3-Aminopyridine Salicylidene: A Sensitive and Selective Chemosensor for the Detection of Cu(II), Al(III), and Fe(III) with Application to Real Samples.

Interest in developing selective and sensitive metal sensors for environmental, biological, and industrial applications is mounting. The goal of this work was to develop a sensitive and selective sensor for certain metal ions in solution. The goal was achieved via (i) preparing the sensor ((E)-2-((pyridine-3-ylimino)methyl)phenol) (3APS) using microwave radiation in a short time and high yield and (ii) performing spectrophotometric titrations for 3APS with several metal ions. 3APS, a Schiff base, was prepared in 5 min and in a high yield (95%) using microwave-assisted synthesis. The compound was characterized by FTIR, XRD, NMR, and elemental analysis. Spectrophotometric titration of 3APS was performed with Al(III), Ba(II), Cd(II), Co(II), Cu(II), Fe(III), Mn(II), Ni(II), and Zn(II). 3APS showed good abilities to detect Al(III) and Fe(III) ions fluorescently and Cu(II) ion colorimetrically. The L/M stoichiometric ratio was 2:1 for Cu(II) and 1:1 for Al(III) and Fe(III). Low detection limits (µg/L) of 324, 20, and 45 were achieved for Cu(II), Al(III), and Fe(III), respectively. The detection of aluminum was also demonstrated in antiperspirant deodorants, test strips, and applications in secret writing. 3APS showed high fluorescent selectivity for Al(III) and Fe(III) and colorimetric selectivity towards Cu(II) with detection limits lower than corresponding safe drinking water guidelines.

Concentrations of essential and toxic elements and health risk assessment in brown rice from Qatari market.

Twenty-two brown rice varieties available in the Qatari market were analyzed for essential and toxic elements by ICP-MS. Found concentrations (µg/kg) were: As: 171 ± 78 (62-343), Cd: 42 ± 60 (4-253), Cr: 515 ± 69 (401-639), Pb: 6 ± 7 ( 1 in million, may possibly be > 1 in 10,000 based on conservatively high brown rice consumption rates of 200 g/d or 400 g/d in Qatar. These elevated risks may be applicable to specific population subgroups with diabetic conditions who consume only brown rice. Non-cancer risks are mainly derived from Mn, V, Se, and Cd with a hazard index > 1 from some brown rice samples.

Diversity of arbuscular mycorrhizal fungi and its chemical drivers across dryland habitats.

Qatar is largely characterized by a hyper-arid climate and low soil fertility which create a stressful soil environment for arbuscular mycorrhizal (AM) fungi. In a study of AM fungal communities and their relationship with soil chemical characteristics, we used a high-throughput sequencing technique to explore AM fungal diversity and community composition in different habitats across Qatar. We identified a total of 79 AM fungal taxa, over 77% of which were species from the Glomeraceae family. The lowest AM fungal diversity was observed in saltmarsh and in one rawdha site, while the highest richness, effective number of species, and diversity were observed in rawdha and sabkha communities. NMDS and multiple regression analyses showed that AM fungi were negatively correlated with soil pH and TC, but positively correlated with K and NO3-. AM fungi also were positively correlated with Cd, with the latter suggesting that very low levels of heavy metals may not always be harmful to AM fungi. These findings provide baseline information on AM fungal assemblages and the chemical drivers of diversity across communities in Qatar. This work partly compensates for the current lack of broad-scale studies in the Arabian Peninsula by providing understanding of overall patterns of AM fungi and their drivers in the region.

Zebrafish larvae as a model to demonstrate secondary iron overload.

OBJECTIVES: Thalassemia is the most common genetically inherited blood disorder arising from a defect in hemoglobin production, resulting in ineffective erythropoiesis and severe hemolytic anemia. While transfusion therapy corrects the anemia, it gives rise to secondary iron overload. Current iron chelation therapy performed using deferoxamine, and the efficiency of this drug was demonstrated here using the zebrafish animal model. METHODS: Zebrafish larvae were exposed for 3 days to iron [100 µmol L-1 ferric ammonium citrate; 3-6 days post fertilization (dpf)]. Then, iron treated larvae were exposed to 100 µmol L-1 deferoxamine for 3 days (6-9 dpf). Total tissue iron concentration in the whole larvae, assessed by three different assays; inductively coupled plasma mass spectrometry, colorimetry (spectrophotometry), and microscopy using iron staining followed by imaging and quantification. RESULTS: The three assays showed that iron treatment alone resulted in a significant increase in total iron. Deferoxamine treatment of the iron-loaded zebrafish larvae showed a significant decrease in total iron concentration. CONCLUSION: This study presented a clear evidence of the effectiveness of zebrafish larvae to use as a tool to study iron overload and open the door for studying the efficiency of potential new iron chelating compounds other than commercially available ones.