APPENDIX

The following recipe summarises the method for producing a standard quantity of the iodine solution:
To make ca. 1000 cm³ of Ethaline, mix 590 g of choline chloride and 530 g of ethylene glycol stirring at ca. 60°C until a clear homogenous liquid is formed.

Ethaline is stable and can be stored in glass or plastic containers for prolonged periods.

To make 100 cm³ of 0.02 mol dm-³ iodine solution for gold removal, add 0.5 g of I₂ to 100 cm³ of Ethaline, stirring at ca. 60°C.

The iodine solution can be stored in a glass container for a week.