Abstract

Romteera Chueachot, Saksit Chanthai^*

DOI : http://dx.doi.org/10.13005/ojc/300115

Trace analysis of cyanide (CN) based on the absorbance of the catalytic reaction of ninhydrin (NH) in the presence of CN^- was developed. This reaction was investigated consisting of 0.08 M NH, 0.4 M Na₂CO₃, 1% (v/v) Tween 20 and 2.5 M NaOH in 5-mL final volume. The absorbance of the CN-NH complex was measured against the reagent blank at 598 nm. The calibration curve was widely linear over the range of 40-160 µg/L with r² >0.99. The method recoveries of free cyanide, bound cyanide and total cyanide for wine samples were found in the range of 76.2-89.2%, 73.2-91.2% and 76.8-94.8%, respectively, at 250 µg/L CN^- spiked level. Limit of detection was 6 µg/L. The reproducibility of the proposed method was less than 4.44%. This method was then applied for local Thai fruit wines. No trace amount of cyanide was detected, as if high recovery (88.4%) of the micro-distillation was guaranteed. The obtained results were in agreement with those of the chloramine-T/barbituric acid-pyridine method with no statistically significant difference at 95% confidence level.

Cyanide; Wine; Ninhydrin; Micro-distillation; Chloramine-T/barbituric acid-pyridine

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