Release characteristics of potassium from native reserves of some calcareous soils of Iran and their relationship with yield and potassium uptake by ryegrass (Lolium perenne L.)

Information on the release of potassium (K) reserves in soils can improve K-fertiliser management. The purpose of this study was to investigate the available K-release capacity of soils and its relationship with plant responses in three soil orders. Six consecutive ryegrass cultivations were conducted on nine soil samples from surface (0–30 cm) horizons of Vertisols, Alfisols, and Inceptisols of three sites with different temperature and precipitation under greenhouse conditions. The K release was investigated using 0.2 M sodium tetraphenylboron extractant during 0.2–144 h. The cumulative release of K ranged within 243–895 mg kg–1 at 0.2 h and 620–1788 mg kg–1 at 144 h. Kinetics of K release from soils at two time intervals (0.2–2 and 2–144 h) were described well by power function and pseudo second-order equations. The growth of ryegrass was somewhat stunted after six consecutive cultivations. Significant correlations were observed between dry matter and K uptake of ryegrass. The parameters of the best fitted kinetic models were significantly correlated with plant responses, especially the uptake of K by ryegrass.

A high temperature reversible phase transition in a supramolecular complex of 15-crown-5 with tetraphenylboron sodium

High temperature (391 K) reversible phase transition and large thermal hysteresis (19 K) was observed in 15-crown-5 clathrates: [Na(15-crown-5)][BPh4] (15-crown-5 = 1,4,7,10,13-pentaoxacyclopentadecane, NaBPh4 = sodium tetraphenylboron).

Quantitative Rapid Analysis Method for Ofloxacin in Raw Milk Based on Molecule-Specific Recognition and Electrochemical Impedance Spectrum

A quantitative rapid analysis method for ofloxacin detection in raw milk using molecule-specific recognition and an electrochemical impedance spectrum (EIS) technique was investigated in this study. An association complex (AC) formed by a combination of ofloxacin and sodium tetraphenylboron (ST) was used as the active material for electrochemical analysis. A carbon screen-printed electrode (CSE) was modified with the AC to form an electrochemical active membrane for ofloxacin detection. EIS data of pretreated raw milk samples were measured and analyzed with a non-linear bistable stochastic resonance (SR) model. Trace ofloxacin concentrations were characterized by SR output signal-to-noise ratio (SNR) eigen values. An ofloxacin quantitative analysis model was built based on SNR eigen values. Experimental results demonstrated that the proposed method presented good accuracy, repeatability, and recovery. It is a promising way for ofloxacin detection in raw milk. Keywords: Association complex, Electrochemical impedance spectrum, Ofloxacin, Quantitative analysis, Sodium tetraphenylboron.

A ditopic calix[4]pyrrole amide derivative: highlighting the importance of fundamental studies and the use of NaPh4B as additive in the design and applications of mercury(ii) ion selective electrodes

A ditopic calix[4]pyrrole amide based ion selective electrode and its applications are first reported. Sodium tetraphenylboron currently used as additive in Hg ISE is by itself a sensor for mercury(ii).