Addition Of Al3 Research Articles

Pyrene Based Schiff Base for Cascade Fluorescent "On-Off" Detection of Aluminium(III) and Fluoride ions and its Applications in Live Cells Imaging.

An easy-to-prepare pyrene-based Schiff base PNZ was synthesized by condensing equimolar amount of 1-pyrenebutyric hydrazide with 2-hydroxy-naphthaldehyde, and employed as a fluorescent chemosensor for in-situ cascade detection of aluminium (Al3+) and fluoride (F-)ions. In DMSO:H2O (1:1, v/v), the weakly emissive PNZ showed a significant fluorescence enhancement at 455 nm selectively upon the addition of Al3+ due to the complexation-induced formation of a pyrene excimer. Schiff base PNZ and Al3+ formed a complex in 2:1 binding ratio with the estimated binding constants of K1:1 = 9826.01 M-1 and K2:1 = 3188.49 M-1. The sensing mechanism was explored by performing quantum mechanical calculations and 1H NMR titration of PNZ with Al3+. The in-situ formed PNZ-Al3+ complex species enabled the fluorescent turn-off detection of F-. Using PNZ and PNZ-Al3+, the concentrations of Al3+ and F- ions can be detected down to 2.89×10-7 M and 1.88×10-7 M, respectively. The cytotoxicity of the PNZ and its ability to bioimage Al3+ and F- ions was examined in the human cervical cancer cell line. Finally, the receptor PNZ was applied for the quantification of Al3+ and F- ions in various real samples, such as tap water, river water, rainwater, mouthwash, and toothpaste.

Metal Ion‐Endows Orange‐Red Light Fluorogenicity of an Imine‐Linkage Probe Embracing Simple Electron Donor‐Acceptor Units

AbstractSelectively tracking and quantifying Al3+ ions is a significant concern to the scientific communities. In the present article, an imine‐linkage electron donor‐acceptor system, DSAN, (E)‐5‐(diethylamino)‐2‐(((2‐hydroxy‐4‐nitrophenyl)imino)methyl)phenol has been introduced which shows Al3+ ions endows red light fluorogenicity which could be utilized for sequential and detection of Al3+ ions and picric acid (PA) in both solid and liquid phases. Upon addition of Al3+ ions into the DSAN solution, an orange‐red fluorescence is noticed at 604 nm caused by the formation of Al3+ ions chelated DSAN complex having detection and quantification limit 0.2 μM and 0.62 μM respectively in dimethylformamide (DMF) medium. The complex formation is found to be a 1 : 1 stoichiometric ratio as evident from Job's plot analysis. Also, the binding affinity value is found to be 3.24×104 M−1 demonstrating a high affinity of DSAN towards Al3+ ions. This orange‐red fluorescence of Al3+ ions chelated DSAN complex solution is quenched due to the introduction of PA. A super handy paper‐strips‐based detection tool also been fabricated utilizing DSAN which could be employed to track trace amounts of Al3+ ions in the solid state. The mechanism involved in the detection of Al3+ ions is elucidated by density functional theoretical analysis.

