Phenolphthalein Research Articles

Phycoremediation of Phenolphytalein, Indigo Carmine, Methyl Orange and Eriochrome Black T By Using Chlamydomonas and Chlorella sp. (Chlorophyta)

This work aimed to evaluate the decolorization of phenolphthalein (PP), indigo carmine (IC), methyl orange (MO) and eriochrome black T (EBT) by using Chlorella and Chlamydomonas as a biosorbent. This experiment used the batch adsorption method to study the adsorption effect of pH, biomass dosage, contact time, initial dye concentration and temperature on the dyes. The adsorption of the dyes onto the cells were fitted with the Langmuir and Freundlich isotherms. The results showed that the optimum conditions for PP removal (99%) was obtained at pH 4, contact time of 120min, 35°C, algal dosage of 0.5 mg/mL and dye concentration of 100 mg/L on to the cells. The sample prepared at 25°C, 120 min, 1 mg/mL algal dosage, 25 mg/L dye concentration and at pH 4 had the best adsorption effect on IC on to the both of cells (99-98%). In addition, the optimum conditions for MO and EBT removal (99-97%) was obtained at pH 2-4, contact time of 30 min, 25°C, algal dosage of 0.5mg/mL and dye concentration of 100mg/L. The results of this study reveal that the algae cells can be utilized as an efficient and eco-friendly biosorbent for the removal of the indicator dyes from aqueous solution.

Synthesis, characterization, and thermal pyrolysis mechanism of high temperature resistant phenolphthalein-based poly (arylene ether nitrile)

Phenolphthalein (PP) is usually used as a functional monomer to design novel high performance polymers with adjustable thermal, mechanical, and fluorescent properties. In this study, a soluble, amorphous, high temperature resistant PP-based poly (arylene ether nitrile) (PAEN) was synthesized and its corresponding thermal decomposition mechanism was reported via TGA/DTG, TGA/FTIR and TGA/MS analysis. PP-based PAEN showed a Tg of 250 °C a Tdmax of 503 °C and a char residue of 59.2 % at 800 °C, respectively. According to Kissinger and Flynn–Wall–Ozawa model, the activation energy of thermal pyrolysis was calculated as 225 ± 4 and 284 ± 17 kJ/mol respectively, higher than those of other poly arylene ethers. PP-based PAEN showed a three-stage thermal pyrolysis mechanism. Its initial degradation happened before 400 °C and liberated the inherent moisture. The latter backbone decomposition between 400 and 600 °C involved multiple routes mainly from the CO and CC cleavages of lactone ring, resulting in a Ph2CHPhOPh intermediate by releasing HCHO, HCOOH, CO2, H2O, CH4, C6H6, and C6H5OH. The third carbonization stage over 600 °C included the transformation from biphenyl linkages to aromatic graphite by dehydrogenation. This study not only gives a comprehensive understanding of the thermal pyrolysis behavior of PP-based PAEN, but also provides valuable references for the thermal behaviors of other PP-containing polymers.

Highly Permeable Ultrafiltration Membranes Based on Polyphenylene Sulfone with Cardo Fragments.

For the first time, copolymers of polyphenylene sulfone (PPSU) with cardo fragments of phenolphthalein (PP) were synthesized to develop highly permeable flat-sheet ultrafiltration membranes. By introducing cardo fragments into the polymer chain, we achieved a mechanical strength 1.3 times higher than the strength of commercial PPSU. It is shown that the introduction of the cardo monomer significantly increases the solubility of the polymer in aprotic solvents. The highest solubility is observed at the concentration of PP 50 mol.%. It is found that reduced viscosity of cardo polymer solutions leads to an increase in the coagulation rate. The permeance of asymmetric ultrafiltration membranes increases with PP concentration from 17.5 L/(m2·h·bar) (10 mol.% PP) to 85.2 L/(m2·h·bar) (90 mol.% PP). These data are in agreement with the results of a study of the coagulation rate of polymer solutions. Thus, for ultrafiltration membranes with 1.5-8 times higher permeance in comparison with PPSU due to the introduction of cardo fragments in the polymer chain, possessing high rejection of the model dye Blue Dextran (MW = 70,000 g/mol), more than 99.2%, as well as high strength characteristics, were achieved.

