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[Display omitted] • BPL is a common chemical inactivating reagent used in vaccines. • Via BPL carcinogenicity, its residual should be hydrolyzed completely in vaccines to avoid cytotoxicity. • BPL residual determination in vaccines is challenging due to its low concentration, presence in a complex mixture of vaccine and lack of suitable chromophore. • BPL derivatization with RBH was used to enhance analytical sensitivity and stabilize the BPL molecule for measurement with HPLC-UV. β-propiolactone (BPL) is an alkylating agent used for inactivation of biological samples such as vaccines. Due to its known carcinogenic properties, complete hydrolysis of BPL is essential, and the detection of trace amounts is crucial. In this study a novel High-Performance Liquid Chromatography-Ultraviolet (HPLC-UV) method was developed. Rhodamine B hydrazide (RBH) was synthesized and utilized as a derivatizing reagent to react with BPL. The reaction was optimized in a weak acidic solution, resulting in a high yield. The separation of the RBH-derivatized BPL was achieved on a C8 column and detected by a UV detector at a wavelength of 560 nm. The method's validation demonstrated a high linearity (r2 > 0.99) over a concentration range of 0.5–50 µg/mL, with detection and quantification limits of 0.17 µg/mL and 0.5 µg/mL, respectively. The average recovery of samples was 85.20 % with a relative standard deviation (RSD) of 1.75 %. This method was successfully applied for BPL residue analysis in inactivated COVID-19 vaccines. This novel derivatization method offers a promising solution for monitoring BPL residues in the vaccine production process for quality control purposes and compliance with regulatory standards. [ABSTRACT FROM AUTHOR]

The rational surface functionalization of semiconducting polymer dots (Pdots) has attracted much attention to extend their applications in fabricating chemo/biosensing platform. In this study, a novel ratiometric fluorescent sensing platform using functionalized Pdots as probes for fluorescence signal transmission has been designed for sensing Cu(Ⅱ) and activity of alkaline phosphatase (ALP) with high selectivity and enhanced sensitivity. The highly fluorescent Pdots were firstly prepared with Poly[(9,9-dioctylfluorenyl-2,7-diyl)- co -(1,4-benzo-{2,1′,3}-thiadiazole)] (PFBT) via nanoprecipitation method, and then assembled with non-fluorescent rhodamine B hydrazide (RB-hy), which shows special binding activity to Cu(Ⅱ), through adsorption process to obtain functionalized nanohybrids, Pdots@RB-hy. As thus, a FRET donors/acceptors pair, in which PFBT Pdots act as energy donors while RB-hy-Cu(II) complexes act as energy acceptors were constructed. On the basis of the varies in fluorescence intensities of donors/acceptors in the presence of different amounts of Cu(II), a ratiometric method for sensing Cu(II) has been proposed. The proposed ratiometric Cu(II) sensor shows a good linear detection range from 0.05 to 5 μM with a detection limit of 15 nM. Furthermore, using the Pdots@RB-hy-Cu(II) system as signal transducer, a ratiometric sensing for alkaline phosphatase (ALP) activity has also been established with pyrophosphate (PPi) as substrates. The constructed ratiometric sensor of ALP activity displays a linear detection range from 0.005 to 15 U L −1 with a detection limit of 0.0018 U L −1 . The sensor was further successfully used for ALP activity detection in human serum with satisfactory results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Can select the sensor molecules for the selective recognition of Cu2+ and Fe3+ ions before their synthesis. • The use of chemicals will be controlled in this approach. • The effect of ortho -substituents or heteroatom must play a vital role in selective recognition process. • The mechanism of metal ion recognition was established via theoretically and spectroscopic methods. Herein we have implemented a computational approach in designing sensor molecules for the selective recognition of Cu2+ and Fe3+ ions. Seven rhodamine B hydrazide-based Schiff base derivatives were designed and analysed their chemosensing properties against Cu2+ and Fe3+ ions in ethanol solution theoretically. The theoretical calculations revealed that the selective recognition of Cu2+ and Fe3+ ions takes place via spirolactam ring-opening and there is a pivotal role of ortho substituents and N -heteroatoms. The two best chemosensors were synthesised and used for the detection of Cu2+ and Fe3+ ions by colorimetric methods. [ABSTRACT FROM AUTHOR]

