A new macrocyclic polystyrene-based sensor for chromium (III) ions

Abstract

A new tetradentate dihydrogen perchlorate macrocyclic ligand (2,4,9,11-tetraphenyl-1,5,8,12-tetraazacyclotetradeca-1,4,8,11-tetraene dihydrogen perchlorate) was prepared and characterised. The macrocycle behaves as a selective chelating ion-exchanger for some metal ions. The polystyrene-based membrane electrode is found to exhibit quite promising selectivity for Cr3+ ions. It can be used to estimate chromium concentrations in the range 3.16x 10(-6)-1.00x10(-1) M with a near-Nernstian slope of 17.5 mV per decade of concentration between pH 3.0 to 6.5. The electrode is found to possess a fast response time of 15 s and was used over a period of three months with good reproducibility (s = +/- 0.3 mV). The selectivity coefficient values for mono-, di- and trivalent cations indicate excellent selectivity for Cr3+ ions over a large number of other cations. Anions such as Cl- and SO4(2-) do not interfere and the electrode also works satisfactorily in a mixed organic-water solution. The sensor has been used as an indicator electrode for the potentiometric titration of Cr3+ with EDTA. The practical utility of the membrane sensor has also been demonstrated in solutions contaminated with detergents (CTAB and SDS). Above all, the membrane sensor has been very successfully used to determine Cr3+ in some foods.

Carbon composite–PVC based membrane coated platinum electrode for chromium determination

“…In addition due to the vital importance of chromium (III) in many biological and industrial samples, the need for new selective and sensitive PVC-membrane electrodes is a challenging goal [3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

A comparative study of chromium(III) ion-selective electrodes based on N,N-bis(salicylidene)-o-phenylenediaminatechromium(III)

“…A number of ISEs based on PVC membrane [3][4][5][6][7][8][9][10][11][12][13][14][15][16], and coated wire electrodes [17][18][19] employing different neutral ionophores, have been made for determination of chromium ion. To our best knowledge, no carbon paste electrode for the detection of Cr ions has been reported to date.…”

Chromium(III) Ion Selective Electrode Based on Oxalic Acid Bis(Cyclohexylidene Hydrazide)

“…The reported chromium selective electrodes are based on Aliquate 336 S À Cr(SCN) 4 À ion pair [9], 8-quinoline-dithiocarboxilate [10], chromium dithizonate [11], (2,4,9,11-tetraphenyl-1,5,8,12-tetraazacyclotetradeca-1,4,8,11-tetraene dihydrogen perchlorate) [12], macrocyclic compound [13], 4-methylaminazobenzene [14], glyoxal bis (2-hydroxyanil) [15] and 2,3,8,9-tetraphenyl-1,4,7,10-tetraazacyclododeca-1,3,7aene [16]. However, these sensors suffer from the disadvantages of significant interferences from some cation, deviation from Nernstian behavior, small linear range, narrow pH range and high limit of detection.…”