Modification of Co3O4 by Al2O3: Influence on the reducibility

In this study, we used a coprecipitation method followed by calcination at 500 °C to synthesize undoped and Al3+-doped Co3O4 nanoparticles with different aluminum fractions (x = Al/(Co + Al) = 1/60, 1/30, 1/15, 1/75, 1/6 and 1/5). An addition of Al3+ ions led to a decrease in the average crystallite size from 29 to 11 nm, and growth of the specific surface area from 28 to 91 m2/g. TEM images indicated round and platelet shapes of the nanoparticles. According to HAADF-STEM combined with EDS elemental mapping, the platelet shape particles are Al3+-enriched, while the round shape particles are Al3+-depleted. The origin of Al3+ distribution over the oxide volume is conditioned by the state of the hydroxide precursor. It was shown by XRD that the coprecipitation yielded homogeneous hydroxides only for Al fractions x = 0 and x = 1/5. For the intermediate compositions, the precursors represent a mixture of Co6(CO3)2(OH)8*H2O and Co0.8Al0.2(OH)2(CO3)0.1*nH2O. On the TPR-H2 profiles, reduction peaks for three (Co,Al)3O4 oxides differing in the Al3+ concentration (y) can be found. Two of these oxides with y = 0 and y = 0.2 are formed from different hydroxides, and third one with y ∼0.05 is the result of their mutual interaction. In situ XRD allowed us to interpret the TPR peaks correctly and showed that the reduction of all the oxides occurs in two steps. In the first step, Co3+ → Co2+, and (Co1-yAly)3O4 oxides transform to (Co,Al)O. In the second step, Co2+ → Co0, and (Co,Al)O is reduced into metallic cobalt. In undoped Co3O4, Co3+ → Co2+ and Co2+ → Co0 reduction steps occur at T1 = 280 and T2 = 325 °C, respectively. For Al-depleted (Co1-yAly)3O4 (y ∼ 0.05 in the interior of particles), both reduction steps shift toward higher temperatures T1 = 305 and T2 = 405 °C, respectively. The reduction of Al-enriched (Co0.8Al0.2)3O4 is more difficult; first and second reduction steps occur at T1 = 345 and T2 = 610−690 °C. Therefore, Al3+ ions have a little effect on the first step and very significantly influence the second one. Additionally, it was shown by TEM that after the reduction at 700 °C metallic cobalt particles were surrounded by the Al-enriched oxide shell. Apparently, that is why the addition of even a small amount of Al3+ ions prevents a quick sintering of metallic cobalt observed for pure Co3O4.

Enhanced photovoltaic efficiency in TiO2-based CdS quantum dot-sensitized solar cells by the introduction of ZnO:Al3+ nanoparticles

A technique to fabricate quantum dots-sensitized solar cells (QDSSCs) based on Titanium Oxide (TiO2) and Zinc Oxide (ZnO) nanoparticles (NPs) is reported. ZnO nanocubes of around 65 nm were synthesized by the sol–gel precipitation method. ZnO was doped with Al3+ to enhance the photovoltaic efficiency by promoting electron mobility to form an efficient photoelectrode added to TiO2. Current density–voltage (J-V) characterizations indicate that the addition of Al3+ doping in ZnO crystalline structure in the photoelectrode can significantly improve current densities and consequently the photoconversion efficiency (η) of the QDSSCs, achieving maximum η of 3.4 % with five ZnO nanocubes layers with a 0.0005 M Al3+ doping concentration. While with the undoped sample and bare TiO2, the obtained ήs were 2.85 and 1.93 %, respectively. The improved QDSSC photovoltaic performance was attributed to the increased light harvesting due to a large surface area by introducing Al-doped ZnO nanocubes into the available places of the TiO2 lattice. On the other hand, the increased electrical conductivity due to the Al3+ ion doped into the ZnO lattice at the divalent Zn2+ site allows electrons to move readily into the Al-doped ZnO conduction band. Additionally, according to electron lifetime studies, the Al-doped ZnO nanocubes act as a dielectric layer, enhancing the photogenerated charge extraction process due to the introduction of lattice defects, causing intermediate levels to obtain higher electron recombination resistance.

Fluorescent probes based on N-CQDs: For direct detection of food additives STPP and Al3+

Sodium tripolyphosphate (STPP), as one of the many food additives, can cause gastrointestinal discomfort and a variety of adverse reactions when ingested by the human body, which is a great potential threat to human health. Therefore, it is necessary to develop a fast, sensitive and simple method to detect STPP in food. In this study, we synthesized a kind of nitrogen-doped carbon quantum dots (N-CQDs), and were surprised to find that the addition of STPP led to the gradual enhancement of the emission peaks of the N-CQDs, with a good linearity in the range of 0.067–1.96 μM and a low detection limit as low as 0.024 μM. Up to now, there is no report on the use of carbon quantum dots for the direct detection of STPP. Meanwhile, we found that the addition of Al3+ effectively bursts the fluorescence intensity of N-CQDs@STPP solution and has a good linear relationship in the range of 0.33–6.25 μM with a lower detection limit of 0.24 μM. To this end, we developed a fluorescent probe to detect STPP and Al3+. In addition, the probe was successfully applied to the detection of bread samples, which has great potential for practical application.

Selective Chromo-Fluorogenic Chemoprobe for nM Al3+ Recognition: Experimental and Living-Cell Applications.

