled during biological applications, thereby allowing both functions of NO to be performed. When applied to the affected area, DHU-NO1, illuminated by both a simple light-emitting diode (LED) light source and natural light, achieves significant antibacterial effects against wound infections and promotes wound healing in mice. This study offers a novel and effective approach for treating wound infections.

A ratiometric fluorescent probe for cysteine and glutathione differentiation and its application for cysteine detection in foods

Cysteine (Cys) and glutathione (GSH) are crucial biothiols implicated in cellular redox balance, necessitating accurate detection methods. Herein, we developed a novel fluorescent probe based on the fluorescent dye pyronin (PYR), capable of monitoring both Cys-and GSH using ratiometric fluorescence signals. The probe, named PYR-CG, where "C" stands for Cys-and "G" stands for GSH, demonstrates selective detection capabilities for Cys-and GSH. UV absorption and fluorescence emission spectra changes revealed distinct shifts upon interaction with Cys-and GSH. Theoretical and experimental studies validated PYR-CG's responsiveness to Cys-and GSH, elucidating its mechanism as a ratiometric probe. Notably, PYR-CG exhibited rapid response kinetics for Cys-and GSH, with low detection limits of 88 nM and 164 nM, respectively. Importantly, PYR-CG demonstrated exceptional selectivity for Cys-and GSH over interfering analytes. Screening of molecules with similar structures to Cys-further affirmed PYR-CG's specificity, particularly towards N-terminal Cys-in peptides. Furthermore, recovery experiments underscored PYR-CG's reliability for quantitative Cys-detection in complex food samples. Our findings highlight the innovative design and practical applicability of PYR-CG, offering a valuable tool for sensitive and selective detection of Cys-in diverse biological and food samples.

Study of the Optical and Structural Properties of Metal-Doped Titanium Dioxide Electrode Prepared by the Sol-Gel Method for Dye-Sensitized Solar Cells

This study presents a strategy to increase the efficiency of dye-sensitized solar cells (DSSCs) by doping titanium dioxide (TiO2) with different magnesium (Mn) concentrations (1, 3, 5, 7, and 9%) generated by the sol-gel process and effectively employed as a photo-anode (the working electrode) for DSSCs. The Doctor Blade method coated the indium-doped tin oxide (ITO) glass with a thin film layer. X-ray diffraction (XRD) was used to evaluate the characteristics of undoped and manganese-doped TiO2, and the results demonstrate that all of the thin films are anatase. The samples were examined using XRD to assess grain size before and after Mn doping. The spectrum of UV-Vis absorption changes; accordingly, as doping increases, the energy gap decreases. The smallest energy gap's value (2.4 eV) is 7% manganese doping. AFM pictures show the average roughness and root mean square of the weight percentage of films doped with 5%. Field effect scanning electron microscope (FE-SEM) studies show that the particle size of thin films gets smaller as more Mn is added, which happens at least as much as 7% Mn doping. The optimal thickness for TiO2 paste over conductive glass is 15 μm, and the cell's power conversion efficiency increased to 0.604074% with an Imax of 4.965 mA, a Vmax of 0.488 V, and a fill factor (FF) of 68.45954%.

Intercalation of quaternary ammonium cations as a key factor of electron storage in MoS2 thin films

Electrochemical intercalation of cations within two-dimensional transition metal dichalcogenides presents a promising route for tailoring their optoelectronic properties. We have now succeeded in modulating the optical properties of MoS2 thin films through electrochemical intercalation of quaternary ammonium cations. The spectroelectrochemical experiments conducted with varying sizes of the intercalant revealed the size-dependent stability of the intercalated MoS2 nanosheets. The observed absorption change of the exciton bands is reversible and arises from the storage of electrons in MoS2 nanosheets and the subsequent weakening of interlayer van der Waals interactions following cation intercalation. This structural change is evidenced by the emergence of A*1g out-of-plane Raman mode. Additionally, the photoelectron spectroscopy reveals the emergence of a lower binding energy component of Mo 3d and the shift in Fermi level to higher energies, confirming the presence of stored electrons in cation intercalated-MoS2. The underlying mechanism of intercalation-induced property modifications in MoS2 discussed in the present study is useful in developing strategies for energy conversion devices.

