Ethanol R1, Absolute

Ethanol R1, Absolute Ethanol R1

Absolute ethanol grade of commerce complying with the following test.

Methanol Not more than 0.005% v/v when determined in the following manner. Carry out the method for gas chromatography, Appendix III B, alternately injecting 1 µL of the following solutions three times. For solution (1) use the reagent being examined. For solution (2) dilute 0.5 mL of anhydrous methanol to 100 mL with the reagent being examined and further dilute 1 mL to 100 mL.

The chromatographic procedure may be carried out using a glass column (2 m × 2 mm) packed with ethylvinylbenzene- divinyl benzene copolymer (75 µm to 100 µm) and using 30 mL per minute as the flow rate of the carrier gas. Maintain the temperature of the column at 130°, that of the injection port at 150° and that of the detector at 200°. After each injection heat the column to 230° for 8 minutes.

Calculate the percentage of methanol using the expression ab/(c – b) where a is the percentage v/v content of methanol in solution (2), b is the area of the methanol peak in the chromatogram obtained with solution (1) and c is the area of the methanol peak in the chromatogram obtained with solution (2).