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Salicylic acid (SA) is a signaling molecule that plays an important role in the regulation of many physiological processes in various plants and is one of the organic micromolecular compounds widely used in the pharmaceutical and chemical industries. In this research, a colorimetric salicylic acid sensor based on gold nanoparticles (AuNPs), a plasmonic nanoparticle, was developed. The plasmon resonance absorption band of AuNPs at 525.5 nm was used for the detection of SA. The pH and AuNPs concentration were optimized to find the suitable operating conditions. Under optimum conditions, the linear working range of the AuNPs-based colorimetric sensor is 7.5-100.0 µM with a detection limit of 0.86 µM. The colorimetric sensor exhibits good selectivity and stability. The analytical applicability of the AuNPs-based colorimetric sensor was investigated by determining the SA content in orange., Author(s): Zehra O. Erdogan [sup.1] , Semanur Badem [sup.1] Author Affiliations: (1) https://ror.org/04fbjgg20, grid.488615.6, 0000 0004 0509 6259, Pharmacy Services, Vocational School, Yuksek Ihtisas University, , 06291, Ankara, Türkiye Salicylic [...]

Author(s): Jitthu Joseph [sup.1] , G. Uma [sup.2] , M. Umapathy [sup.2] , C. S. Prajapati [sup.3] , M. Manjunatha Nayak [sup.1] Author Affiliations: (1) grid.34980.36, 0000 0001 0482 5067, [...], This paper addresses the problem of estimation of hydrogen gas concentration using current output from a sensor chip, integrated with a thin film of ZnO as a sensing layer and inbuilt microheater to obtain desired operating temperature by proposing an appropriate algorithm. The proposed algorithm minimizes the estimation delay while maximizing the estimation accuracy. The proposed algorithm also accounts for the variation in sensor performance with relative humidity. The key features of the proposed algorithm are low computational complexity, low memory requirements, compatibility with any metal-oxides-based hydrogen sensors with independent calibration or turning points, and minimal requirements to the calibration time. As proof of concept, a demonstration of the algorithm efficiency is evaluated by estimating hydrogen concentration using ZnO thin film-based gas sensor device and comparing its performance with available state-of-the-art hydrogen sensor algorithm outputs.

Author(s): Vikesh Kumar Singh [sup.1] , Anandveer Sindhu [sup.1] Amit [sup.2] Author Affiliations: (1) grid.411141.0, 0000 0001 0662 0591, Department of Chemistry, Meerut College Meerut, C.C.S. University Meerut, , Meerut, [...], A ruthenium-bipyridine based fluorescent chemosensor was employed for the fluorometric and colorimetric Cu(II) detection in 100% aqueous medium. The successive emission quenching of the chemosensor by Cu(II) produced quenching constant (K.sub.SV) of 1.85 x 10.sup.5 M.sup.-1. Binding constant (K.sub.b) and the detection limit values for Cu.sup.2+ ion by absorption titration were calculated as 9.87 x 10.sup.6 M.sup.-1 and 0.6 [micro]M, respectively. A competitive binding method was used to investigate selectivity toward Cu ion in the presence of other metal ions. Reversibility studies were performed by adding an excess amount of sulfide ion. Reversible cycles and corresponding logic gate were also generated by absorption change. Binding of the chemosensor to Cu.sup.2+ occurs in a 1 : 1 stoichiometry using Job's analysis. Cu(II) binding with the chemosensor was established by spectroscopic methods.

Author(s): Lidong Shan [sup.1] , Baozhen Li [sup.2] , Wei Fu [sup.3] Author Affiliations: (1) grid.12527.33, 0000 0001 0662 3178, Department of Chemistry, Tsinghua University, , 100084, Beijing, China (2) [...], The detection of Fe ions is of great significance for monitoring environmental hazards and disease diagnosis. Herein, a new organic molecule (4,12-diphenylnaphtho-[2,1,8-mna]acridine) with quantum yields up to 68% was obtained by tandem cyclization synthetic strategy, and the fluorescent sensor for highly sensitive and selective detection of Fe.sup.3+ has been demonstrated. Interestingly, the fluorescence red shifted significantly, and the solution changed from colorless to yellowish green in the presence of Fe.sup.3+, indicating that the synthesized compound can detect Fe.sup.3+ with the naked eye. Furthermore, according to the Stern- Volmer equation, the quenching constant K.sub.SV was calculated to be 1.78 x 10.sup.5 M.sup.-1. The limit of detection of the sensor for Fe.sup.3+ is 0.6 [mu]M, which is lower than the detection limit currently reported for most organic molecules. In addition, we have shown that the synthesized organic molecule exhibits high photoresponsivity. This interesting property enables it to be applied in optoelectronic device fields, which offers alternative selectivity for the multifunctional application of 4,12-diphenylnaphtho-[2,1,8-mna]acridine.

Author(s): Eman Yossri Frag [sup.1] , Sally A. Elashery [sup.1] , Ahmed. M. A. Ali [sup.1] Author Affiliations: (1) grid.7776.1, 0000 0004 0639 9286, Chemistry Department, Faculty of Science, Cairo [...], A carbon electrode utilizing an ion pairing agent for the potentiometric determination of nonyltrimethylammonium bromide (NTAB) was developed. The sensitivity of the developed sensor was established through the formation of ion pair between NTAB and the proposed ion pairing agent on the surface of the sensor paste which was characterized by morphological tools. The developed sensor revealed a monovalent Nernstian slope of 58.4 ± 0.8 mV/decade within the acceptable working concentration range of NTAB from 1.0 x 10.sup.-6 to 0.01 M with the detection limit of 1.0 [mu]M.

