Fast and efficient immunoaffinity column cleanup and liquid chromatography–tandem mass spectrometry method for the quantitative analysis of aflatoxins in baby food and feeds

An ultra high performance liquid chromatography‐tandem mass spectrometric method has been developed for the highly sensitive and selective determination of regulated aflatoxins. The extraction of aflatoxins from baby food matrices were performed using liquid–liquid extraction procedure followed by immunoaffinity column cleanup. The higher sensitivity for the determination of target aflatoxins was fulfilled by applying a preconcentration step with immunoaffinity columns after acetonitrile–water extraction. The enhanced selectivity was attained with the triple quadrupole mass analyzer operated in electrospray positive ionization mode. Method validation was tested in five different baby food matrices by recovery experiments. Satisfactory recoveries, between 92 and 103%, with relative standard deviations lower than 8% were achieved in all the tested matrices. The proposed method was found to be specific as no interference peaks were observed for blank samples. The limit of detection of the method was found to be in the range of 0.003–0.008 ng/mL. The validated method was fruitfully applied to the screening of aflatoxins in baby foods and feeds sample retailed in local markets of Riyadh, Saudi Arabia. The obtained levels of all analyzed aflatoxins were below the regulation limits set by European Agency.     

Spectrofluorimetric determination of fexofenadine hydrochloride in pharmaceutical preparation using silver nanoparticles

A novel sensitive fluorimetric method was investigated for the assay of fexofenadine hydrochloride (FEX) using silver nanoparticles (NPs) as a fluorescence probe. The NPs, which were prepared by chemical reduction of silver nitrate with sodium borohydride (reducing agent) in aqueous solution (without organic stabilizers) were water soluble, stable and had narrow emission band. The addition of drug to NPs solution caused considerable quenching of the emission band of silver NPs, which was likely due to the complexation of the drug to silver NPs. Under the optimum conditions, the quenched fluorescence (FL) intensity was linear with the concentration of FEX in the range of 1 × 10^?7 to 2.5 × 10^?5 mol L^?1 (0.9985) with a detection limit of 1.2 × 10^?8 mol L^?1. The quenching mechanism of the studied drug on the emission band of silver NPs was explained by Stern–Volmer law. The developed method was applied to FEX determination in a pharmaceutical formulation (allegra tablets) and biological fluids (human serum and urine).     

Rapid crystallization of amorphous silicon utilizing a radio-frequency thermal plasma torch

The rapid crystallization of amorphous silicon utilizing the radio-frequency (rf) inductive coupling thermal plasma torch of argon is demonstrated. Highly-crystallized Si films were fabricated on thermally grown (th-)SiO₂ and textured a-Si:H:B/SnO₂/glass by adjusting a distance between the tip of the silica tube and the substrate stage and the translational velocity of the substrate stage. The crystallization was promoted efficiently from the bottom to front surface during the solidification and crystallization of liquid Si.     

A new synthesis of flavones and pyranoflavone by intramolecular photochemical Wittig reaction in water

A new synthetic approach toward the synthesis of flavones and pyranoflavone has been developed by light induced intramolecularphotochemicalWittigreaction in water onto aryloxycarbonyl groups and suitably substituted phosphonium bromides sans any phase transfer catalyst or promoter.     

Analysis of aflatoxins in nonalcoholic beer using liquid–liquid extraction and ultraperformance LC‐MS/MS

Aflatoxins AFB1, AFB2, AFG1, and AFG2 are toxic secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus and posses a potential threat to food safety. In the present work, liquid–liquid extraction and ultraperformance LC‐MS/MS method has been applied for the determination of four naturally occurring aflatoxins AFB1, AFB2, AFG1, and AFG2 in nonalcoholic beer. Aflatoxins extraction from nonalcoholic beer was carried out using liquid–liquid extraction procedure. The effects of solvent‐types were studied to obtain maximum recovery of the target analytes with minimum contamination. Among different solvents, the aflatoxins extraction was best achieved using ethyl acetate. The obtained recoveries were ranged from 85 to 96% with good quality parameters: LOD values between 0.001 and 0.003 ng/mL, linearity of the calibration curve (r² > 0.999), and repeatability (run‐to‐run) and reproducibility (day‐to‐day) precisions with RSDs lower than 5% (n = 5) achieved at 0.50 ng/mL concentration. The optimized liquid–liquid extraction in combination with ultraperformance LC‐MS/MS was applied successfully to the analysis of AFB1, AFB2, AFG1, and AFG2 aflatoxins in 11 nonalcoholic beers and were detected up to 15.31 ng/L in some of the samples.     

Regulatory Role of Nano-Curcumin against Tartrazine-Induced Oxidative Stress,Apoptosis-Related Genes Expression,and Genotoxicity in Rats

