244 JOURNAL OF COSMETIC SCIENCE 1300 900 - 600 - 3oo- -75 0.0 1300 9oo_ E • 600- ,.• 300- -75 oo 1300 900- g600- "• 300- OA la I I I 16u -25 15.0 30.0 45.0 57.0 Retention time (min) 0.0 NNO I 2a I I 15.0 30.0 45.0 57.0 Retention time (min) 15.0 30.0 44.0 Retention time (min) 160 113 I 213 .•1oo I -25 I I o.o 15.o 30 o 44.0 Retention time (rain) lc o.o 15.o 30.0 45.0 57 o Retention time (rain) Figure 4. Successive chromatograms of four matrix product samples before and after extraction. 1: OA 2: NNO 3: ORA 4: DMDM. a: Before extraction. b: After a one-step extraction. c: After a two-step extraction. (See text for experimental data and abbreviations.) obtained are reported in Table VI. The complete extraction of BHT in a two-step extraction procedure was confirmed, and the extraction protocol has also been shown to be efficient for isolating LDA, TDS, CC, and DC from the sample. Nevertheless, once

MATRIX COMPOUNDS AND OXIDATIVE HAIR DYES 245 1300 ORA 3_•a 6OO- 300_ -75 0.0 150 30.0 45.0 57 0 Retention time (min) 1300 9OO- 600- 300- -75 0.0 3b I 15.0 30.0 45 0 57.0 Retention time (min) -50 0.0 -50 0.0 100 50 0.0 Figure 4. Continued DMDM 4a I I I 7.5 15 0 22.5 30 0 Retention time (mln) 4b I I I 7.5 150 22.5 30.0 Retention time (min) 4_qc 7.5 15.0 22.5 30.0 Retention time (min) more, it has to be noted that the efficiency of the extraction protocol varies slightly, depending on the matrix product. LDA and TDS need a one-step extraction procedure to be fully extracted, while the complete extraction of CC and DC involves a three-step extraction procedure. Moreover, NOL, LS, SS, TEA, and PQ are not at all extracted.