We report spectrophotometric methods for quantifying sodium and potassium in serum and plasma without sample pretreatment or solvent-extraction steps. The methods are based on novel chromogenic ionophores characterized by molecular structures highly preorganized for binding, which result in exceptionally high sensitivity and selectivity (negligible responses to sodium at 80 to 200 mmol/L in the...

Sol-gel and polymeric membrane electrodes, based on thiacalix[4]arene as a neutral carrier, weresuccessfully developed for the detection of VO2+ in aqueous solutions. The sol-gel and PVCmembrane electrodes exhibited linear response with Nernstian slopes of 29.3 and 28.4 mV perdecade, respectively, within the vanadyl ion concentration ranges from 1.0 × 10-6 to 1.0 × 10-1mol dm-3 and from 1.0 × 1...

Electrodes for scanning ion-selective potentiometric microscopy (or potentiometric SECM) were developed and used to image local concentration profiles of NH4+, K+, and Zn2' ions. Neutral carrier-based micropipet ionselective electrodes with high spatial resolution (-2-3 pm) and fast response time (-300 ms) were fabricated and employed as potentiometric SECM tips, and highresolution ion-selectiv...

Enzyme sensor for organophosphorus insecticides organophosphorus hydrolase in a polymer membrane on a pH sensor is used to catalyse the hydrolysis of compounds with phoshate ester functionality. The detected [H+] change is proportional to the concentration of the phosphate ester insecticide. This is a good example of the use of an enzyme to give selectivity to a specific class of compounds. Unf...

In this work, the results concerning to the mean activity coefficient measurements for NaCl in the (glycerol + water) system using the potentiometric method are reported. The potentiometric measurements were performed on the galvanic cells without liquid junction of the type: Ag|AgCl|NaCl (m), glycerol (wt%), H2O (1 - wt)%|Na-ISE, in various mixed solvent systems containing 0, 5, 10,...

Novel biscrowns 1 and 2 were synthesized from 13-membered azobenzocrown ethers containing bromoalkylenoxy chains in para position relative to the azo group. The synthesized diester molecules are dodecylmethylmalonic acid derivatives differing by the linker length. The synthesized compounds have the potential of being used as sodium ionophores in ion-selective electrodes. They were characterized...

AIM The aim of the present study was to evaluate the relationship of drinking water fluoride levels with children's intelligence quotient (IQ). MATERIALS AND METHODS Water was collected from initially identified endemic fluoride regions according to the geological research of Government of India. Fluoride concentration of the water was assessed by utilizing fluoride ion selective electrode, O...

OBJECTIVE To test the hypothesis that glucose ingestion leads to a decrease in plasma ionized calcium (iCa) and ionized magnesium (iMg) during the third trimester of pregnancy. METHODS We studied 54 women who underwent a 50 g glucose challenge test (GCT) and 27 women who underwent a 3-hour 100 g glucose tolerance test (GTT) because of an abnormal GCT. Plasma glucose was measured with an autom...

We studied the stability and linearity of the AVL and Nova Mg and Ca ion-selective electrodes and the relation between the ionized Ca and ionized Mg results reported by each analyzer. The response of the electrodes to different concentrations of Mg and Ca was determined for saline solutions, aqueous solutions, and serum samples. The electrodes from both manufacturers demonstrated acceptable sta...