Visual authenticating hazardous adulterant phenolphthalein in slimming foods: Target-mimicking hapten epitope improved immunoassay

Screening for the hazardous adulterant phenolphthalein (PTH) in slimming foods is necessary. Herein, the linkage of the PTH target epitope with various spacer arms was proposed for hapten design, aiming to produce highly sensitive and specific antibodies targeting PTH. To understand the influence of spacer arms on epitope, comprehensive evaluations were conducted using computer-aided chemistry and animal immunization. The resulting antibody exhibited maximal half-inhibitory concentration (IC50) of 0.25 ng/mL. Then, a lateral flow immunoassay (LFIA) was established with detection capability for screening (CCβ) of less than 140, 240, and 25 ng/g for PTH in tea, instant coffee, and oral liquid, respectively. Furthermore, blind sample results agreed well with LFIA and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Therefore, this work not only provides a robust tool for detecting PTH adulteration but also suggests that the careful pairing of spacer arms with hapten epitope is a key factor in advancing rational hapten design.

Synthesis and properties of phenolphthalein‐based thermoplastic poly(ether nitrile imide)s via aromatic nucleophilic substitution polymerization

AbstractAromatic nucleophilic substitution polymerization was used to synthesize five poly(ether nitrile imide)s (PENIs) that include benzonitrile and bulky cardo groups from a mixture of phenolphthalein (PP), 4,4′‐bis(4‐fluorophthalimide) diphenyl ether (4,4′‐BFPI), and 2,6‐difluorobenzonitrile (DFBN). The structure and properties relationship of PENIs with different ratios of DFBN and 4,4′‐BFPI was explored. It was found that the glass transition temperature (Tg) of PENIs decreased from 280 to 260°C, while the temperature of 5% thermal weight loss (T5%) in N2 increased from 429 to 453°C as the benzonitrile content in PENI increased. The produced PENI films had good mechanical characteristics, including tensile strengths of 103–112 MPa, elongations at break of 5.6%–8.2%, and tensile moduli of 2.9–3.4 GPa. Furthermore, the solubility and melt processability were also improved with the introduction of the benzonitrile group. Compared with poly(ether ketone imide)s (PEKIs) and poly(ether sulfone imide)s (PESIs), PENIs with benzonitrile displayed higher Tg, tensile modules, and lower complex viscosity.

Probiotic potential of Lacticaseibacillus rhamnosus VHProbi M15 on sucralfate-induced constipation in mice

The main objective of this study was to investigate the potential probiotic properties of Lacticaseibacillus rhamnosus VHProbi®M15 (M15). This study examined the effects of M15 on sucralfate-induced constipation in a mouse model. The BALB/c mice were randomly divided into four groups: the normal group (NOR) was without any treatment, while the constipation (CON), phenolphthalein (PHE), and probiotic (PRO) treatment groups were fed with sucralfate until the appearance of constipation symptoms. Afterward, the NOR and CON groups were given 1 ml saline orally every day until the end of the experiment; the PHE and PRO groups were given phenolphthalein or M15 suspension in 1 ml orally, respectively. Compared with the CON group, the fecal water content and intestinal peristalsis improved in the PRO group. Here, intake of M15 effectively attenuated sucralfate-induced constipation, recuperated colonic epithelial integrity, and increased serum levels of gastrointestinal excitatory neurotransmitters (motilin, gastrin, substance P). Analysis of the intestinal microbiota of mice by 16S rRNA metagenomic revealed an increase in the relative abundance of Bacteroides and a decrease in Sclerotinia, Verrucosa and Proteus in the PRO group. Compared with the CON group, the constipation-induced intestinal microecological changes were partially recovered in the PHE and PRO groups. These results demonstrate that M15 enhanced gastrointestinal transit and alleviated in mice with sucralfate-induced constipation.