An electrochemical sensor based on gold nanoparticles (Au NPs) modified with rhodamine B hydrazide (RBH) (AuNPs-RBH) was developed and applied in the highly sensitive and selective detection of Cu 2+ in water. RBH molecules were bounded onto the surface of AuNPs via the strong interaction between the amino groups and Au NPs. The chemical structure variations were characterized by X-ray photoelectron spectroscopy and fluoresence spectroscopy. Additionally, electrochemical impedance spectroscopy was used to determine Cu 2+ ions in an aqueous solution with the developed AuNPs-RBH-based electrochemical sensor. Results show that the fabricated sensor exhibits good electrochemical performance because of the presence of Au NPs and high affinity with the Cu 2+ resulting from the strong coordination chemistry between Cu 2+ and RBH. The as-developed sensor towards detecting Cu 2+ has a detection limitation of 12.5 fM within the concentration range of 0.1 pM–1 nM by using the electrochemical impedance technique. It also displays excellent selectivity, regeneration, stability, and practicability for Cu 2+ detection. Therefore, the new strategy of the RBH-based electrochemical sensor exhibits great potential application in environment treatment and protection. [ABSTRACT FROM AUTHOR]

A sensitive, selective and rapid spectrofluorimetric method is proposed for the determination of hydrogen peroxide using rhodamine B hydrazide as a fluorogenic substrate catalyzed by iron(III)-tetrasulfonatophthalocyanine. It is based on the oxidation of rhodamine B hydrazide, a colorless, non-fluorescent spirolactam hydrazide, by hydrogen peroxide which generates the highly fluorescent product rhodamine B. Under optimum conditions, the responses for hydrogen peroxide were linear from 2.0 × 10−8 to 2.0 × 10−6 mol L−1, with a detection limit of 3.7 × 10−9 mol L−1 in a 3.5 min reaction period. It can easily be incorporated into the determination of biochemical substances that produce hydrogen peroxide under catalytic oxidation in the presence of their oxidase. The possibility has been tested for the determination of glucose in human sera as an example. [ABSTRACT FROM AUTHOR]

Rhodamine B hydrazide can be used to detect hydroxyl radicals in plant cells. RBH was easily inserted into plant cells without any pretreatment, and specifically reacted with intracellular hydroxyl radicals produced by antimycin A. RBH will be a powerful tool for detecting hydroxyl radicals in plant cells. [ABSTRACT FROM AUTHOR]

• Rhodamine B hydrazide was proposed as a new derivatizing reagent for formaldehyde. • A rapid, selective and sensitive HPLC method for residual formaldehyde in a drug was developed and validated. • The proposed method has the advantages of mild derivatization temperature, short derivatization time, and high sensitivity. Rhodamine B hydrazide (RBH) was prepared as a new derivatizing reagent for residual formaldehyde in a drug such as N-butyl-2-cyanoacrylate (NBCA). RBH reacted with formaldehyde rapidly at room temperature, and the resulting derivative can be detected sensitively at 238 nm. After optimizing the derivatization and chromatographic separation conditions, RBH as a pre-column derivatizing reagent has been successfully used for the analysis of formaldehyde in real NBCA samples by high-performance liquid chromatography (HPLC). The detection limit of the method is 0.004 μg/mL for formaldehyde, and the recovery is 94.0%-96.6%. Most notably, compared with the previous HPLC methods, the developed method has the advantages of mild derivatization temperature, short derivatization time and high sensitivity. [ABSTRACT FROM AUTHOR]

In this work, different materials were fabricated from cellulose acetate, loaded with rhodamine B hydrazide and tested as Cu(II) optical sensor. We prepared membranes displaying a sub-micron porous structure using the phase inversion technique, clusters of fibers with varying diameter depending on the preparation procedure using electrospinning, and casted films presenting a smooth non porous structure. Loading of rhodamine B hydrazide on the fabrics after their production was found to be the best procedure to ensure the stability of the dye in the polymeric materials. Absorption and emission analysis of the solid substrates revealed the presence of the dye on the porous fabrics and allowed to choose the most suited materials and loading conditions to test their response towards Cu(II) ions. Reaction of the loaded rhodamine B hydrazide with Cu(II) was confirmed by absorption and emission spectroscopies and by confocal fluorescence imaging, through detection of the product rhodamine B. The results point to promising sensing applications of the prepared composite materials. [ABSTRACT FROM AUTHOR]

Polysulfone‐based materials were fabricated as casted films, porous membranes, and nanofibers by solution casting, phase inversion process, and electrospinning technique, respectively. Photoactive rhodamine B hydrazide molecules were loaded into the fabrics either in preloading or postloading processes. The morphological structure of the fabrics was investigated by scanning electron microscopy and the wettability was determined by contact angle measurements. Detailed spectroscopic characterizations of the closed and open forms of rhodamine B was performed both in solution and in the solid‐state composite materials. Theoretical investigations supported the depiction of the absorption and emission features of the two forms. The response of the prepared composite materials to Cu(II) ions has been tested by absorption and emission spectroscopy and confocal fluorescence imaging. The most effective materials for Cu(II) detection were found to be polysulfone films prepared by phase inversion and postloaded with 10% rhodamine B hydrazide. These results open the way to the development of composite sensory membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48408. [ABSTRACT FROM AUTHOR]