Calcium disodium ethylenediaminetetraacetate as a safe compound for crop protection with the potential to extend the basic substances group

Excessive use of commercial synthetic fungicides in agriculture is a globally discussed issue. This topic is seen as particularly important in modern plant protection and cultivation systems, where the total fungicide burden of the agroecosystem should be controlled and reduced. Basic substances (BSs) are a relatively novel, legally recognised group of substances which can be applied. The present study tested calcium disodium ethylenediaminetetraacetate (CaNa₂-EDTA), a substance whose properties and environmental safety make it another useful alternative for plant protection in modern farming. The study demonstrated the high antifungal activity of the substance against Pyrenophora (anamorph: Drechslera) tritici-repentis (Died.) Drechsler, (MIC50 0.195–0.223 mg/ml), safety for plant tissue and especially for non-target organisms, and positive effects on the yield of wheat (Triticum aestivum Linnaeus). CaNa₂-EDTA surpassed the effect of chitosan hydrochloride, a registered and utilised substance, and a synthetic conventional fungicide. CaNa₂-EDTA is an excellent candidate for registering within the BS group, with benefits for environmentally sound systems in plant protection.

A Modifiedo-Phthalaldehyde Fluorometric Analytical Method for Ultratrace Ammonium in Natural Waters Using EDTA-NaOH as Buffer

In the existence of appropriate amount of disodium ethylenediaminetetraacetate (EDTA), precipitation would not occur in seawater and other natural waters even if the sample solution was adjusted to strong basicity, and the NH3-OPA-sulfite reaction at the optimal pH range could be used to determine ammonium in natural waters. Based on this, a modifiedo-phthalaldehyde fluorometric analytical method has been established to determine ultratrace ammonium in natural waters. Experimental parameters, including reagent concentration, pH, reaction time, and effect of EDTA, were optimized throughout the experiments based on univariate experimental design. The results showed that the optimal pH range was between 10.80 and 11.70. EDTA did not obviously affect the fluorometric intensity. The linearity range of the proposed method was 0.032–0.500 µmol/L, 0.250–3.00 µmol/L, and 1.00–20.0 µmol/L at the excitation/emission slit of 3 nm/5 nm, 3 nm/3 nm, and 1.5 nm/1.5 nm, respectively. The method detection limit was 0.0099 µmol/L. Compared to the classical OPA method, the proposed method had the advantage of being more sensitive and could quantify ultratrace ammonium without enrichment.

Preparation and Release Behavior of Polyelectrolyte Microcapsules

Hybrid calcium carbonate (CaCO3)/poly(styrene sulfonate) (PSS) particle, as a template, was synthesized using colloidal crystallization with the presence of nitrate tetrahydrate (Ca(NO3)2•4H2O), sodium carbonate (Na2CO3) and PSS. Microcapsule was prepared by template-assisted layer-by-layer (LbL) technology in solutions of two oppositely charged polyelectrolytes, poly(styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) alternately, followed by dissolving the template with disodium ethylenediaminetetraacetate (EDTA). The release behavior of rhodamine B (RhB) from the microcapsules was examined and the rates of release at different pH were studied.