Increased Endocrine Activity of Xenobiotic Chemicals as Mediated by Metabolic Activation.

The US Environmental Protection Agency (USEPA) is faced with long lists of chemicals that require hazard assessment. The present study is part of a larger effort to develop in vitro assays and quantitative structure-activity relationships applicable to untested chemicals on USEPA inventories through study of estrogen receptor (ER) binding and estrogen-mediated gene expression in fish. The present effort investigates metabolic activation of chemicals resulting in increased estrogenicity. Phenolphthalin (PLIN) was shown not to bind rainbow trout (Oncorhynchus mykiss) ER (rtER) in a competitive binding assay, but vitellogenin (Vtg) expression was induced in trout liver slices exposed to 10-4 and 10-3.7 M PLIN. Phenolphthalein (PLEIN), a metabolite of PLIN, was subsequently determined to be formed when slices were exposed to PLIN. It binds rtER with a relative binding affinity to 17β-estradiol of 0.020%. Slices exposed to PLEIN expressed Vtg messenger RNA (mRNA) at 10-4.3 , 10-4 , and 10-3.7 M, with no detectable PLIN present. Thus, Vtg expression noted in PLIN slice exposures was explained by metabolism to PLEIN in trout liver slices. A second model chemical, 4,4'-methylenedianiline (MDA), was not shown to bind rtER but did induce Vtg mRNA production in tissue slices at 10-4.3 , 10-4 , and 10-3.7 M in amounts nearly equal to reference estradiol induction, thus indicating metabolic activation of MDA. A series of experiments were performed to identify a potential metabolite responsible for the observed increase in activity. Potential metabolites hydroxylamine-MDA, nitroso-MDA, azo-MDA, and azoxy-MDA were not observed. However, acetylated MDA was observed and tested in both ER-binding and tissue slice Vtg induction assays. Environ Toxicol Chem 2023;42:2747-2757. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Immobilization of β-cyclodextrin onto the surface of electrospun fibers as rapid and highly efficient adsorbent with good recyclability

It is still a big challenge to obtain adsorbents with high adsorption rate and improved adsorption capacity. Herein, we report a novel electrospun fibers adsorbent modified with carboxylated-β-cyclodextrin (CB-β-CD) molecules for the rapid and efficient removal of phenolphthalein (PHP) from water. First, CB-β-CD is synthesized by esterification of β-CD with succinic anhydride. Subsequently, by means of polydopamine (PDA) coating rich in amine groups, CB-β-CD is covalently bonded onto the surface of poly(vinylidene fluoride)@polystyrene/PDA (PVDF@PS/PDA) fibers through the amide linkage to obtain PVDF@PS/PDA/CB-β-CD fibers adsorbent. XPS, WCA and thermal properties results suggest that large amounts of CB-β-CD molecules hang over the surface of PVDF@PS/PDA/CB-β-CD fibers and the cavities of CB-β-CD molecules are well preserved, thus providing more sites to form inclusion complexes with guest molecules. The adsorbent exhibits excellent adsorption properties for PHP, with a saturation adsorption capacity of 39.97 mg/g after 10 min, which is superior to other reported adsorbents containing β-CD. Moreover, PVDF@PS/PDA/CB-β-CD shows good recyclability and highly selective adsorption of PHP, which has potential applications in molecular recognition, organic molecules separation, and water purification. The developed method provides a new strategy for immobilizing more β-CD molecules onto the surface of composite materials to endow superior comprehensive performances.

