Monohydrogen phosphate selective electrode based on a synthetic hydrotalcite

Solid Contact Potentiometric Sensors Based on a New Class of Ionic Liquids on Thiacalixarene Platform

New solid-contact potentiometric sensors have been developed for hydrogen phosphate recognition on the basis of ionic liquids containing tetrasubstituted derivatives of thiacalix[4]arene in cone and 1,3-alternate conformations with trimethyl- and triethylammonium fragments at the lower rim substituents. The recognition of selected anions including carbonate, hydrogen phosphate, perchlorate, oxalate, picrate, and EDTA was conducted using electrochemical impedance spectroscopy with ferricyanide redox probe. For the potentiometric sensor assembling, the ionic liquids were stabilized by multiwalled carbon nanotubes and carbon black deposited on the glassy carbon electrode. The influence of support, steric factors and modification conditions on the sensor performance has been investigated. As was shown, potentiometric sensors developed make it possible to selectively determine hydrogen phosphate anion within the concentration range from 1 × 10⁻² to 1 × 10⁻⁶ M and limit of detection of 2 × 10⁻⁷−1 × 10⁻⁶ M with unbiased selectivity coefficients varied from 1.2 × 10⁻¹ to 1.0 × 10⁻⁸ (carbonate, acetate, oxalate, succinate, glutharate, glycolate, and malonate anions).

Indigo Carmine-Cu complex probe exhibiting dual colorimetric/fluorimetric sensing for selective determination of mono hydrogen phosphate ion and its logic behavior

A new selective probe based on copper complex of Indigo Carmine (IC-Cu₂) for colorimetric, naked-eye, and fluorimetric recognition of mono hydrogen phosphate (MHP) ion in H₂O/DMSO (4:1v/v, 1.0mmolL^-1 HEPES buffer solution pH7.5) was developed. Detection limit of HPO₄^2- determination, achieved by fluorimetric and ₃lorimetric method, are 0.071 and 1.46μmolL^-1, respectively. Potential, therefore is clearly available in IC-Cu₂ complex to detect HPO₄^2- in micromolar range via dual visible color change and fluorescence response. Present method shows high selectivity toward HPO₄^2- over other phosphate species and other anions and was successfully utilized for analysis of P₂O₅ content of a fertilizer sample. The results obtained by proposed chemosensor presented good agreement with those obtained the colorimetric reference method. INHIBIT and IMPLICATION logic gates operating at molecular level have been achieved using Cu²⁺and HPO₄^2- as chemical inputs and UV-Vis absorbance signal as output.