Nitrite-selective ISE based on uranyl salophen derivatives

Anion selectivities of membranes based on uranyl salophen derivatives with substituents at the 4-position are presented. Derivative 2 (with 4-nitro substituent) has been applied to design a nitrite-selective ion-selective electrode (ISE) that shows linear response in the range 1¿3 of pNO2¿ with a slope of 56.2 mV decade¿1. The highest selectivity over other anions and optimum performance of the electrodes are obtained for membranes containing tridodecylmethylammonium chloride (TDMAC) at 10 mol% versus ionophore as an additive

Durable phosphate-selective electrodes based on uranyl salophenes

Lipophilic uranyl salophenes derivatives were used as ionophores in durable phosphate-selective electrodes. The influence of the ionophore structure and membrane composition (polarity of plasticizer, the amount of incorporated ionic sites) on the electrode selectivity and long-term stability were studied. The highest selectivity for H2PO4− over other anions tested was obtained for lipophilic uranyl salophene III (with t-butyl substituents) in poly(vinylchloride)/o-nitrophenyl octyl ether (PVC/o-NPOE) membrane containing 20 mol% of tetradecylammonium bromide (TDAB). Moreover, phosphate-selective electrodes based on this derivative exhibited the best long-term stability (2 months). The electrode durability can be improved decreasing the amount of the ammonium salt in membrane to 5 mol%.\ud \u

Durability of phosphate-selective CHEMFETs

Lipophilic uranyl salophenes derivatives I and II were used as ionophores in membranes of phosphate-selective CHEMFETs. High selectivity for H2PO4− over other anions was obtained for these sensors. The influence of the ionophore structure on the sensor durability was investigated. CHEMFETs based on derivative II exhibited better long-term stability due to the better solvation of this ionophore in the membrane phase. The microsensor durability can be improved decreasing the amount of the ammonium salt in the membrane to 5% mol, with only little decrease of initial selectivity.\ud \u

Uranyl salophenes as ionophores for phosphate-selective electrodes

Anion selectivities of poly(vinylchloride) (PVC) plasticized membranes containing uranyl salophene derivatives were presented. The influence of the membrane components (i.e. ionophore structure, dielectric constant and structure of plasticizer, the amount of incorporated ammonium salt) on its phosphate selectivity was investigated. The highest selectivity for H2PO4− over other anions tested was obtained for lipophilic uranyl salophene III (without ortho-substituents) in PVC/o-nitrophenyl octylether (o-NPOE) membrane containing 20 mol% of tetradecylammonium bromide (TDAB). Ion-selective electrodes (ISEs) based on these membranes exhibited linear response in the range 1–4 of pH2PO4− with a slope of 59 mV/decade. The introduction of ortho-methoxy substituents in ionophore structure decreased the phosphate selectivity of potentiometric sensors