Preparation and application of nickel copper ferrate and its metal–organic framework composite in the decontamination of chemical indicator contaminated synthetic and raw laboratory wastewater

Inefficient decontamination of laboratory wastewater polluted by chemical indicators such as methyl orange (MO) and phenolphthalein (PH) is a challenge that requires attention in most developing countries. In response to this, nickel-copper ferrate (NiCuFeO4) and nickel-copper ferrate-terephthalic acid-zinc metal–organic framework composite (NiCuFeO4@MOF-5) were synthesised via simple chemical process and their activities compared for the removal of MO and PH from synthetic and raw laboratory wastewater colleccted from a science laboratory at Federal Polytechnic, Ede, Nigeria. The scanning electron micrograph (SEM) images, revealed the surfaces of NiCuFeO4 and NiCuFeO4@MOF-5 to be rough and homogeneous with tightly arranged particles that are agglomerated. The adsorption capacity of NiCuFeO4@MOF-5 expressed for the removal of MO (30.97 mg g−1) and PH (41.22 mg g−1) from aqueous solution is higher than that of NiCuFeO4 for MO (25.82 mg g−1) and PH (23.00 mg g−1). NiCuFeO4 and NiCuFeO4@MOF-5 exhibited a promising stability even at the 7th regeneration cycle for the removal of MO and PH from solution. Results obtained for the removal of MO and PH from aqueous solution by NiCuFeO4 and NiCuFeO4@MOF-5 compared favorably with reported adsorbents in literature. Conclusively, NiCuFeO4@MOF-5 is a potential and better adsorbent than NiCuFeO4 for decontaminating laboratory wastewater contaminated with MO and PH.

Enhanced drug carrier capacity after post modification process for amino acid substitute phosphazene based microspheres with anticancer activity

In this study, drug carrier HCCP-PP-LEEMP microspheres were synthesized by using Hexachlorocyclotriphosphazene (HCCP), Phenolphthalein (PP) and l-Lysine Ethyl Ester Dihydrochloride (LEE) by polycondensation reaction. The synthesized spheres were modified in an acidic environment, and a cationic charge was formed on their surfaces. Synthesized and quaternized microspheres were characterized using FT-IR, SEM, TEM, TGA and Zeta (ζ) potentials analyzes. HCCP-PP-LEE-ATA-QMP microspheres with increased anionic drug carrying capacity as a result of quaternization were used as carriers for Sodium Diclofenac (NaDc) and Cimetidine drugs. While the unmodified HCCP-PP-LEEMP microspheres did not retain the NaDc drug, the NaDc drug retention capacity of the quaternized HCCP-PP-LEE-ATA-QMP microspheres was calculated as 99.6677 mg/g. Thus, it was determined that the drug holding capacity of the microspheres could be increased tens of times compared to their initial state, thanks to the positive charges formed on the surface of the drug carrier microspheres as a result of quaternization. At the same time, Cimetidine, a type of chemotherapeutic drug, was loaded into the microsphere using as drug delivery system. In vitro drug release behaviors of the developed phosphazene and amino acid-based delivery system were investigated and drug release kinetic models were determined. In addition, the antibacterial and antifungal effects of the microspheres were investigated with the effect of LEE in the structure of the microspheres. Then, the anticancer behavior of the cimetidine-loaded microspheres was tested on HT-29 colon cancer cell lines. Thus, a potential carrier system that can carry drugs for the treatment of a selective disease or chemotherapeutics for the treatment of cancer has been synthesized.

COMPARISON OF ACID NUMBERS IN BULK AND PACKAGED COOKING OIL SAMPLES

Palm cooking oil is a food ingredient with a main composition of triglycerides, with or without chemical changes. The amount of free fatty acids determines the quality of cooking oil, which can have bad effects on humans. This study aims to determine the quality of oil in packaged cooking oil and bulk cooking oil with treatments based on acid number, acid content, and degree of acidity. Commercial and bulk packaged cooking oils were used in this study. This research method uses acid-base titration with phenolphthalein (PP) as an indicator. The results of this study indicate that the ingredients of bulk cooking oil and packaged cooking oil, when determining the acid number and free fatty acid content, meet the quality standards of SNI 01-3741-2013, namely each acid number 0.6 mg KOH/g and acid content 0.3%.

The Effect of Alkali Iodide Salts in the Inclusion Process of Phenolphthalein in β-Cyclodextrin: A Spectroscopic and Theoretical Study.

