A Reaction-Based Novel Fluorescent Probe for Detection of Hydrogen Sulfide and Its Application in Wine

Activity-Based Fluorescent Probes for Hydrogen Sulfide and Related Reactive Sulfur Species

Hydrogen sulfide (H2S) is not only a well-established toxic gas but also an important small molecule bioregulator in all kingdoms of life. In contemporary biology, H2S is often classified as a "gasotransmitter," meaning that it is an endogenously produced membrane permeable gas that carries out essential cellular processes. Fluorescent probes for H2S and related reactive sulfur species (RSS) detection provide an important cornerstone for investigating the multifaceted roles of these important small molecules in complex biological systems. A now common approach to develop such tools is to develop "activity-based probes" that couple a specific H2S-mediated chemical reaction to a fluorescent output. This Review covers the different types of such probes and also highlights the chemical mechanisms by which each probe type is activated by specific RSS. Common examples include reduction of oxidized nitrogen motifs, disulfide exchange, electrophilic reactions, metal precipitation, and metal coordination. In addition, we also outline complementary activity-based probes for imaging reductant-labile and sulfane sulfur species, including persulfides and polysulfides. For probes highlighted in this Review, we focus on small molecule systems with demonstrated compatibility in cellular systems or related applications. Building from breadth of reported activity-based strategies and application, we also highlight key unmet challenges and future opportunities for advancing activity-based probes for H2S and related RSS.

Rational synthesis of 1,3,4-thiadiazole based ESIPT-fluorescent probe for detection of Cu2+ and H2S in herbs, wine and fruits

Here, 1,3,4-thiadiazole unit was employed as novel excited state intramolecular proton transfer (ESIPT) structure to prepare favorable fluorescent probe. High selectivity and rapid response to Cu2+ was obtained and the settling reaction was also used to recover ESIPT characteristics of probe to achieve sequential detection of H2S. Remarkable color change of solution from colorless to bright yellow and fluorescence emission from green to dark realized the visual detection of Cu2+ by naked eyes and transition of probe into portable fluorescent test strips. As expected, L-E could be utilized to quantitatively sense Cu2+ and H2S in different actual water and food samples including herbs, wine and fruits. The limits of detection for Cu2+ and H2S were as low as 34.5 nM and 38.6 nM. Also, probe L-E achieved real-time, portable, on-site quantitative detection of Cu2+ via a colorimeter and a smartphone platform with limit of detection to 90.3 nM.

Current State of Sensors and Sensing Systems Utilized in Beer Analysis

Beer is one of the most consumed beverages in the world. Advances in instrumental techniques have allowed the analysis and characterization of a large number of beers. However, review studies that outline the methodologies used in beer characterization are scarce. Herein, a systematic review investigating the molecular targets and sensometric techniques in beer characterization was performed following the PRISMA protocol. The study reviewed 270 articles related to beer analysis in order to provide a comprehensive summary of the recent advances in beer analysis, including methods using sensors and sensing systems. The results revealed the use of various techniques that include several technologies, such as nanotechnology and electronics, often combined with scientific data analysis tools. To our knowledge, this study is the first of its kind and provides the reader with a faithful overview of what has been done in the sensor field regarding beer characterization.

Growth studies of dominant lactic acid bacteria in orange juice and selection of strains to ferment citric fruit juices with probiotic potential

The study aimed to evaluate the ability of dominant lactic acid bacteria (LAB) in orange juice to growth on N-depleted MRS medium supplemented or not with cysteine (mMRS), then to select the most nutritionally promising strains for growth assays in the food matrix and evaluation of beneficial attributes for fruit juice fermentation. Levilactobacillus brevis and Lactiplantibacillus plantarum were dominant species among the total of 103 LAB isolates as confirmed by multiplex PCR and/or 16 s rDNA sequence analysis. Based on growing lower than 20% and higher than 70% in mMRS (1.0 g/l meat extract, without peptone and yeast extract) with and without cysteine requirement, one L. brevis (JNB23) and two L. plantarum (JNB21 and JNB25) were selected. These bacteria and the L. plantarum strains N4 and N8 (previously isolated from oranges peel) when inoculated in orange juice grew up to 1.0 log cfu/ml for 24 h incubation at 30 °C and mainly produced lactic acid, with strains JNB25 and JNB23 reaching the highest and lowest cell densities in agreement with their nutritional exigency. In addition, all L. plantarum strains exhibited antagonistic activity against the majority of tested bacterial pathogens (in opposition to L. brevis), ability to grow or survive to pH 3.0 for 3 h, to grow with 0.5% sodium taurocholate, and a decrease after simulated gastrointestinal digestion assay which did not exceed 1.0 or 2.0 log units, depending on the strain. Thus, autochthonous L. plantarum strains with ability for overcoming nutritional limitations and beneficial attributes are promising candidates for further investigations as novel probiotic and/or preservative starters to ferment citric fruit juices.

