Monitoring of Hypochlorite Level in Fruits, Vegetables, and Dairy Products: A BODIPY-Based Fluorescent Probe for the Rapid and Highly Selective Detection of Hypochlorite.

Hypochlorite/hypochlorous acid (ClO-/HOCl), among the diverse reactive oxygen species, plays a vital role in various biological processes. Besides, ClO- is widely known as a sanitizer for fruits, vegetables, and fresh-cut produce, killing bacteria and pathogens. However, excessive level of ClO- can lead to the oxidation of biomolecules such as DNA, RNA, and proteins, threatening vital organs. Therefore, reliable and effective methods are of utmost importance to monitor trace amounts of ClO-. In this work, a novel BODIPY-based fluorescent probe bearing thiophene and a malononitrile moiety (BOD-CN) was designed and constructed to efficiently detect ClO-, which exhibited distinct features such as excellent selectivity, sensitivity (LOD = 83.3 nM), and rapid response (<30 s). Importantly, the probe successfully detected ClO- in various spiked water, milk, vegetable, and fruit samples. In all, BOD-CN offers a clearly promising approach to describe the quality of ClO--added dairy products, water, fresh vegetables, and fruits.

A unique triple-channel fluorescent probe for discriminative detection of cyanide, hydrazine, and hypochlorite.

Herein, the first triple-channel fluorescent probe, TTB, excited at the same wavelength (λex = 360 nm) in the same sensing medium for the detection and discrimination of cyanide, hydrazine, and hypochlorite, is disclosed. While a fluorescent white color appeared (λem = 470 nm) with the addition of cyanide ion into the probe solution, upon addition of hydrazine and hypochlorite, green (λem = 503 nm) and orange (λem = 585 nm) fluorescent colors, respectively, were observed. A naked-eye detection for the three ions was documented. With the appearance of orange color, a mega Stokes shift of 175 nm was observed. The probe exhibited excellent selectivity and lower detection limits of 0.24 µM, 4.1 nM and 0.27 µM, and dynamic ranges of 0.0-2.0 µM, 0.0-0.05 µM and 0.0-2.0 µM for cyanide, hydrazine and hypochlorite, respectively. The sensing mechanism was investigated through computational studies before and after the addition of cyanide, hypochlorite, and hydrazine, applying density functional theory (DFT), along with the calculation of optical properties by time-dependent DFT (TD-DFT) method. The results were found to be in good agreement with the experimental values. Remarkably, the probe, TTB, successfully detected cyanide, hydrazine, and hypochlorite in complex water samples. Moreover, the detection of cyanide was successfully performed in apricot kernels, as well as hypochlorite in fruits and vegetables.

An Anthracene and Indole-based Fluorescent Probe for the Detection of Chromium(III) Ions in Real Water Samples.

A novel fluorescent probe possessing anthracene with an indole unit was designed and synthesized to detect chromium(III) ions (Cr3+) with high sensitivity and selectivity. The probe was synthesized in one step by mixing two commercially available chemicals, 2-aminoanthracene and Indole-5-carboxaldehyde. The probe molecule (ANT-In) demonstrates distinct properties, for instance, "turn-on" fluorescence response, high sensitivity and selectivity in less than one minute, and low detection limit (0.2 µM) via hydrolysis of the C = N bond. Additionally, the probe ANT-In was successfully used to identify the presence of chromium(III) ions in real water samples.

Tetraphenylethylene-thiosemicarbazone based ultrafast, highly sensitive detection of hypochlorite in aqueous environments and dairy products.

We have designed and synthesised a novel fluorescent probe with a tetraphenylethylene (TPE) scaffold as an active fluorescent unit and thiosemicarbazide (TSC) group as a recognition unit. The probe, TPE-TSC, exhibited superior selectivity towards hypochlorite (ClO-) with a low limit of detection (2.0 nM). It also demonstrated a turn-off response for a brief period (<30 s) via an oxidation reaction. Furthermore, high-resolution mass spectrometry (HRMS) revealed that TPE-TSC reacted with ClO- by forming a carboxylic acid moiety in nearly 100% aqueous environments. More significantly, the probe detected ClO- in disinfectant, spiked milk samples, and spiked water samples. In all, TPE-TSC proposes an optimistic approach precisely for the determining the quality of milk and water contaminated with ClO- and trace amounts of ClO- in disinfectants.

Rapid, ultrasensitive, highly selective detection of toxic Hg(II) ions in seabass, swordfish and water samples.

A novel fluorescent probe bearing triphenylamine, thiophene and thiosemicarbazide (TPA-TSC) was developed, and its distinct features were investigated. TPA-TSC demonstrated excellent selectivity towards Hg2+ ions, with a limit of detection (0.14 nM) among the lowest reported to date. It also exhibited a turn-off response by forming stable complex for a brief period (<30 s). Job plot analysis and high-resolution mass spectrometry (HRMS) revealed that TPA-TSC bound to Hg2+ with a 2:1 stoichiometry in an aqueous environment, remarkably the probe successfully detected Hg2+ ions in seabass, swordfish and different samples of water. In all, TPA-TSC offers a promising method for accurately determining the quality of seafood and water samples polluted with Hg2+.

Fluorescein Based Three-channel Probe for the Selective and Sensitive Detection of CO32- Ions in an Aqueous Environment and Real Water Samples.

We have constructed a novel fluorescein-based fluorescent chemosensor, FL-In, functionalised with an indole moiety and capable of sensing by both the optical "turn-on" and electrochemical detection of carbonate ions (CO32-) in aqueous media. The probe exhibits excellent selectivity and a low detection limit (0.27 µM) regarding carbonate ions by a possible coordination and hydrolysis reaction mechanism. The developed probe successfully detected CO32- ions in different samples of water. Also, in a simple filter paper experiment, we documented its ability to allow the monitoring of CO32- with the naked eye.

Oligomer based real-time detection of microorganisms producing nuclease enzymes.

In this study, we provide a method using fluorescently labeled oligonucleotides for the diagnosis of microorganisms producing nucleases in real time, while growing them in culture media. The detection of such microorganisms was possible in a short period of time, as short as 10 minutes up to a maximum of 8 hours, depending on the bacterial density. We also showed the suitability of this new method for determination of minimum inhibitory concentration (MIC) in culture media in a very short period of time, compared to conventional methods. We believe that it can make a significant contribution to gain new insights for analysis of complex materials such as clinical samples, food samples and environmental samples.

Facile syntheses of 3-hydroxyflavones.

Modification of the present synthetic methods led to the syntheses of 3-hydroxyflavones in a shorter reaction time, with simple purification and higher yields. Application of the method provided the syntheses of 3HFs having a hydroxyl group on the phenyl ring (ring B) in one step, which is an improvement compared to the four steps, long reaction time, and low yield using the current method available in the literature.