The formation of the inclusion complex between β-cyclodextrin (CD) and phenolphthalein (PP) was investigated by means of UV-Vis and FT-IR spectroscopies. The thermodynamic parameters were calculated in the absence and presence of LiI, KI, NaI and CsI iodide salts. The enthalpy change during the formation was found to be negative for all solutions with iodide salts. The enthalpy change was found to decrease in the sequence no salt > NaI > KI> CsI > LiI. Moreover, it was observed that with increasing salt concentration enthalpy decreases monotonically. The interaction between the two molecules was mostly attributed to hydrogen bonding and Van der Waals interactions. Thermodynamic properties revealed that electrostatic forces also contribute when LiI is present in solutions. A molecular docking study was performed to elucidate the docking between phenolphthalein and cyclodextrin. The FT-IR spectra of CD, PP and the CD-PP complex were recorded to establish the formation of the inclusion complex. Semi-empirical and DFT methods were utilized to study theoretically the complexation process and calculate the IR vibrational spectra. The adequate agreement between theoretical and experimental results supports the proposed structural model for the CD-PP complexation.

Synthesis and characterization of amorphous fluorinated polyarylether prepared from phenolphthalein and decafluorobiphenyl

AbstractPoly(arylene ether)s with different molecular weights were synthesized via a two‐step nucleophilic substitution polymerization by adjusting reaction parameters based on phenolphthalein (PHT) and decafluorobiphenyl (DFBP). The chemical structures and properties were identified by Fourier transform infrared, NMR, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, dynamic thermomechanical analysis (DMA), and so forth. The number‐average molecular weight (Mn) of the resulting polymers was in the range of 23.0–49.3KDa. FPAEs (polyarylether including perfluorobiphenyl structure) were demonstrated to have outstanding thermo‐resistance with 5% weight loss temperature of about 482–520°C (N2) and high‐glass transition temperature (about 240–250°C). FPAEs can be dissolved in conventional organic solvents, possessing excellent film‐forming properties. The good mechanical properties of FPAEs were confirmed by the DMA data, with Young's modulus greater than 1.0 Gpa and modulus retention rate at 230°C >67%. FPAEs also showed good hydrophobicity and low‐water absorption, in particular, FPAE‐1 (FPAE‐1‐5 were the polycondensation products of PHT and DFBP, just the polymerization conditions were slightly modified) exhibited favorable dielectric properties: at 1 MHz, the dielectric constant and dielectric loss was 2.58 and 0.0053, respectively. Thus, FPAE‐1 has broad prospective applications in microelectronic devices and communication technology.

Extraction-free techniques for sensitive detection of a petroleum marker on a paper-based platform

Fuel adulteration and cross-contamination lead to low-quality fuel products and loss of taxes. It is essential to develop methods of marking, identifying and monitoring tax classification of petroleum products in the market. In this work, a method for sensitive and fast detection of gasoline marker using paper-based platform and a smartphone camera detection are developed. A common dye, phenolphthalein (PhP), is used as a colorless dye marker in commercial gasoline. The color was developed by the interaction of PhP with NaOH on filter paper strips and evaluated by CMYK color systems. The newly developed counter-flowing technique, in which a gasoline sample containing PhP and NaOH solution are allowed to travel on a filter paper strip from the opposite end, gives the naked eye detection of PhP as low as 1 ppm with the limit of detection for a smartphone camera of 0.31 ppm. The high sensitivity is attributed to the preconcentration derived from accumulation of PhP at the immiscible liquid interface. The counter-flowing method can thus be a new facile analytical technique for enhancing chemical detection sensitivity.