A rhodamine based chemoprobe BESN was engineered and employed as a selective ''OFF-ON'' chromo-fluorogenic sensor for Al3+ in H2O:MeOH (1:9, v:v). Notable changes in the absorption and emission spectra of BESN were clearly detectable upon the addition of Al3+. Sensitivity and binding mechanism studies demonstrated a good sensing performance of BESN with nanomolar detection limit (130nM), and it was found to be highly selective towards interfering metal ions. Besides, the binding constant between BESN and Al3+ was found to be 3.19 × 103M-1. Then, the validation study of BESN for Al3+ was performed based on significant analytical parameters and statistical tests. The binding of Al3+ with BESN (1:1) was probed via infrared, high-resolution mass and emission (Job's plot) spectroscopy measurements. The sensing performance of BESN could make it ideal chemosensor for real applications including vegetable, tuna fish and water samples, also for Smartphone and test-kit applications. The recovery values of the BESN to Al3+ were estimated within a range from 95.13% to 105.30% for water, 94.63% to 109.62% for tuna fish and 94.80% to 109.80% for vegetable samples. Additionally, the BESN has very low cytotoxicity and was triumphantly utilized for the recognition of Al3+ in living-cells.

Interfacial effect of coexisting salt cations on extraction of erbium using gas bubble-supported organic liquid membrane

The conventional understanding about the specific ion effect from the coexisting electrolyte salts on the extraction and separation of target metal ions during liquid-liquid solvent extraction cannot explain some abnormal phenomena when more than one kind of background ions coexisting in the aqueous feed solutions to be separated. In this work, the specific ion effect of coexisting ions, Mg2+ and Al3+ as the example here, on extraction of Er3+ ion was investigated using gas bubble-supported organic liquid membrane. A very interesting phenomenon was noticed that, the difference in Er3+ extraction percentage was only 11.7 % in the Er-Mg solution system with addition of Al3+ ions or not, while it could reach 18.0 % in that of Er-Al with addition of Mg2+ ions or not. When Mg2+ and Al3+ coexisted simultaneously in the feed solutions, their specific ion effect on improving the extraction percentage of Er3+ was not equal to the sum of that when only single Mg2+ or Al3+ exists, respectively. Furthermore, a thinner organic liquid membrane supported by gas bubbles was in favor of enhanced interfacial enrichment of Er3+ and its diffusion mass transfer near the interface. During gas bubble-supported organic liquid membrane extraction, Mg2+ ions exhibited more obvious specific ion effect due to a weaker interaction with P507 molecules. However, a stronger hydration ability of Al3+ than Mg2+ ions induces a stronger competition of Al3+ with P507 molecules. Therefore, the coexistence of Mg2+ and Al3+ ions could play a synergistic role in enhancing enrichment of Er3+ on the basis of the mutual interference from the synergistic specific ion effect of coexisting Al3+ and Mg2+ ions. The research helps thoroughly understand the regulation mechanism on the synergistic specific ion effect for selective extraction of specified ions from the complex solutions containing multiple coexisting background ions.

Development of a Pyrone-Fused Tricyclic Scaffold-based Ratiometric Fluorescent Probe for Al3+ Detection.

Aluminum (Al3+) is environmentally abundant and can harm living organisms in various ways, such as by inhibiting root growth, damaging faunal nervous systems, and promoting tumor cell proliferation. However, the dynamics of Al3+ in living organisms are largely unknown; thus, detecting Al3+ in the environment and organisms is crucial. Fluorescent probes are useful tools for the selective detection of metal ions. In particular, ratiometric fluorescent probes exhibit a detection response at two different maximum fluorescence emission wavelengths; which is advantageous for avoiding the influence of background fluorescence. A novel pyrone-fused tricyclic scaffold-based ratiometric fluorescent probe for detecting Al3+, ethyl 11-imino-1-oxo-3-phenyl-1H,11H-pyrano[4,3-b] quinolizine-5-carboxylate (PQ), was developed in this study. The PQ fluorescence blue shifted from 505 to 457nm upon the addition of Al3+. The blue shift was accompanied by a change in the fluorescence color of the PQ solution from green to blue. Fluorescence titration experiments demonstrated that the fluorescence intensity ratio at the two peaks of interest (457/505nm) increased in a concentration-dependent manner upon the addition of Al3+. Moreover, this study demonstrated that a PQ-soaked paper displays a visible color change under ultraviolet light upon exposure to Al3+. The above results suggest that PQ is an effective ratiometric probe for the detection of Al3+ in the environment. Future studies will be conducted to introduce various substituents and develop fluorescent probes by leveraging the fluorescence property of a pyrone-fused tricyclic scaffolds.

