ABSTRACT
A new oxalate-selective electrode based on the complex 2,2'-[1,4-butandiyle bis(nitrilo propylidine)]bis-1-naphtholato copper(II) (CuL) as the membrane carrier was developed. The electrode exhibited a good Nernstian slope of -29.2+/-0.6 mV/decade (mean value+/-standard deviation, n=5) and a linear range of 5.0 x 10(-8) to 1.0 x 10(-1)M for oxalate. The limit of detection was 5.0 x 10(-8)M. This electrode represents a fast response time (i.e. 10-15s) and could be used for more than 3 months. The selectivity coefficients were determined by the fixed interference method (FIM) and could be used in the pH range of 2.0-7.0. It was employed as an indicator electrode for the determination of oxalate in water samples.
Subject(s)
Biosensing Techniques/instrumentation , Electrochemistry/instrumentation , Membranes, Artificial , Microelectrodes , Organometallic Compounds/chemistry , Oxalates/analysis , Water/analysis , Water/chemistry , Biosensing Techniques/methods , Electrochemistry/methods , Equipment Design , Equipment Failure Analysis , Oxalates/chemistry , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
A new salicylate-selective electrode based on the complex of (2-[(E)-2-(4-nitrophenyl)hydrazono]-1-phenyl-2-(2-quinolyl)-1-ethanone) Cu(II) as the membrane carrier was developed. The electrode exhibited a good Nernstian slope of -59.6+/-1.0 mV/decade and a linear range of 1.0 x 10(-6) to 1.0M for salicylate. The limit of detection was 5.0 x 10(-7) M. The electrode had a fast response time of 10 s and can be used for more than 3 months. The selective coefficients were determined by the fixed interference method and could be used in the pH range of 4.0 to 10.5. The electrode was employed as an indicator electrode for direct determination of salicylate in pharmaceutical and biological samples.
Subject(s)
Electrodes , Hydrazones/chemistry , Organometallic Compounds/chemistry , Polyvinyl Chloride/chemistry , Potentiometry/methods , Salicylic Acid/analysis , Membranes, ArtificialABSTRACT
A highly selective poly(vinyl chloride) (PVC) membrane electrode based on butane -2,3-dione bis(salicylhydrazonato) zinc(II) [Zn (BDSH)] complex as carrier for thiocyanate-selective electrode is reported. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrode. The sensor responds to thiocyanate in linear range from 1.0x10(-6) to 1.0x10(-1)M with a slope -56.5+/-1.1mVdecade(-1), over a wide pH range of 3.5-8.5. The limit of detection of the electrode was 7.0x10(-7)M SCN(-). Selectivity coefficients determined with fixed interference method (FIM) indicate a good discriminating ability towards SCN(-) ion in comparison to other anions. The proposed sensor has a fast response time of about 5-15s and can be used for at least 3 months without any considerable divergence in potential. It was applied as indicator electrode in titration of thiocyanate with Ag(+) and in potentiometric determination of thiocyanate in saliva and urine samples.