Micrometric patterning of a borogermanate glass containing terbium by thermal poling to manage luminescence and second order optical properties

Borogermanate glasses containing terbium ions are interesting materials due to their luminescent and magnetic properties. Terbium can present two different oxidation states and the thermal poling technique can be a pertinent way to modulate spatially the oxidation state of these ions. In this work, we demonstrate using a thermo-electrical imprinting process the transfer of micro scaled motifs on the surface of a borogermanate glass containing Tb3+ resulting in a micrometric structuring of the oxidation state of Tb3+/Tb4+ ions. A large change in absorption and luminescence optical properties is observed, arising from the distinct properties of trivalent and tetravalent terbium ions. Correlative micro luminescence, Raman and second harmonic generation measurements were carried out on the patterned poled glass surface. This has demonstrated an accurate concomitant modification of the glass structure accompanying large luminescence changes and the appearance of a second order optical response which could be attributed to a localized space charge implantation. These original results demonstrate how a simple electrical process allows managing multi optical properties but also paves the way to induce static electrical functionalities in a magnetic optical glassy system.

The complexometric behavior of selected aroyl-S,N-ketene acetals shows that they are more than AIEgens

Using the established synthetic methods, aroyl-S,N-ketene acetals and subsequent bi- and multichromophores can be readily synthesized. Aside from pronounced AIE (aggregation induced emission) properties, these selected examples possess distinct complexometric behavior for various metals purely based on the underlying structural motifs. This affects the fluorescence properties of the materials which can be readily exploited for metal ion detection and for the formation of different metal-aroyl-S,N-ketene acetal complexes that were confirmed by Job plot analysis. In particular, gold(I), iron(III), and ruthenium (III) ions reveal complexation enhanced or quenched emission. For most dyes, weakly coodinating complexes were observed, only in case of a phenanthroline aroyl-S,N-ketene acetal multichromophore, measurements indicate the formation of a strongly coordinating complex. For this multichromophore, the complexation results in a loss of fluorescence intensity whereas for dimethylamino-aroyl-S,N-ketene acetals and bipyridine bichromophores, the observed quantum yield is nearly tripled upon complexation. Even if no stable complexes are formed, changes in absorption and emission properties allow for a simple ion detection.

A Spectrophotometric Determination of Amlodipine Drug in Pharmaceutical Preparations Using 2, 6-Dihydroxybenzoic Acid Reagent

In this study, a delicate, exact, and efficient colorimetric spectrophotometric technique was created for the assessment of Amlodipine in its unadulterated structure and in drug arrangements The strategy depends on the response of the optional amine in the medication with the carbonyl gathering in the natural reagent 2, 6 dihydroxy benzoic corrosive within the sight of p-dimethyl amino benzaldehyde to frame a yellow complex (Manich complex). The greatest absorbance was viewed as at 402 nm. Linearity was seen in the scope of 2-40 μg/mL, and the connection coefficient was viewed as 0.9909. The molar absorptivity was viewed as 1.392 × 104 L•mol-1•cm-1. It was observed that the shade of the item was steady and no massive change in absorbance was noticed for as long as 50 minutes a recuperation of 100.596% was gotten. The restriction of discovery (LOD) and cutoff of evaluation (LOQ) were viewed as 0.968 µg/mL and 3.228 µg/mL, individually. The %RSD was 4.32, which demonstrates the precision of the proposed strategy.

An Retrospective Study of Commonly Prescribed Antiepileptic Drugs and it’s Interaction with Other Drugs which are Already in use Respect to Other Disease

