Development of LC-MS/MS analytical method for the rapid determination of Diquat in water and beverages.

This study aimed to develop simple, fast, and sensitive methods for the determination of diquat (DQ) in various matrices such as water and beverages. For water, direct injection was tested first, however, the sensitivity of the incurred samples were too low and couldn't possibly achieve the targeted limit of quantification. Hence, dilution with "weaker" injection solvents were tested, and the final conditions involved the dilution of water with acetonitrile (0.4 % ammonium hydroxide) which increased the sensitivity by more than ten times. Nevertheless, the beverages samples needed further treatment to achieve acceptable spiked recovery. The final conditions involved extraction using the aforementioned solvent, followed by heating and partitioning. Both of the methods satisfied the validation requirements, with an average recovery ranging from 85.9 to115 % and associated relative standard deviation (RSD %) within the range 3-8. Further applications on real samples were done to test the levels of contamination.

Synergistic Effects of Kaolin and Silicon Nanoparticles for Ameliorating Deficit Irrigation Stress in Maize Plants by Upregulating Antioxidant Defense Systems.

Water deficit is a significant environmental stress that has a negative impact on plant growth and yield. In this research, the positive significance of kaolin and SiO2 nanoparticles in moderating the detrimental effects of water deficit on maize plant growth and yield is investigated. The foliar application of kaolin (3 and 6%) and SiO2 NPs (1.5 and 3 mM) solutions increased the growth and yield variables of maize plants grown under normal conditions (100% available water) and drought stress conditions (80 and 60% available water (AW)). In addition, plants treated with SiO2 NPs (3 mM) demonstrated increased levels of important osmolytes, such as proline and phenol, and maintained more of their photosynthetic pigments (net photosynthetic rate (PN), stomatal conductance (gs), intercellular CO2 concentration (Ci), and transpiration rate (E)) than with other applied treatments under either stress or non-stress conditions. Furthermore, the exogenous foliar application of kaolin and SiO2 NPs also reduced the amounts of hydroxyl radicals (OH), superoxide anions (O2), hydrogen peroxide (H2O2), and lipid peroxidation in maize plants experiencing a water deficit. In contrast, the treatments led to an increase in the activity of antioxidant enzymes such as peroxidase (POX), ascorbate peroxidase (APX), glutathione peroxidase (GR), catalase (CAT), and superoxide dismutase (SOD). Overall, our findings indicate the beneficial impact of the application of kaolin and silicon NPs, particularly the impact of SiO2 NPs (3 mM) on managing the negative, harmful impacts of soil water deficit stress in maize plants.

Bioremediation of aflatoxins by some reference fungal strains.

Aspergillus parasiticus RCMB 002001 (2) producing four types of aflatoxins B1, B2, G1, and G2 was used in this study as an aflatoxin-producer. Penicillium griseofulvum, P. urticae, Paecilomyces lilacinus, Trichoderma viride, Candida utilis, Saccharomyces cerevisiae as well as a non-toxigenic strain of Aspergillus flavus were found to be able to exhibit growth on aflatoxin B1-containing medium up to a concentration of 500 ppb. It was also found that several fungal strains exhibited the growth in co-culture with A. parasiticus, natural aflatoxins producer, and were able to decreased the total aflatoxin concentration, resulting in the highest inhibition percentage of 67.2% by T viride, followed by P. lilacinus, P. griseofulvum, S. cerevisiae, C. utilis, P. urticae, Rhizopus nigricans and Mucor rouxii with total aflatoxin inhibition percentage of 53.9, 52.4, 52, 51.7, 44, 38.2 and 35.4%, respectively. The separation of bioremediation products using GC/MS revealed that the toxins were degraded into furan moieties.