The present study evaluates the regulatory effect of Nano-Curcumin (Nano-CUR) against tartrazine (TZ)-induced injuries on apoptosis-related gene expression (i.e., p⁵³, CASP-3 and CASP-9), antioxidant status, and DNA damages in bone marrow in treated rats. Male rats were arbitrarily separated into five groups, and each group was comprised of 10 rats each. The 1st group served as control (G1). The 2nd group ingested 7.5 mg TZ/kg. b.w. (body weight). The 3rd group ingested Nano-CUR 1 g/kg b.w. The 4th and 5th groups were respectively administered with (1 g Nano-CUR + 7.5 mg TZ/kg. b.w.) and (2 g Nano-CUR + 7.5 mg TZ/kg. b.w.). At the end of the experiment, blood samples, livers, and kidneys were collected. Livers and kidneys were homogenized and used for the analysis of reduced glutathione, malonaldhyde, total antioxidant capacity, lipid peroxide antioxidant enzyme activities, apoptosis-related gene expression, and genotoxicity by comit test. The ingestion of TZ for 50 days resulted in significant decreases in body, and kidney weights in rats and a relative increase in the liver weight compared to control. In contrast, the ingestion of Nano-CUR with TZ remarkably upgraded the body weight and relative liver weight compared to the normal range in the control. Aditionally, TZ ingestion in rats increased the oxidative stress biomarkers lipid peroxide (LPO) and malonaldehyde (MDA) significantly, whereas it decreased the reduced glutathione (GSH) levels and total antioxidant capacity (TAC). Similarly, the levels of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) significantly deteriorated in response to TZ ingestion. Moreover, the results revealed a remarkable up-regulation in the level of expression for the three examined genes, including p⁵³, CASP-3, and CASP-9 in TZ-ingested rats compared to the control. On the other hand, the comet assay result indicates that the ingestion of TZ induced DNA damage in bone marrow. Notably, the administration of Nano-CUR protected the kidney and liver of TZ-ingested rats as evidenced by a significant elevation in all antioxidant activities of tested enzymes (i.e, SOD, GPx, and CAT), vital recovery in GSH and TAC levels, and a statistical decrease in LPO and MDA compared to TZ-ingested rats. Interestingly, the ingestion of rats with TZ modulates the observed up-regulation in the level of expression for the chosen genes, indicating the interfering role in the signaling transduction process of TZ-mediated poisoning. The results indicate that the administration of Nano-CUR may protect against TZ-induced DNA damage in bone marrow. According to the results, Nano-CUR exerted a potential protective effect against oxidative stress, DNA damage, and the up-regulation of apoptosis-related genes induced by TZ ingested to rats.     

Chemical Approach Towards Broadband Spintronics on Nanoscale Pyrene Films

The injection of pure spin current into the non-magnetic layer plays a crucial role in transmitting, processing, and storing data information in the realm of spintronics. To understand broadband molecular spintronics, pyrene oligomer film (≈20 nm thickness) was prepared using an electrochemical method forming indium tin oxide (ITO) electrode/pyrene covalent interfaces. Permalloy (Ni₈₀Fe₂₀) films with different nanoscale thicknesses were used as top contact over ITO/pyrene layers to estimate the spin pumping efficiency across the interfaces using broadband ferromagnetic resonance spectra. The spintronic devices are composed of permalloy/pyrene/ITO orthogonal configuration, showing remarkable spin pumping from permalloy to pyrene film. The large spin pumping is evident from the linewidth broadening of 5.4 mT at 9 GHz, which is direct proof of spin angular momentum transfer across the interface. A striking observation is made with the high spin-mixing conductance of ≈1.02×10¹⁸ m⁻², a value comparable to the conventional heavy metals. Large spin angular moment transfer was observed at the permalloy-pyrene interfaces, especially at the lower thickness of permalloy, indicating a strong spinterface effect. Pure spin current injection from ferromagnetic into electrochemically grown pyrene films ensures efficient broadband spin transport, which opens a new area in molecular broadband spintronics.     

A novel light induced Knoevenagel condensation of Meldrum’s acid with aromatic aldehydes in aqueous ethanol

A highly efficient environment-friendly photochemical methodology has been developed for the condensation of Meldrum’s acid with aromatic aldehydes in water-ethanol solution sans any catalyst, support or promoter.     

Determination of capsaicinoids in Capsicum species using ultra performance liquid chromatography‐mass spectrometry

In the present work, a rapid and sensitive ultra performance liquid chromatography‐mass spectrometry method has been proposed for the analysis of capsaicinoids (nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin) present in different Capsicum samples. Extraction of capsaicinoids was carried out by liquid–liquid extraction using ethanol as an extracting solvent, while the chromatographic separation was achieved by reversed phase C₁₈ column with gradient mobile phase (solvent A: acetonitrile and solvent B: water with 0.1% formic acid). Under the optimum experimental conditions, the linear ranges were 0.5–50 μg/g with correlation coefficient (r²) >0.999 for each capsaicinoids and detection limits were 0.15, 0.05, 0.06, 0.2, and 0.1 μg/g for nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin, respectively. Run‐to‐run and day‐to‐day precisions of the method with relative standard deviations <1.5% were achieved for all analyzed capsaicinoids. The robustness of the method was determined by utilizing different injection volumes of the extracts. Furthermore, to validate the system robustness, a run of high number of capsaicinoids present in different varieties of Capsicum samples was performed in this study. All the capsaicinoids were separated in a time of less than 9 min by employing the proposed method.     

Ruthenium monoterpyridine complexes with 2,6-bis(benzimidazol-2-yl)pyridine: Synthesis,spectral properties and structure

Ruthenium monoterpyridine complexes with the tridentate 2,6-bis(benzimidazol-2-yl)pyridine (LH₂), [Ru(trpy)(LH₂)]²⁺, [1]²⁺ and [Ru(trpy)(L²⁻)], 2 (trpy = 2,2′:6′,2″-terpyridine) have been synthesized. The complexes have been authenticated by elemental analyses, UV–Vis, FT-IR, ¹H NMR spectra and their single crystal X-ray structures. Complexes [1]²⁺ and 2 exhibit strong MLCT band near 475 and 509 nm, respectively, and are found to be very much dependent on solution pH. The successive pH dependent dissociations of the N–H protons of benzimidazole moiety of LH₂ in [1]²⁺ lead to the formation of 2. The proton induced inter-convertibility of [1]²⁺ and 2 has been monitored via UV–Vis spectroscopy and redox features. The two pK_a values, 5.75 and 7.70, for complex [1]²⁺ have been determined spectroscopically.