Abstract (EN):
In this work, the new polyamine bisnaphthalimidopropyl-4,4'-diaminodiphenylmethane is proposed as a new ionophore for perchlorate potentiometric sensors. The optimal formulation for the membrane comprised of 12 mmol kg(-1) of the ionophore, and 68% (w/w) of 2-nitrophenyl phenyl ether as plasticizer and 31% (w/w) of high molecular weight PVC. The sensors were soaked in water for a week to allow leakage of anionic impurities and for one day in a perchlorate solution (10(-4) mol L-1) to improve reproducibility due to its first usage. The stability constant for the ionophore-perchlorate association in the membrane, log beta(IL1)=3.18 +/- 0.04, ensured a performance characterized by the slope of 54.1 (+/- 0.7) mV dec(-1) to perchlorate solutions with concentrations between 1.24 x 10(-7) and 1.00 x 10(-3) mol L-1. The sensors are insensitive to pH between 3.5 to 11.0, they have a practical detection limit of 7.66 (+/- 0.42) x 10(-8) mol L-1 and a response time below 60 s for solutions with perchlorate concentrations above 5 x 10(-6) mol L-1. The accuracy of the results was confirmed by the analysis of the contaminant in a certified reference water sample.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
11