A biologically inspired fluorescent probe with enhanced sensing performance for detection of Al3+ based on metal replacement strategy

Salicylaldehyde acyl-hydrazone derivatives have been widely applied to design fluorescent probe for Al3+ detection, but they are always restricted to detect Al3+ in water and actual samples by their poor solubility, low sensitivity, and long response time. Biologically inspired, four salicylaldehyde acyl-hydrazone compounds were designed and synthesized and H4L1 as one of them was selected for in-situ assembly of the ytterbium complex (FP-Al), which has been developed to be a new fluorescent probe for Al3+ detection by the central mental displacement process. The in-situ structure transformation from FP-Al to Al-L was fully characterized by X-ray crystal structure analysis, 1H NMR, FT-IR, and spectral analysis. The intrinsic driving force was explained and elaborated by theoretical calculation. FP-Al showed a significant visible fluorescence enhancement and near-infrared luminescence decreased upon the addition of Al3+. Compared with the ligand H4L1, FP-Al showed enhanced sensing performance during Al3+ detection, especially in improving water solubility and selectivity to Al3+, promoting response speed, reducing background fluorescence and increase cell-membrane permeability. The application of spontaneous metal replacement reaction might be able to provide a new strategy to develop high-performance optical chemo-sensors.

A novel fluorescence sensor based on Al3+-mediated aggregation of gold nanoclusters for determination of citric acid in beverages.

This paper revealed a new strategy for citric acid (CA) detection using aggregation-induced emission (AIE)-based fluorescent gold nanoclusters (AuNCs). AuNCs was synthesized using glutathione (GSH) as the template and reducing agent and used as the fluorescent probe to detect CA under aluminum ion (Al3+) mediation. The fluorescence intensity of AuNCs increased about 4 times with the addition of Al3+, but the enhanced fluorescence was quenched after the addition of CA. Based on this fluorescence phenomenon, an "on-off" fluorescence strategy was designed for the sensitive determination of CA and a linear detection range for CA was achieved within 0-80.0 μM. In addition, the developed probe exhibited high selectivity and accuracy for determination of CA. The mechanism of fluorescence enhancement and quenching of AuNCs was explored in detail. The established probe was used successfully for CA detection in beverages. The spiked recoveries from 97.50% to 103.67% were gratifying, which indicated the probe had potential prospects for detecting CA in food.

Dielectric properties of the Ca0.25Cu0.75-xAlxTiO3 ceramics: experimental and computational investigations

In this study, we employed a solid-state reaction method to synthesize Ca0.25Cu0.75-xAlxTiO3 ceramics, investigating the impact of Al doping at concentrations of x = 0 and 0.0125. Notably, all ceramics exhibited a primary phase of Ca0.25Cu0.75TiO3. The addition of Al3+ induced a significant increase in grain size. Density functional theory analyses revealed a preferential occupation of Cu sites by Al, leading to liquid-phase sintering processes attributed to excess Cu. Moreover, it was also found from DFT that the Al dopant cannot induce an oxygen vacancy in the lattice. Charge density analysis revealed that Cu+ and Ti3+ observed via XPS originate from the presence of an oxygen vacancy. The Ca0.25Cu0.7375Al0.0125TiO3 ceramic exhibited a very high dielectric permittivity of 9.23 × 104 and a low dielectric loss tangent of 0.057 at 1 kHz and room temperature. Importantly, the dielectric permittivity exhibited impressive stability over a temperature range of −60 °C to 110 °C, perfectly meeting the practical requirements for utilization in X5R ceramic capacitors. Our investigation indicates that the improved dielectric properties may be attributed to enhanced grain boundary responses, influenced by oxygen enrichment and the presence of metastable insulating layers at grain boundaries. Combining experimental findings with theoretical evidence, our study elucidates that the excellent dielectric properties of the Ca0.25Cu0.7375Al0.0125TiO3 ceramic originate from an extrinsic effect arising from grain boundary enhancement. This work not only contributes to advancing the understanding of the underlying mechanisms governing dielectric behavior in doped ceramics, but also emphasizes the potential of Ca0.25Cu0.7375Al0.0125TiO3 as a promising material for applications demanding superior dielectric performance.

Turn-on detection of Al3+ ions using quinoline-based tripodal probe: mechanistic investigation and live cell imaging applications.