Antiepileptic drugs (AED) are increasingly used in the treatment of some non-epileptic neurological diseases and psychiatric diseases. Most of the available data on the use of these agents in clinical conditions other than epilepsy are from case series, uncontrolled studies, or small randomized clinical trials, and their apparent efficacy requires confirmation in well-designed large phase III trials. Interactions between antiepileptic drugs or between antiepileptic drugs and other drugs can be pharmacokinetic or pharmacodynamic. Pharmacokinetic interactions include changes in absorption, distribution ,or eliminate , while pharmacodynamic interactions include synergism and antagonism at the site ,of action. Most clinically significant antiepileptic drug interactions are due to induction or inhibition of drug metabolism. Carbamazepine, phenytoin, phenobarbital and primidone are strong inducers of cytochrome P450 and glucuronide enzymes (as well as P-glycoprotein) and may reduce the effectiveness of concomitantly administered drugs such as oral anticoagulants, calcium antagonists, antimicrobial steroids. Mechanism Oxcarbazepine, eslicarbazepine acetate, felbamate, rufinamide, topiramate (at doses ≥ 200 mg/day) and perampanel (at doses ≥ 8 mg/day) have weaker inducing properties and less tendency to produce interactions mediated by enzyme induction. In contrast to enzyme induction, enzyme inhibition results in decreased metabolic clearance of the affected drug, which can increase serum concentrations leading to toxic effects. Examples of important interactions mediated by enzyme inhibition include valproic-induced increases in serum concentrations of phenobarbital and lamotrigine. There are also interactions where other drugs induce or inhibit the metabolism of antiepileptic drugs. Examples include an increase in serum carbamazepine concentration due to erythromycin and a decrease in serum lamotrigine concentration due to estrogen-containing contraceptives. Pharmacodynamic interactions between antiepileptic drugs may also be clinically important. These interactions can have potentially beneficial effects, such as the combined therapeutic synergy of valproic acid and lamotrigine, or adverse effects, such as the mutual potentiation of neurotoxicity in patients treated with a combination of sodium channel blocking antiepileptic drugs. AEDs are also used to treat psychiatric conditions, particularly bipolar disorder. To date, the AEDs most commonly used to treat this disorder have been carbamazepine and valproic acid, which have shown manic efficacy and likely long-term mood-stabilizing effects in many bipolar patients, including those who are lithium-intolerant. . The availability of new generation AEDs has expanded treatment options for bipolar disorder. Lamotrigine, oxcarbazepine, gabapentin, and topiramate appear to show promise in the treatment of bipolar disorder, both as monotherapy and in combination with traditional mood stabilizers. In addition, newer AEDs appear to have a more favorable tolerability and drug interaction profile than older compounds, thus improving compliance

Small changes, big impact: radical formation of perylene monoimides in photoredox catalysis

The use of organic molecules as photosensitizers in photoredox catalysis is an attractive research field as it has the potential to replace conventionally used photosensitizers, which are based on rare metals. In the context of light‐driven hydrogen evolution catalysis, the radical formation of two perylene monoimide dyes (PMIs) was studied by means of electron paramagnetic resonance (EPR) and UV/Vis spectroscopy. The PMIs were reduced and oxidized both photochemically and electrochemically to study the changes in absorption and EPR signature. A distinct differentiation between the two PMIs as well as a comparison between the oxidative and reductive processes can be made by EPR measurements. UV/Vis measurements showed different features under redox conditions. This study addresses a gap in understanding the radical intermediate formation during photocatalytic processes.

Reactivity-based detection of nitrite ion: Rapid colorimetric and fluorometric response down to nM level

Recent developments in our lab provided significant insight into the structure–reactivity relationship between electronic properties and the detection of nitrite ions. By fine-tuning electron-withdrawing and electron-donating power, the sulfonamide group on aniline moiety was found to be the fastest nitrite probe among the first generation of probe molecules. Based on our understanding of the detection mechanism, our attention was moved to additional modification by installing stronger electron-donating groups on the azo-coupling partner. Accordingly, the bis methoxy group version of the probe molecule was prepared. It showed clean conversion from the probe to the benzo[c]cinnoline product and excellent linear response to very low levels of nitrite ions. Proton NMR and high-resolution mass spectrometer captured the reaction between the probe molecule and nitrite ions. As the reaction with nitrite ion triggers diazonium intermediate formation followed by intramolecular cyclization, both absorption and emission property changes were monitored as the signal readout to assay nitrite ion. In this report, our design principle of a probe molecule and its performance in colorimetric and fluorimetric responses will be discussed. In addition, the low detection limit achieved by leveraging chromatographic separation and assaying by the mass detector will be discussed.

Preparation and characterization of hybrid polypyrrole nanoparticles as a conducting polymer with controllable size

Hybrid polypyrrole (PPy) nanoparticles were prepared using a low-temperature oxidative polymerization process in an acidic solution with polyethyleneimine (PEI) as a template and amine source. The results showed that the nanoparticles have an amorphous structure in the X-ray diffractogram and exhibited good dispersibility in water, uniform size, and a specific conductivity ranging from 0.1 to 6.9 S/cm. The particle size could be tuned from 85 to 300 nm by varying the reactant concentration. Undoping the samples with sodium hydroxide (NaOH) solution altered the optical absorption properties and surface roughness of the particles. However, it did not affect the particle size. The nanoparticles also exhibited optical sensing properties based on their UV–vis absorption changes with the pH. Moreover, nanoparticles could have potential applications in gene delivery and bio-adsorption for contaminant removal. This work demonstrates a simple and effective method for preparing hybrid polypyrrole nanoparticles with controllable size, dispersibility, and conductivity for various nanotechnology, biotechnology, and environmental engineering purposes.