Polypyrrole-polyaniline nanorods assisted electromembrane extraction of phenolphthalein from herbal slimming products prior to its determination by the liquid chromatography method

Herein, polypyrrole-polyaniline nanorods (PPy-PANI NRs) were synthesized via oxidative polymerization and subsequently were used in electromembrane extraction of phenolphthalein from herbal slimming products. The copolymer was added to the supported liquid membrane to enhance the extraction efficiency of phenolphthalein (PP), and then the analyte was determined by a liquid chromatography-ultraviolet detection system. This is the first report on the application of PPy-PANI NRs as an additive in the electromembrane extraction method. The PP can interact with the PPy-PANI NRs material via interactions such as ion exchange, electrostatics, π-π, and hydrogen bonding. Accordingly, an enhancment in extraction performance was observed in the presence of PPy-PANI NRs as the SLM modifier. The optimized extraction conditions were: donor phase pH, 8.2; acceptor phase pH, 12.0; extraction time, 14 min; voltage, 30 V; stirring rate, 750 rpm; PPy-PANI NRs concentration in the SLM, 1.0 mg mL−1; and 1-octanol as the extraction solvent. A wide linear range and low detection limit equal to 3.0–2000, and 1.0 μg L−1 were obtained, respectively. Besides, the excellent clean-up was attended, which is a great advantage over the more sample preparation methods. Finally, the new method was successfully used to determine PP in slimming products of Iranian markets, and satisfactory results (5.5–8.5 % RSDs; relative recovery, 80–110 %) were obtained.

Fully bio-based supramolecular gel based on cellulose nanowhisker gallate by cyclodextrin host-guest chemistry

Nowadays, supramolecular hydrogels have gained special importance and development of versatile approaches for their preparation as well as their new facile characterization strategies has elicited tremendous scientific interest. Herein, we demonstrate that modified cellulose nanowhisker with gallic acid pendant groups (CNW-GA) could effectively bind with CNW grafted with β-Cyclodextrin (CNW-g-β-CD) through HG interaction to form fully biocompatible and low-cost supramolecular hydrogel. Also, we reported an easy and efficient colorimetric characterization method for confirming HG complexation using naked eye. The possibility of this characterization strategy evaluated both experimentally and theoretically using DFT method. Also, phenolphthalein (PP) was used for visual detection of HG complexation. Interestingly, PP undergoes a rearrangement in its structure in presence of CNW-g-β-CD because of HG complexation that turns the purple molecule into a colorless compound in alkaline condition. Addition of CNW-GA to the resulting colorless solution turned the color to purple again which easily confirmed HG formation.

Permeation of Hydroxypropyl-Beta-Cyclodextrin and Its Inclusion Complex Through Mouse Small Intestine Determined by Spectrophotometry

Background: Cyclodextrins (CDs) are commonly used host molecules of inclusion complex. However, due to the lack of a sensitive determination method, the absorption process of CDs remains unclear. Objective: In this study, an oleuropein (OL) inclusion complex employing hydroxylpropyl-betacyclodextrin (HP-beta-CD) as host molecules was prepared and the formation of inclusion complex was ascertained by FT-IR and DSC. Spectrophotometry was established for the determination of HP-beta-CD, based on the fact that the absorbance of phenolphthalein (PP) decreased in the presence of HP-beta-CD. Methods: The assay conditions were optimized to augment the method sensitivity. Molecular docking was employed to verify the strong interaction between PP and HP-beta-CD. The permeation process of free HP-beta-CD, HP-beta-CD of OL inclusion complex, free OL, and OL in the inclusion complex, was examined using an in vitro mouse small intestine model. Results: Though HP-beta-CD possessed a hydrophilic outside shell, it could permeate through the mouse small intestine quickly with a cumulative permeating amount of over 90% in 2 h. Free HPbeta- CD, the host molecule HP-beta-CD, and guest molecule OL of the inclusion complex exhibited consistent permeating profiles across the mouse small intestine. Conclusion: The approach for the determination of HP-beta-CD was accurate and precise (%RSD=2.98).

