260 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table I DRIFTS and AA Data on Hair Fibers Sample Hair mg/kg Si 1260 • 1260 • 1240 no. ref. AA 1240 1225 1225 1 K14.17 0 0.58 0.68 1.17 2 K1.31 0 0.74 0.80 1.08 3 K14.2 402 1.38 1.60 1.16 1.22 2.37 1.94 4 K14.15 580 1.78 1.72 0.97 5 K95.1 350 1.48 1.46 0.99 6 K95.7 270 1.36 1.61 1.19 7 K1.23 1840 2.46 3.61 1.46 3.36 4.12 1.23 8 K6.25 1555 2.49 3.06 1.23 2.76 3.12 1.13 9 K6.26 1190 3.13 4.40 1.41 2.502 2.722 1.092 10 K6.27 1040 1.972 2.702 1.372 2.212 2.452 1.112 11 K14.7 1460 2.93 4.22 1.44 3.97 5.59 1.41 2.982 3.802 1.282 12 K95.2 430 1.44 1.63 1.14 1.58 1.76 1.11 13 K95.8 260 1.25 1.52 1.22 14 K14.14 1060 1.94 2.70 1.39 15 K95.3 180 0.91 1.13 1.24 16 K14.8 550 1.67 1.54 0.92 17 K14.4 180 0.73 0.73 0.99 DRIFTS conditions of 0.2 g KBr/0.05 g hair for 1-min grinding time. Exception to •conditions, used 1.5-min grinding time. may be unique for two reasons: 1) the close proximity of the particular bands selected for ratioing, and 2) surface rather than bulk analysis. CONCLUSIONS Use of diffuse reflectance with FTIR has been evaluated as a siloxane-specific detector for keratin fibers. Methodology was developed for qualitative detection of siloxanes using spectral subtraction techniques and quantitative detection using the band ratio technique. Hair fibers are non-reflective and require mixing with a reflective material therefore, KBr was selected. A sample preparation procedure was defined involving a 4:1 KBr/hair ratio with a total sample weight of 0.25 g and a grinding/mixing time in a WIG-L-BUG for one minute. These conditions are optimum for surface analysis of the fiber. Longer grinding times and higher KBr levels lead to greater homogeneity of the sample but result in bulk rather than surface analysis. A series of treated hair samples was available on which the weight concentration of Si had been measured by atomic absorption. The siloxane polymer used to treat the hair

SILOXANES ON KERATINS BY FTIR 261 5.5 5 4.5 n-' 3.5 Z 3 [] 2.5 I- 2 n- 1.5 1 , ß 1260/1240 RATIO ß 200 400 600 800 1000 1200 1400 1600 1800 mg/kg Si by AA 5.5 O 4.5 I-- 4 n- 3.5 z 3 (/) 2.5 I.L. 2 t"l 1.5 [] 1260/1225 RATIO 200 400 600 800 1000 1200 1400 1600 1800 mg/kg Si by AA Figure 11. Correlation of DRIFTS and mg/kg Si by AA--hair data.