1991 Volume 32 Issue 6 Pages 559-563_1
An ion chromatographic method was developed for the determination of ferrocyanide in wine. Hydrogen cyanide, which was produced from ferrocyanide by heating and addition of 10% sulfuric acid (3ml) to wine (30ml), was entrained by nitogen gas into a trapping solution containing 0.1N sodium hydroxide. A modified Rankine apparatus was used. Then the trapped solution was directly subjected to ion chromatography with electrochemical detection.
The cyanide ion derived from ferrocyanide was separated under basic solvent conditions (4mM ethylenediamine, 20mM sodium bicarbonate and 100mM sodium hydroxide) on a column of Tosoh DEAE-5PW Glass at a flow rate of 1.2ml/min at 40°C. It was detected by a Tosoh EC-8000 detector with a silver working electrode at 0mV (determination limit: 0.5ppb as cyanide anion). The recoveries of various amounts of ferrocyanide (50-1, 000ng/ml calculated as Na4Fe(CN)6 in wine) added to white and red wine were 88-130%. The presence of additional Na2SO3 (688μg/ml wine) did not interfere with the measurement of the recoveries.
The described method is very sensitive (determination limit: 1ng/ml calculated as Na4Fe(CN)6 in wine), so that the background level of cyanide (less than 5ppb as cyanide anion in the trapped solution) could be observed in various kinds of wine bottled in Japan. Since a trace of cyanide was also detected in musts for wines, it is likely that the cyanide in wine is naturally occurring.
