Picolinic acid → Cobalt fluoride picolinic acid

Reagents and Standards Preparation. Emulsion blank was prepared from 20 mL of phosphate buffer (pH 7.5), 2 mL of decane, and 10 drops of Tween 20 by emulsifying using a homogenizer. This blank was used to dissolve emulsion samples as well as for dilution. 2 mL of methyl linoleate and 10 drops of Tween 20 were added into 20 mL of 2.81 mM DHR-6G, and emulsified using a homogenizer to prepare 2.1 μM DHR-6G working solution in emulsion condition. 0.015 g of cobalt fluoride and 0.0219 g picolinic acid were dissolved in 40 mL of 75 mM phosphate buffer (pH 7.4) to give cobalt fluoride/picolinic acid working solution. Hydrogen peroxide solution was prepared by mixing 12.5 mL of 30% hydrogen peroxide and 7.5 mL of deionized water. Vitamin E standard solution was prepared by emulsifying 2 mL of deionized water, 0.2 mL of 18.60 mM Vitamin E solution, and 1 drop of Tween 20.