Comparative Study of Holmium (III) Selective Sensors Based on Thiacalixarene and Calixarene Derivatives as an Ionophore

Abstract

The two chelates based on calix [4]arene and thiacalix [4]arene have been synthesized and used as neutral ionophores for preparing PVC based membrane sensor selective to Ho 3+ ion. The addition of potassium tetrakis(4-chlorophenyl)borate (KTpClPB) and various plasticizers, viz., NDPE, o-NPOE, DOP, TEP and DOS have been found to improve significantly the performance of the sensors. The best performance was obtained with the sensor no. 6 having membrane of L 2 with composition (w/w) ionophore (2%): KTpClPB (4%): PVC (37%): NDPE (57%). This sensor exhibits Nernatian response with slope 21.10 ± 0.3 mV/decade of activity in the concentration range 3.0 × 10 −8 -1.0 × 10 −2 M Ho 3+ ion, with a detection limit of 1.0 × 10 −8 M. The proposed sensor performs satisfactorily over a wide pH range of 2.8-10, with a fast response time (5 s). The sensor was also found to work successfully in partially non-aqueous media up to 25% (v/v) content of methanol, ethanol and acetonitrile, and can be used for a period of 4 months without any significant drift in potential. The electrode was also used for the determination of Ho 3+ ions in synthetic mixtures of different ions and the determination of the arsenate ion in different water samples.

Recent developments of thiacalixarene based molecular motifs

“…Gupta et al 164 developed p-tert-butyl thiacalix [4]arene 1 and de-tert-butylated thiacalix [4]arene 7 fabricated PVC-based electroactive materials for the selective detection of Cd 2+ ions with a response time of 8 s. Furthermore, compounds 17b 165 and 161 166 were used in poly(vinyl chloride) membranes for optical sensing of different cations (Fig. 43).…”

Thiacalix[4]arene Derivative as Potential Carrier for Cadmium Sensing using PVC Membrane Electrode

“…In past years, analytical chemists have shown their interest to develop the selective devices based on neutral ionic carrier for the determination of cations [5][6][7][8][9][10][11][12][13][14][15] . Ion-selective electrode (ISE) is one of them.…”