Mitochondria-Targeted Red-Emission Fluorescent Probe for Ultrafast Detection of H2S in Food and Its Bioimaging Application

Hydrogen sulfide (H₂S) contributes to human health and prolongs the storage time of postharvest fruits and vegetables. At the same time, H₂S can cause a negative impact on some foodstuffs and beverages, so an efficient probe to detect H₂S is needed. Herein, a fluorescent turn-on responding probe SPy-DNs for H₂S detection has been designed and synthesized. SPy-DNs exhibited a red emission (608 nm), large Stokes shift (111 nm), and a detection limit of a nanomolar level (356 nM) in a dimethylformamide/phosphate-buffered saline (DMF/PBS) (1:1, v/v, 10 mM, pH 7.4) solution. SPy-DNs can detect H₂S with ultrafast response within 4 s, which is faster than the response of other reported probes. In addition, the applicability of SPy-DNs to detect H₂S has been determined in the actual water samples, targeted mitochondria, and imaged H₂S in living cells. Moreover, SPy-DNs was successfully used as a tool to judge H₂S levels in beer, which indicates that SPy-DNs possesses the advantage of rapid detection of H₂S in foodstuffs.

The recent advance of organic fluorescent probe rapid detection for common substances in beverages

The beverage industry is confronted with tremendous challenges in terms of quality assurance. The allowed contents of common ingredients such as copper ions, hydrogen sulfide, cysteine and caffeine are stipulated by various governing bodies, and the beverage industry must ensure that it meets these requirements. Due to its unique advantages of high sensitivity, low cost and relatively low toxicity over high-performance liquid chromatography, atomic absorption spectrometry and nanomaterials, the use of organic fluorescent probes for the rapid detection of beverage contents has become a hot research topic. This review summarizes the detection of common substances in wine, tea, mineral water, milk and other beverages. Furthermore, the preparation of test paper and simple colour comparison are discussed to display the rapid qualitative capability of designed probes. To improve the current state of beverage safety, future trends and strategies for fast organic fluorescent probe detection in the beverage industry are also discussed.

Determination of Hydrogen Sulfide in Wines Based on Chemical-Derivatization-Triggered Aggregation-Induced Emission by High-Performance Liquid Chromatography with Fluorescence Detection

A chemical-derivatization-triggered aggregation-induced emission (AIE) method for the highly selective determination of hydrogen sulfide (H₂S) in wine matrices by high-performance liquid chromatography with fluorescence detection (HPLC-FLD) was developed. The detection strategy was developed based on the chemical derivatization of H₂S using a low-cost AIE-active fluorescence derivatization reagent, N-(3-iodine-2-oxopropyl)pyrene methamine (NIPM), to trigger specific AIE at 475 nm, which was red-shifted sharply to the maximum emission wavelength as compared with NIPM monomers of 375 nm, effectively quenching the interference from other thiol-containing compounds. With the aid of specific AIE and the effective separation of HPLC, the proposed method showed high selectivity and sensitivity toward H₂S. The limits of detection (LODs) at the sub-nM level of 0.25 nmol/L in the wine-beer sample and 0.30 nmol/L in red wine sample were obtained. To certify its applicability, this proposed strategy was successfully applied for the determination of H₂S in wine matrices.

The synthesis and bioimaging of a biocompatible hydrogen sulfide fluorescent probe with high sensitivity and selectivity

Hydrogen sulfide (H₂S), a well-known poisonous gas, has been recognized as a critical endogenous gas transmitter in the past decade.

Dual-Function Fluorescent Probe for Detection of Hydrogen Sulfide and Water Content in Dimethyl Sulfoxide

To detect hydrogen sulfide (H2S) and water content in dimethyl sulfoxide, the fluorescent probe (Probe 1) was used, as it not only detects H2S but also detects the water content. After H2S was added into Probe 1, the intensity of fluorescence increased and was up to 1300 times. In case the H2S concentration was in the range 0-20 μM, it was able to be detected by Probe 1, and the limit of detection was 0.851 nM. When Probe 1 and H2S underwent a reaction, the solution color had some changes. These colors changed in terms of the concentration changes of H2S, ranging from colorless to yellow. The Probe 1 test paper only needed to be exposed to hydrogen sulfide gas for 20 s for the color change to occur. Besides, Probe 1-H2S was used to detect water content in dimethyl sulfoxide which ranged from 0 to 100%. The color change of the solution was opposite to that of H2S, ranging from yellow to colorless.