In this study, an easily synthesizable Schiff base probe TQSB having a quinoline fluorophore is demonstrated as a fluorescent and colorimetric turn-on sensor for Al3+ ions in a semi-aqueous medium (CH3CN/water; 4 : 1; v/v). Absorption, emission and colorimetric studies clearly indicated that TQSB exhibited a high selectivity toward Al3+, as observed from its excellent binding constant (Kb = 3.8 × 106 M-1) and detection limit (7.0 nM) values. TQSB alone was almost non-fluorescent in nature; however, addition of Al3+ induced intense fluorescence at 414 nm most probably due to combined CHEF (chelation-enhanced fluorescence) and restricted PET effects. The sensing mechanism was established via Job's plot, NMR spectroscopy, ESI-mass spectrometry, and density functional theory (DFT) analyses. Furthermore, to evaluate the applied potential of probe TQSB, its sensing ability was studied in real samples such as soil samples and Al3+-containing Digene gastric tablets as well as on low-cost filter paper strips. Fluorescence microscopy imaging experiments further revealed that TQSB can be used as an effective probe to detect intracellular Al3+ in live cells with no cytotoxicity.

Water-soluble chiral coordination polymers of Li+, Na+, K+, and Ba2+ with an anionic iron(III) complex of a L-threonine derivative and a significant red shift of visible spectra with Al3+ salt.

Four salts of an anionic iron(III) bis-complex, [Fe(LL-thr)2]1-, were synthesized from water or methanol. H2LL-thr is a tridentate ligand derived from the L-threonine amino acid, and the cations used are Li+ (1), Na+ (2), K+ (3), and Ba2+ (4). Single-crystal X-ray diffraction showed that all the complexes are coordination polymers of different dimensionalities. The iron(III) complex binds to cations through its coordinated phenolate and non-coordinated carboxylate oxygen atoms. While Li+ forms a linear chain, all others have a pair of bridged cations intervening the iron(III) complexes. The 3D network of Ba2+ salt has a sizeable solvent-accessible space occupied by aquated chloride ions. The differences in circular dichroism (CD) spectra and significantly lower conductance values in water and methanol support partial retention of the polymeric nature in methanol. The visible spectra of 4 in methanol or water showed an ∼10 nm shift of the charge transfer bands from 3. However, the addition of Al3+ salt to 2 showed a significant colour shift. Further investigation confirmed that the colour shift is due to partial protonation of the complex with protons generated from salt hydrolysis. Most reports on visual aluminium detection consider aluminium's binding as the shift's source. The present results show that protonation due to hydrolysis of aluminium salt can skew the observation.

A Novel ppb-Level Sensitive and Highly Selective Europium-Based Diketone Luminescent Sensor for the Quantitative Detection of Aluminum Ions in Water Samples

A novel Eu(tta)3([4,4′-(t-bu)2-2,2′-bpy)] complex (tta-thenoyltrifluoroacetone), a ratiometric luminescent-based optical sensor for the quantitative determination of aluminum ion, is synthesized and characterized using XRD and 1H NMR. The XRD data reveal the slightly distorted octahedral structure. The complex displays a bright red emission at 613 nm in methanol which is characteristic of europium (III) complexes. Upon the addition of Al3+ ions, the red emission disappears, and a new blue emission at 398 nm emerges, manifesting the ratiometric nature of the complex. The turn-off of the red emission and turn-on of the blue emission are attributed to Eu-Al trans-metalation, as supported by Raman data that show the emergence of Al-O vibrations at 418, 495, and 608 cm−1 concomitant with the disappearance of Eu-O and Eu-N bond vibrations. Most aluminum sensors are known to suffer from interferences from other metals including Cu2+, Co2+, and Cd2+. However, the sensor reported here is tested for 11 common cations and shows no interference on sensitivity. To the best of our knowledge, this is the first known Eu-based luminescence sensor that successfully exhibited the ability to detect aluminum ions in ppb levels in aqueous environments. The calculated Al3+ binding constant is 2.496 × 103 ± 172. The complex shows a linear relationship in the range of 0–47.6 ppb (1.76 × 10−6 M) Al3+ and the limit of detection (LOD) is 4.79 ppb (1.77 × 10−7 M) in MeOH. ICP-OES is used for validation of the sensor complex in water and then it was used for quantitative detection of Al3+ ions in water as a real-life application. The complex can accurately detect Al3+ ions in the range of 4.97–24.9 ppb (1.84 × 10−7 M–9.2 × 10−7 M) with an LOD of 8.11 ppb (2.99 × 10−7 M). Considering that the aluminum ion serves no recognized function within the human body, its accumulation can lead to severe neurological disorders, including Parkinson’s and Alzheimer’s diseases. With the LOD value significantly lower than the WHO-recommended maximum permissible level of 200 ppb for aluminum in drinking water, even without high-power laser-aided signal enhancement, the sensor shows promise for detecting trace amounts of aluminum contamination in water. Therefore, it can significantly aid in the monitoring of even the smallest aluminum ion contamination in drinking water, industrial effluents, and natural water bodies.

