Capillary Column-Gas Chromatographic Determination of Menthol in Contact Lens Solution

Sample of cornea contact lens solution was ultrasonically extracted with ethyl acetate, centrifuged and the supernatant was used for GC determination. DB-Wax capillary column (30 m×0.32 mm, 0.5 μm) was used for separation. FID and internal standard method were adopted in the determination. Linearity range of menthol found was between 3.74 and 187.2 mg·L-1, with detection limit (3S/N) of 0.15 mg·L-1. The proposed method was applied to the determination of menthol in cornea contact lens solution, giving values of recovery and RSD′s (n=6) in the ranges of 98.3%-99.3% and 0.72%-1.95% respectively.