Ion exchange material and method of making same

Abstract

Abstract Cations in solution are determined by loading with said cations an ion exchange strip comprising a b -cellulose film impregnated with an indicator dye containing arylsulphonic groups, washing the strip, elutriating the loaded ions and determining the concentration of the elutriated ions conventionally, e.g. by flame photometry or compleximetric titration. Elutriation may be performed with, e.g. 0.05N HCl or 5% w/v NaCl. The strips may be regenerated and reused, and can be employed in dirty situations: reference is made to determining calcium in blood serum. The preferred Congo red strips may be prepared by impregnating the b -cellulose film at 80-85 DEG C in a bath of up to 0.5% w/v Congo red in water/propane-1:2-diol for at least 30 mins., washing, converting to the blue form with HCl and to the red form with aq. NaHCO3, washing, allowing to stand in CO2-free low conductivity water until leaking ceases, drying and cutting into strips.ALSO:Sheets of water-permeable b -cellulose, e.g. regenerated cellulose, may be dyed with Congo red by immersing at 80-85 DEG C in a bath of up to 0.5%w/v Congo red in water/propane -1:2-diol for at least 30 mins., washing the sheet, converting to blue form with HCl, converting to red (sodium) form with aq. NaHCO3, washing in high purity water and allowing to stand in CO2-free low conductivity water until the dye ceases to leak from the sheet and drying. The resultant sheets are cut into strips for analytical use (see Division B1). The final wash water may contain 8% propane-1:2-diol to prevent excessive rigidity.

Inventors

• 👤 Leslie D Macleod

Bibliographic Details