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This study assessed the concentrations of several trace and heavy metals in bottled drinking water. A total of 27 samples were collected from Yemeni markets. The ICP-MS (inductively coupled plasma-mass spectrometry) technique was utilized to analyze the levels of Li, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Se, Rb, Ag, Cd, Cs, Ba, Hg, Tl, Pb, and U. Furthermore, the study also examined the levels of total dissolved solids (TDS), electrical conductivity (EC), and pH in the collected samples. The concentrations of the elements in the bottled drinking water samples were compared to the maximum allowable concentration (MAC) values for these elements in drinking water, set by the World Health Organization (WHO) and Yemen’s Ministry of Water and Environment (YMWE). The limit of detection (LOD) and recovery ranged from 0.0003 to 1.86 μg/l, 80 to 120 %, respectively. Only trace elements Mn and Pb were detected in all samples at concentrations below the LOD. Out of the elements examined, only Hg exceeded the acceptable limits defined by both the WHO and YMWE in most of the samples.

A closed-vessel microwave digestion method was developed for the simultaneous determination of macro, micro, and toxic elements (Mg, K, Ca, Al, Mn, Fe, Cu, Zn, Se, Rb, V, Cd, and As) in wheat by inductively coupled plasma mass spectrometry (ICP-MS). A two-level factorial design with four variables was employed to determine the optimal conditions for the significant parameters. The optimal conditions for microwave digestion of ground wheat samples were found to be 0.5 g of the sample, 9 mL of 8 mol/L HNO3, and 3 mL of 33% H2O2 at 210°C. The analytical method was validated, and the accuracy of the method was then evaluated through analysis of wheat flour-certified standard reference materials (NIST SRM 1567b). The validated procedure was subsequently applied to the analysis of 12 wheat samples sourced from local farms in the Al-Qassim region and a further six samples purchased from the Al-Qassim markets, covering six imported brands common in Saudi Arabia. The results of the study showed that the level of minerals in wheat grown in desert areas is higher than in other areas. The concentrations of macroelements and microelements in the Al-Qassim samples exceeded those of the imported samples by 12.41% and those of the samples from other countries by 33.90%. The results were also evaluated using multivariate analysis techniques: principal component analysis (PCA) and hierarchical cluster analysis (HCA).

A new coumarin derivative, (E)-3-(3-(4-(dimethylamino) phenyl) acrylo-yl)-4-hydroxy-2H-chromen-2-one (3), was synthesized by the condensation of 3-acetyl-4-hydroxycoumarin (1) with 4-N,N-dimethylaminobenzaldehyde (2) in the presence of piperidine in ethanol. The structure of the synthesized compound was characterized using spectroscopic data (IR and 1H NMR) and elemental analysis. The antimicrobial properties and acetylcholinesterase inhibition activity (AChEI) of coumarin 3 were investigated, with the highest observed AChEI activity providing 48.25% inhibition. The electronic absorption and emission spectra revealed that 3 exists as two, main keto-enol tautomers. The ratios of these tautomers in both protic and aprotic solvents with different polarities and dielectric constants were calculated. The fluorescence of coumarin 3 was enhanced upon increasing the medium viscosity, which was due to the resultant molecular rigidity. This criterion was further investigated using DNA, whereby 3 showed enhanced fluorescence upon its uptake in DNA grooves and was therefore tested as a novel DNA fluorescent stain.