Effect of aluminum and manganese ions on the chlorination of polyamide membranes

The deterioration of separation performance of polyamide membranes after chlorine exposure is a core issue in the application process of membrane technology. The co-existence of metal ions (i.e., Al3+ and Mn2+), which are ubiquitous in different types of water bodies, may complicate the chlorination process. This study systematically evaluated membrane degradation under the simultaneous presence of free chlorine and Al3+ or Mn2+. The membrane water flux after chlorine exposure of 2400 mg/L·h was decreased by 70 %, of which 49 % was resulted from chlorine exposure, attributing to competing effects of the decreased hydrophilicity (contact angle increased from 56° to 68°) and cross-linking degree (Onet/N ratio increased from 1.1 to 2.3). The changes in the physiochemical properties of membranes were due to chlorination and hydrolysis induced by chlorination. The addition of Al3+ or Mn2+ to chlorine resulted in a further reduction of 8 %–13 % for water flux, and a variation as high as 21 % (increase) and 15 % (decrease) for salt rejection compared to virgin membrane at different exposure periods. These cations similarly resulted in a more hydrophobic membrane surface with varied surface charge and the formation of deposition layers. In addition, Al3+ and Mn2+ did not affect chlorination degree (chlorine incorporation). However, Al3+ promoted chlorination-promoted hydrolysis, while Mn2+ inhibited, reflected by the opposite trends of Onet/N.

An oxazole-derived Schiff base as a multifunctional fluorescence sensor towards Al3+ and Ga3+ in different media

A facile Schiff base derivative N′-(2, 3-dihydroxybenzylidene)-5-(naphthalen-1-yl)oxazole-4-carbohydrazide (G3) was constructed and synthesized through the reaction of 5-(naphthalen-1-yl)oxazole-4-carbohydrazide with 2,3-dihydrobenzaldehyde, which achieved the distinct recognition for two kinds of IIIA group metal ions (Al3+, Ga3+) in different media. G3 performed an enhanced blue luminescence upon addition of Al3+ in CH3OH/H2O buffer solution. As well, G3 exhibited a remarkable fluorescence enhancement toward Ga3+ with a color change from colorless to green in DMSO/H2O buffer solution. Therefore, G3 was applied as a multifunctional fluorescence sensor for Al3+ and Ga3+. The molar ratio for G3 towards Al3+ and Ga3+ was both verified to be 1:2, and the possible sensing mechanism was demonstrated by Job's plot, mass spectrometry titration and theoretical calculation. What’ more, G3 could be used to determinate target ions in real water samples with favorable recovery, which implied a wide prospect for application. And more importantly, the fine difference on microstructure causing the macroscopic performance of sensors in the buffer solution was revealed through the contrastive study of G3 and G1 in previous work.

An Off‐On‐Off Benzoxazole‐Based Fluorosensor for Relay Detection of Al3+ Ions and Explosive Nitroaromatic Compounds

AbstractDeveloping fluorosensors for the efficient detection of aluminium (Al3+) ions and electron‐deficient nitroaromatic compounds (NACs) is in high demand but challenging. This report introduces a benzoxazole‐based off‐on‐off fluorosensor for the cascade detection of Al3+ ions and electron‐deficient NACs. Upon addition of Al3+ ions, the probe BPMP displays a bright blue fluorescence under the exposure of 365 nm UV light radiation in an H2O/DMSO (1 : 1 v/v) medium due to the chelation of Al3+ ions disrupting the ESIPT process involved in probe BPMP. The detection limit for Al3+ ions is found to be 13 nM, which is significantly lower than many chemosensors available in the literature. The 1 : 1 stoichiometry of the chelated complex between BPMP and Al3+ ions is confirmed by Job′s plot and also by 1H NMR titration investigation. More importantly, the Al3+ ions chelated BPMP complex is further used as a fluorescent turn‐off probe for the detection of electron‐deficient NACs with the detection as low as 10−7 M. Based on these chemically encoded inputs and the corresponding optical output, we have constructed one input and one output based YES, and NOT logic gate with BPMP and BPMP‐Al3+ complex as input respectively and also dual inputs and single optical output‐based INHIBIT logic gates. Also, BPMP‐doped paper strips‐based test kit analysis has been demonstrated as a displayable photonic device for on‐spot detection. The performance of BPMP and Al3+ ions chelated BPMP complex toward Al3+ ions and electron‐deficient NACs demonstrated that BPMP could be served as a sensitive probe and could be employed for real sample analysis.

