68 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table I Absorbance Ratios of the Sulfonate Oxidation Band (1042 cm-•) Against Peptide Bands for Once-Bleached Hair (Samples A) Before Subtraction After Subtraction 1042 1042 1042 1042 1042 1042 1042 Frequency (cm- •) 1076 1650 1235 1235 1650 1235 1235 (Baseline, cm -•) (--1050) (--1900) (--1100) (--900) (--1900) (--1100) (--900) Tress 1 0.727 0.011 0.058 0.041 0.023 0. 120 0.084 1.027 0.018 0.092 0.061 0.036 0. 178 0. 118 0.872 0.015 0.069 0.045 0.035 0. 163 0. 106 Tress 2 0.988 0.008 0.078 0.054 0.028 0.159 0.110 0.445 0.014 0.045 0.032 0.018 0. 102 0.072 0.838 0.015 0.071 0.050 0.029 0. 136 0.096 Tress 3 1.851 0.015 0.090 0.068 0.026 0.159 0.120 1.020 0.018 0.079 0.054 0.032 0. 143 0.098 2.634 0.030 0. 130 0.090 0.042 0. 178 0. 123 Mean 1. 156 0.016 0.079 0.055 0.030 0. 149 0.103 CV (%)* 58. ! 39.5 30.5 30.8 24.4 17.5 16.6 Corr. Coeff.** 0.15 0.37 0.62 0.63 0.60 0.82 0.85 * Coefficient of variation for 9 determinations. ** Correlation coefficient of 1042 cm-• band against peptide band intensities. Coefficients of variation were calculated from the ratios in Tables I and III to determine the precision of triplicate analyses within each tress and the variability between replicate tresses. Representative values are shown in Table IV. While considerable variability was found between fibers of the same tress, the variability between the triplicate means Table II Absorbance Ratios of the Oxidation Band (1042 cm-2) After Subtraction Against Peptide Bands for Once-Thioglycollate-Waved Hair (Samples B) 1042 1042 1042 Frequency, (cm- •) 1650 1235 1235 (Baseline, cm- •) (-- 1900) (-- 1100) (--900) Tress 1 Tress 2 O.OO79 O.O225 0.0073 O.OO67 0.0035 O.OO93 Tress 3 0.0057 0.0085 0.0129 Mean 0.0094 CV (%)* 59.4 Corr. Coeff.** 0. 569 0.045 0.032 0.126 0.081 0.039 0.024 0.033 0.024 0.021 0.013 0.055 0.039 0.026 0.018 0.053 0.036 0.069 0.048 0.052 0.035 61.1 57.6 0.561 O.593 * Coefficient of variation for 9 determinations. ** Correlation coefficient of 1042 cm-• band versus peptide band intensities.

FOURIER TRANSFORM INFRARED SPECTROSCOPY OF HAIR 69 Table III Ratios of the Oxidation Band (1042 cm-l) and Bunte Salt Band (1022 cm-l) After Subtraction Against Peptide Bands for Once-Bisulfite-Waved Hair (Samples C) 1042 1042 1042 1022 1022 1022 Frequency (cm- l) 1650 1235 1235 1650 1235 1235 (Base/ine) (--1900) (--1100) (--900) (--1900) (--1100) (--900) Tress 1 --0.012 --0.076 --0.059 0.021 0.133 0.104 0.005 0.026 0.017 0.012 0.056 0.037 --0.002 --0.012 --0.008 0.014 0.078 0.051 Tress 2 --0.004 --0.016 --0.011 0.022 0.084 0.056 0.015 0.074 0.049 0.023 0.113 0.076 --0.003 --0.019 --0.011 0.013 0.085 0.050 Tress 3 0.008 0.043 0.028 0.023 0.116 0.077 O. 006 O. 027 O. 018 O. 020 O. 086 O. 058 --0.002 --0.011 --0.007 0.009 0.060 0.040 Mean 0.006 0.034 0.023 0.017 0.090 0.061 CV (%)* -- -- -- 30.9 28.7 34.5 Corr. Coeff. ** -- -- -- 0.305 0.642 0.616 Coefficient of variation for 9 determinations. Correlation coefficient of 1022 cm-• band versus peptide band intensities. of replicate tresses was low. The variability between analyses within tresses was about 20% for bleached hair and about 32% for Bunte salt hair. C¾'s between means of replicate tresses was 10-14% for bleached hair and only 4-9% for Bunte salt hair. These results show that three analyses are sufficient for obtaining reproducible oxidation values. Table IV Coefficients of Variation (%) of Absorbance Ratios From Table i Col/•mn 5 Cobiron 7 1042 cm- • 1042 cm- • Bleached Hair 1650 cm- • 1235 cm- t Tress 1 23 17 Tress 2 24 21 Tress 3 24 12 Means of Three Tresses 14 10 From Table III Column 4 Column 5 1022 cm- 1 1022 cm- t Bunte Salt Hair 1650 cm-• 1235 cm-t Tress 1 30 45 Tress 2 28 18 Tress 3 42 32 Means of Three Tresses 9 4