Author(s): A. A. Brechalov [sup.1] , E. S. Babitova [sup.1] , V. V. Timoshenko [sup.1] , V. V. Eremin [sup.1] , E. O. Kalinin [sup.1] , D. S. Kalyagin [sup.1] [...], A new type of potentiometric sensor for cesium ions based on a crown ether (dibenzo-21-crown-7) is proposed; its analytical characteristics are presented: limit of detection, slope of electrode function, selectivity to a number of interfering ions, and the working pH range of solutions.

Author(s): Hikmat Hikmat [sup.1] Aprilia Nur Tasfiyati [sup.1] Author Affiliations: (1) Research Center for Chemistry, National Research and Innovation Agency (BRIN), , 15314, Tangerang Selatan, Indonesia Phosphorus is one of [...], In this study, polypyrrole-based molecularly imprinted polymer (MIP) containing phosphate selective site as a conductive polymer material for phosphate ion sensor was successfully synthesized and characterized. The synthesis of MIP-phosphate was carried out using pyrrole as a functional monomer by cyclic voltammetry on the surface of gold wire electrode. The MIP-phosphate electropolymerization was performed in potential range from -0.8 to 0.6 V at a scan rate of 100 mV/s for 10 cycles. According to the FTIR spectra and visual observation of SEM images, the MIP-phosphate was successfully synthesized as a homogenous and well-ordered porous structure. The MIP electrode response to phosphate was examined by potentiometry method, showing an excellent linear response for [Formula omitted], [Formula omitted], and [Formula omitted] within the concentration range of 1 x 10.sup.-7 to 0.1 M with good sensitivity. The selectivity coefficient result also indicates good selectivity toward phosphate ions against the interfering anions (Cl.sup.-, [Formula omitted], and [Formula omitted]).

Author(s): A. N. Zyablov [sup.1] Vu Hoang Yen [sup.1] [sup.2] Author Affiliations: (1) grid.20567.36, 0000 0001 1013 9370, Faculty of Chemistry, Voronezh State University, , 394018, Voronezh, Russia (2) grid.491482.2, [...], A piezoelectric sensor was modified by a selective material on the basis of a molecularly imprinted polymer (MIP) with sodium benzoate (E211) imprints. The values of the imprinting factor and the selectivity coefficient of the MIP-E211-sensor were calculated to assess its ability to recognize target molecules. The results of the determination of sodium benzoate in liquids by the piezoelectric sensor and by HPLC were compared. The relative standard deviation of the results of the determination did not exceed 10%. The limit of detection for sodium benzoate using the MIP-sensor was 2 mg/L. The absence of a matrix effect on the analytical signal of the MIP-based piezoelectric sensor was revealed using the standard addition method. The concentration of sodium benzoate in soft drinks (Yes! Fruit, Chai Kholodnyi Zelenyi (Cold Green Tea), Aqua Minerale "Mint Lyme") was determined using the MIP-based piezoelectric sensor.

The water flow through sponges is regulated by their contractile behaviour including contraction and expansion of the aquiferous system, which leads to shifting oxygen levels in the sponge interior. Still, knowledge of spatial and temporal anoxia in sponges is lacking, but important in elucidating interactions between sponge hosts and their microbiomes. We combined 2-D luminescence lifetime imaging of oxygen with simultaneous time-lapse recordings of the sponge exhalant opening (osculum) to unveil temporal as well as spatial oxygen dynamics caused by contractile behaviour in single-osculum explants of the demosponge Halichondria panicea. The present study reveals an intrinsic concentric deoxygenation pattern in explants during episodes of osculum contraction generating an oxygen gradient with increasing concentrations towards the explant periphery. Four sponge explants faced 25 episodes with substantial changes in internal oxygen and anoxia which prevailed for 4.4 h of the total 92.0 h observation period. The 2-D images revealed that the total area of the explant experiencing anoxia during periods of osculum contraction-expansion varied between 0.01 and 13.22% and was on average 7.4 ± 4.4% for all sponge explants. Furthermore, oxygen respiration, as approximated by the rate of change of oxygen concentration during deoxygenation of the explant interior, was similar throughout the oxic parts of the explant base. The resolved 2-D dynamics provide an unprecedented insight into the internal O.sub.2 distribution of sponges and complement the traditional point measurements of oxygen sensors., Author(s): Lars Kumala [sup.1] [sup.2] , Morten Larsen [sup.1] , Ronnie N. Glud [sup.1] [sup.3] [sup.4] [sup.5] , Donald E. Canfield [sup.1] [sup.3] Author Affiliations: (1) grid.10825.3e, 0000 0001 0728 [...]

Due to their simplicity and operating mode, magnetic loops are one of the most used traffic sensors in Intelligent Transportation Systems (ITS). However, at this moment, their potential is not being fully exploited, as neither the speed nor the length of the vehicles can be surely ascertained with the use of a single magnetic loop. In this way, the vast majority of them are only being used to count vehicles on urban and interurban roads. For this reason, in order to contribute to the development of new traffic sensors and make roads safer, this paper introduces a theoretical study to explain the design and peculiarities of the innovative double loops, how to calculate their magnetic field and three different methods to calculate their inductance. Finally, the different inductance values obtained by these three methods will be analyzed and compared with experimental measurements carried out by our research group in order to know which method is more accurate and if all of them are equally reliable., 1. Introduction Magnetic loops are the most common sensors on roads around the world since they are an affordable and highly developed technology with a simple operation that is not [...]