Exploring the highly selective Fe(III) and Al(III) triggered “OFF-ON” ellagic acid based fluorescent sensor: Spectroscopic, structural elucidations and dual-response mechanism

Owing to the favorable efficiency and low cost, dual-response fluorescent sensors play critical roles in the development of fluorescence assay systems. In this paper, the dual-response fluorescent of ellagic acid was reported both turn-off to Fe3+ and turn-on to Al3+, as well as the effects of pH by UV–vis absorption and fluorescence emission spectroscopy. The addition of Fe3+ changed the color of the ellagic acid solution from colorless to grey-green, and the fluorescence emission was quenched. In contrast, the addition of Al3+ changed the colorless solution to light yellow, and the fluorescence emission was significantly enhanced. The coordination constants of EA to Fe3+ and Al3+ were determined to be 3.42 × 104 M−1 and 2.83 × 105 M−1, respectively, according to Job's plot. By comparing the reaction with urolithin and its derivatives, the fluorescence emission mechanism of the ellagic acid reaction with Fe3+ and Al3+ was elucidated. The detection limits of EA for Fe3+ and Al3+ were 9.80 × 10−7 and 1.90 × 10−7 M, respectively.

Flotation separation of fluorite and calcite using anhydrous glucose and aluminum sulfate as a combined depressant

The effective flotation separation of fluorite and calcite is a critical problem in the mineral processing industry owing to their similar physicochemical characteristics. In this study, the effect of glucose (Glu) and Al3+ on the flotation separation of fluorite and calcite was studied using micro-flotation experiments, scanning electron microscopy (SEM), solution chemistry calculation, X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT). The micro-flotation experiments demonstrate that the combination of Glu and Al3+ had a significant depression effect on calcite. However, it slightly affected fluorite flotation. The SEM results indicate that Glu and Al3+ had a greater tendency of absorption on the calcite surface than that of fluorite. The solution chemistry calculation and XPS analysis exhibit that the increased selective depression of Glu on calcite with the addition of Al3+ was due to the formation of Al (OH) 3 and Al2O3 on the calcite surface. The DFT results exhibit that Ca-O bonds were formed when Glu interacted with fluorite. Additionally, Ca-O, C–H, and H-O bonds were formed when Glu interacted with the surface of calcite. The surface bonding characteristics of Glu with fluorite and calcite led to a difference in the adsorption energy. The glucose and Al2O3 glucose formed on the surface of calcite improved the adsorption through Al-O bond, which increased the adsorption sites on the surface of calcite and enhanced the depression effect of Glu on calcite.

Fluorescent properties based on ESIPT and TICT of novel acylhydrazone-based probe and its sensing mechanism for Al3+: A TD-DFT investigation

By using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, the fluorescent process and sensing mechanism of N′-(2-hydroxybenzylidene)isoquinoline-3-carbohydrazide (NHIC) probe for Al3+ detection were explored in detail. For NHIC, twisted intramolecular charge transfer (TICT) is induced by existed state intramolecular proton transfer (ESIPT). Probe NHIC can undergo ESIPT process in the stepwise pattern, and then a stable double proton-transfer (DPT) structure is formed. There are two non-emissive TICT states (TICT1 and TICT2) existing in NHIC. TICT2 is responsible for the weak fluorescence observed experimentally. After the addition of Al3+, the coordination bond is formed between NHIC and Al3+, the TICT state is prohibited, and the strong fluorescence is switched on. It is evident that the twisted C-N single bond belonging to acylhydrazone part of NHIC results in its TICT state. We hope that our study can throw some light on the development of switch-on probe.