Studies on Analysis of Food Additives (XII)

Abstract

The control standard method was applied to the assays for 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (abbreviated as furylfuramide) and nitrofurazone.The procedures are as follows:FURYLFURAMIDEReagent:Control standard solution: Weigh accurately about 0.1g of potassium bichromate, dissolve in 0.01N sulfuric acid and make exactly to 1000ml.Sample solution:Weigh accurately about 0.1g of furylfuramide, dissolve in 40ml of dimethylformamide and dilute with water exactly to 1000ml. Dilute 10ml of this solution with the mixture of 0.05M KH2PO4 solution and 0.05M Na2HPO4 solution (9:1, pH6.0) to 100ml. The volumetric flask used should be colored, because furylfuramide solution is very sensitive to light.Determination:Determine the absorbance of the control standard solution (As), at the wave length of absorption minimum (about 313mμ). At the same time determine the absorbance of the sample solution (A), at the wave length of absorption maximum (about 308mμ).Calculation:Content(%)=A/As×0.842×Weight of potassium bichromate(g)/Weight of furylfuramide(g)×100NITROFURAZONEReagent:Control standard solution: Weigh accurately about 0.1g of potassium bichromate, dissolve in 0.01N sulfuric acid and make exactly to 1000ml. Dilute 25ml of this solution with 0.01N sulfuric acid to 100ml.Sample solution:Weigh accurately about 0.1g of nitrofurazone, dissolve in 40ml of dimethylformamide and dilute with water exactly to 1000ml. Dilute 5ml of this solution with the mixture of 0.05M KH2PO4 solution (9:1, pH6.0) to 100ml. The volumetric flask used should be colored, because nitrofurazone solution is very sensitive to light.Determination:Determine the absorbance of the control standard solution (As), at the wave length of absorption maximum (about 257mμ). At the same time determine the absorbance of the sample solution (A), at the wave length of absorption maximum (about 261mμ).Calculation:Content(%)=A/As×0.947×Weight of potassium bichromate(g)/Weight of nitrofurazone(g)×100