No abstract

Arsenic (As) contamination in the soil adversely affects crop productivity, grain quality, and human health. A pot experiment was performed to assess the sole and combined effects of Si and biochar on growth, physiological and antioxidant defense mechanisms, yield, and grain quality of maize. Soil treatments comprised of control (no treatment), As, Si, biochar, Si + biochar, As + Si, As + biochar, and As + Si + biochar placed in a completely randomized design with three replications. As toxicity significantly reduced chlorophyll a (5.18%), chlorophyll b (33.87%), chlorophyll a + b (11.67%), and primary metabolites [soluble protein (54.93%), amino acids (24.85%), total soluble sugars (39.77%), and phenolic contents (25.88%)], while increasing the activities of enzymatic antioxidants such as superoxide dismutase (SOD) by 43.51%, peroxidase (POD) by 47.93%, catalase (CAT) by 47.98%, and ascorbate peroxidase (APX) by 59.02%, as well as that of lipid peroxidation in the leaves of maize. In addition, As contamination reduced the grain yield and yield-related attributes relative to the respective controls. Among the soil applications, the interactive effect of Si and biochar improved maize grain yield (12.12%) by triggering activities of enzymatic antioxidants and proline contents and reducing the H2O2 and MDA contents. The combined application of Si and biochar enhanced the Si contents in shoots of the control and As-contaminated plants, while significantly reducing As concentration in shoots (69%) and grains (142%). In conclusion, the combined application of Si and biochar was found to be a fruitful soil amendment strategy to improve the yield of maize and reduce the toxic limit of As under As-contaminated soil. The results of this study may be useful for the cultivation of food crops under AS-contaminated soils, but before commercial recommendation, more trails are required under field conditions.

The greening of analytical methods has gained interest in the quantitative analysis field to reduce environmental impact and improve safety health conditions for analysts. Nirmatrelvir plus ritonavir is a new FDA approved co-packaged medication developed for the treatment of COVID-19. The aim of this research was to develop green fitted HPLC method using pre experimental computational testing of different stationary phases as well as selecting mobile phase regarding to green analytical chemistry principles. Computational study was designed to test the physical interaction between nirmatrelvir and ritonavir and different columns (C8, C18, Cyano column). The study showed that the C18 column was better for simultaneous HPLC analysis of the cited drugs. Regarding to green point of view, mobile phase consisted of ethanol: water (80:20, v/v) provided an efficient chromatographic separation of nirmatrelvir and ritonavir within a short analytical run time, reasonable resolution and excellent sensitivity. Isocratic elution was performed on a selected C18 column and a green adjusted mobile phase at flow rate of 1 mL/min and UV detection at 215 nm. The chromatographic system allowed complete baseline separation with retention times of 4.9 min for nirmatrelvir and 6.8 min for ritonavir. The method succeeded to determine nirmatrelvir and ritonavir over the concentration range of 1.0–20.0 μg/mL in the pure form and in pharmaceutical dosage form. Greenness profiles of the applied HPLC method was assessed using analytical eco-scale, the green analytical procedure index and the AGREE evaluation method. The results revealed adherence of the described method to the green analytical chemistry principles. The authors hope to provide a promising challenge for achieving green goals through integrating computational tools and applying them with green assessment metrics.