Which of the following is used for preservation of alcohol?

(Sodium fluoride) Sodium fluoride is a useful preservative in a suspected case of alcohol poisoning. It is done with mixing 10 mL of blood with potassium oxalate & sodium fluoride (enzyme inhibitors) for suspected alcohol poisoning. A preservative (sodium fluoride, 0.5 -2% weight by volume) should be added after collecting a vitreous humour sample for ethanol analysis in postmortem toxicology cases. Gastric contents can be stored in saturated salt solution.