osy 65 35 blend of nomex t 462 and fr rayon plain weave fabric and fabric 2 is a 6 osy nomex t 462 plain weave fabric table i permethrin owf permethrin owf permethrin owf fabric after treatment after 10 launderings after 20 launderings fabric 1 0 70 0 55 0 51 fabric 2 0 41 0 41 0 39 amounts of insect repellant on the fabric were determined using gas chromatography such as the glc method of analysis for permethrin in technical material and formulations available from the mclaughlin gormley king company as an example one possible test method for determining the amount of permethrin incorporated into the fabric uses a gas chromatograph equipped with a flame ionization detector the column is 5 ov 1 on chromosorb w hp 80 100 mesh 120 cm u00d7 4 mm i d glass the column temperature is 250 u00b0 c and the injection port and detector temperatures are each 300 u00b0 c gas flows are n 2 at 50 mls min air at 240 mls min and h 2 at 60 mls min the flame ionization detector has a sensitivity of 5 u00d7 10 u2212 11 afs the method is as follows a sample of permethrin in acetone is prepared such that the amount of permethrin in the acetone is approximately 1 0 mg ml a standard solution comprising 1 0 mg ml of permethrin in acetone is also prepared the sample and standard solution each further comprise one equivalent.