Removal of phenolphthalein and methyl orange from laboratory wastewater using tetraethylammonium modified kaolinite clay

Developing an efficient technique for the treatment of laboratory wastewater is a challenge. In response, kaolinite clay (CLY) was functionalized with tetraethylammonium bromide to produce tetraethylammonium modified kaolinite clay (CLY@AM). Both CLY and CLY@AM were characterized with X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). CLY and CLY@AM were evaluated for their ability to remove phenolphthalein (PH) and methyl orange (MO) from laboratory wastewater. Peaks from FTIR and XRD suggests the formation of CLY@AM, while SEM micrograph revealed the surfaces of CLY and CLY@AM to be irregularly shaped while CLY@AM has some patches. The adsorption capacities exhibited by CLY@AM towards PH (43.00 ​mg ​g−1) and MO (40.00 ​mg ​g−1) were found more promising compared to CLY, which showed 20.00 and 22.00 ​mg ​g−1 towards MO and PH, respectively. The ΔHo value for the sorption of PH was found to be −71.7523 ​kJ ​mol−1, while the value was −46.1826 ​kJ ​mol−1 for MO. The ΔHo values are negative in nature which suggests the process to be exothermic. The removal of MO and PH from the solution may be described by Langmuir isotherm with a regeneration capacity above 80% even at the 14th regeneration cycle. Applying CLY@AM towards the purification of raw laboratory wastewater contaminated with PH and MO further proves the effectiveness of CLAY@AM as a potentially efficient material for the purification of laboratory wastewater systems contaminated with PH and MO.

Bendable poly(vinylidene fluoride)/polydopamine/β-cyclodextrin composite electrospun membranes for highly efficient and bidirectional adsorption of cation and anion dyes from aqueous media

Electrospun fibrous membranes have potential application prospects in various adsorbents. However, challenges remain in the development of flexible adsorbents with multiple adsorption ability and improved efficiency. In this study, we design and fabricate a new class of composite electrospun membranes poly(vinylidene fluoride)/polydopamine/β-cyclodextrin (PVDF/PDA/β-CD) by triggering the self-polymerization of dopamine onto the surface of PVDF electrospun fibers to form PDA coating, and subsequently binding β-CD molecules on the fibers surface via hydrogen bonding as the result of hydroxyl groups on β-CD and abundant catechol groups of PDA. The PVDF/PDA/β-CD fibers exhibit core-shell structure where PVDF as the supporting core component and PDA/β-CD layer as the shell with many functional groups to be capable of adsorbing cationic and anionic dye molecules. Accordingly, the composite membranes possess highly efficient adsorption performance toward methylene blue (MB) and phenolphthalein (PHP). Furthermore, the adsorption behaviors for the two dyes fit well with the pseudo second-order kinetic model. And the electrostatic attraction and π-π stacking mostly promote the adsorption of MB whereas the host-guest inclusion complexation and hydrogen bonding are more likely to favor the PHP adsorption. Most importantly, all composite membranes can be bendable, and display excellent mechanical performances, which endow these membranes easy to operate in practical applications, such as filtration, separation and purification purposes. Our developed method provides a new avenue for electrospun membrane to simultaneously achieve robust mechanical properties and multiple contaminants efficient removal.

Validation of the method for determination of Phenolphthalein and Sibutramine in weight‐loss functional foods from Viet Nam by UPLC‐MS/MS

AbstractA rapid, selective, and sensitive method by using ultra‐performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS) for the simultaneous determination of phenolphthalein (PP) and sibutramine (SB) in weight‐loss functional foods was developed. The optimal conditions of liquid chromatographic separation and mass spectroscopy of PP and SB have also been examined. The linear ranges for both PP and SB detected by the method were 0.20÷10.0 ng/mL, and corresponding correlation coefficients of 0.9991 and 0.9992, respectively. Mean recoveries of both analytes in the weight‐loss functional foods at three spike levels (low, medium, and high) were within the range of 98.5÷102.5 % (n = 11). LOD, LOQ values of PP were 0.12 and 0.36 ng/mL, respectively, while SB's LOD and LOQ were 0.09 ng/mL and 0.28 ng/mL. The impact of the matrix effect on the accuracy, repeatability, and recovery of the process was negligible. The recommended approach was applied to determine the content of the two substances in ten weight‐loss drug capsules and nine weight‐loss herbal teas, which were purchased in Ho Chi Minh City Viet Nam in 2019. PP was found in 5 of 19 samples, and SB was detected in 6 of 19 samples.