Selectivity enhancement of membrane introduction mass spectrometry of nonpolar alkanes, alkenes, and aromatic hydrocarbons in air samples by application of nitric oxide chemical ionization (NOCI/MIMS) is demonstrated. Membrane methods are useful for separating compounds (usually nonpolar organics) from air and water samples without costly and time-consuming sample preparation, and coupled with mass spectrometry, they provide good sensitivity. But they often suffer from lack of specificity in mixture analysis, particularly for saturated organics. Nitric oxide chemical ionization is able to produce strong unique ion signals for many hydrocarbon test compounds that can be used to identify and quantify the parent neutrals. Our observed detection limits for a number of test compounds were relatively high; however, the method could potentially be useful for environmental analytical applications (e.g., plume tracking) if the monitored compound was at elevated levels or if NOCI/MIMS is coupled with a trapping method.

A new method that we describe as chemical modulation of volatile hydrocarbons is investigated using ozonolysis pretreatment and membrane introduction mass spectrometry (MIMS). This extension to the MIMS technique is intended to enhance the selectivity of MIMS for measuring hydrocarbons in the complex mixtures often encountered in polluted air samples. The test samples for this study were dilute (parts per billion by volume, ppbv) two-component hydrocarbon mixtures in synthetic air. Ozone reacted to completely suppress the MIMS signal from beta-pinene in a mixture of toluene and beta-pinene and the MIMS signal from cyclohexene in a mixture of cyclohexene and cyclohexane. As expected, the ozone reaction produced little attenuation of the MIMS signal from toluene and cyclohexane in the test mixtures. The basis of the method is that the products of the ozonolysis, which is rapid for alkenes, are polar compounds that are excluded by the membrane used here, as confirmed in this study. Since the modulation only affects unsaturated hydrocarbons (and other similar organic compounds), the method can be used to aid in quantitative analysis of volatile hydrocarbon compounds in air samples for air pollution monitoring.

The current research has centered on the use of pharmacological and binding affinity methods to test the 36 compounds as bioactive constituents’ inhibitors for COVID-19. Six compounds out of 36 phytoconstituents (rutin, quercetin, catechin gallate, rhamnetin, campesterol and stigmasterol) have demonstrated outstanding molecular docking and drug-like properties as HIV inhibitors Lopinavir and Indinavir. Interestingly, the lowest binding energies (LBE) and the inhibition constant ( K i ) have showed that these compounds are able to bind to the P-glycoprotein substrate of 3CL pro and Nsp15. Interestingly, rutin has been found to be an excellent potential inhibitor for COVID-19 proteins because it has the best LBE score and K i value than those of other compounds, and of its ability to form strong H-bonds with COVID-19 proteins. The compounds that come next to the rutin compound are stigmasterol and campesterol. As a result, these compounds are considered possible novel inhibitors of COVID-19. In order to validate the computational results, more in vitro and in vivo investigations are required to support the findings of this research.

The bivariate calibration method was used for quantification of hydrochlorothiazide/enalapril maleate and hydrochlorothiazide/bisoprolol fumarate in pharmaceutical tablets. The determination of hydrochlorothiazide/enalapril maleate is made using new absorption wavelengths at 211 and 272 nm, while hydrochlorothiazide/bisoprolol fumarate is made at new wavelengths 273.5 and 293 nm. The results are compared favorably to those obtained from HPLC. The method is simple, time saving, and costly effective; it could be used to determine the pharmaceutical compounds in commercial available products.

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Green and sensitive spectrofluorometric methods have been developed and validated for the determination of timolol maleate (TML)/hydrochlorothiazide (HCT) and amiloride hydrochloride (AMH)/hydrochlorothiazide in tablets. The proposed spectrofluorometric procedures were found to be linear in the range of 4–12, 5–35 and 0.025–0.2 mg L−1 for HCT, TML and AMH, resp. The excitation and emission wavelengths for HCT, TML and AMH at room temperature were 270 and 375, 295 and 435, 330 and 415 nm, resp. The methods were validated with respect to ICH guidelines. The AMH showed higher sensitivity with lower values of LOD and LOQ values compared to HCT and TML. The proposed methods were applied to two pharmaceutical formulations; the method for HCT and AMH has proven as reliable assaying method, whereas the method for TML, when combined with HCT, is applicable to screening semi-quantitative analyses.

A series of lanthanides(III) complexes containing Schiff base ligand, {[LnL(NO 3 ).H 2 O]•xH 2 O {Ln: La, Pr, Nd, Sm, Eu, Gd, Tb, and Dy, H 2 L: N,N-bis-(2-hydroxy-5-nitro-benzylidene)-1,2-phenylenediamine Schiff base ligand}, have been synthesized by reaction of the ligand with Ln(NO 3 ) 3 •xH 2 O in the presence of NaOH.Structures of these complexes have been characterized by elemental analysis, molar conductivity, thermal gravimetric and various spectral methods (IR, UV-Vis, 1 H, and 13 C NMR). The proposed formula, of the complexes consists of one Ln(III) ion with the coordination number of seven. Two coordination sites are occupied by one bi-dentate nitrate anion, another site is occupied by one water molecule and the remaining four coordination sites are occupied by one deprotonated tetra-dentate ligand molecule. Fluorescence emission spectra of Ln(III) complexes exhibit ligand-centred emission peak with a blue shift compared with that of free H 2 L. This can be explained on the basis of ligand-to-metal charge transfer (LMCT) that occurs upon L -2 coordination to Ln(III) ions. Antibacterial activity of H 2 L and its Ln(III) complexes has been tested against some gram-positive and gram-negative bacterial strains.

CDK1 (cyclin dependent kinase 1) is a key regulator of the cell cycle and is frequently dysregulated in cancer, making it a promising target for anticancer therapy. Securigera securidaca L. (S. securidaca) seeds, traditionally used in folk medicine for various ailments including cancer, were examined for their potential as CDK1/Cks2 inhibitors using in silico approaches. A total of 14 phytocompounds was identified in the GC/MS chromatogram, with gingerone being the most abundant at 25.67% and hippeastrine the least at 2%. Major constituents of the essential extract, including gingerol, eugenol, α-curcumene, and gingerol, showed high values and made up 52% of the total content of the volatile extract. Molecular docking and ADMET studies suggested that hippeastrine and naringenin are potential hit candidates against CDK1, exhibiting good drug-like properties and molecular interactions with desirable pharmacokinetic and toxicological characteristics close to dinaciclib. Furthermore, molecular dynamics (MD) simulations showed that both compounds exhibited stable conformations inside the binding site over the 100 ns MD simulation, suggesting they may stabilize the protein structure by reducing the flexibility of the CDK1 backbone. Additionally, MM-PBSA calculations further supported the stability of hippeastrine and naringenin in CDK1 complexes. Overall, these findings suggest that hippeastrine and naringenin are potential hit candidates for CDK1 inhibition, providing valuable insight into their binding and stability within the active site of CDK1. Further investigation of these compounds with in vitro and in vivo assays is warranted to assess their potential as CDK1 inhibitors for cancer therapy.