171 UV FILTERS IN SUNSCREEN PRODUCTS Figure 4. Chromatogram of standard solution. Figure 5. Chromatogram of placebo. Figure 6. Chromatogram of sample solution.

172 JOURNAL OF COSMETIC SCIENCE Method precision (repeatability). The precision of a method is defined as “the closeness of agreement between a series of measurements obtained from multiple sampling of the same homogenous sample under the specified conditions.” Precision was assessed by preparing six sunscreen samples and analyzing them using the proposed approach. Both the system and method precision results indicated that the approach is precise within acceptable ranges. For both solutions, the SD and RSD were computed all the findings were within the acceptable limits. For the RSD, acceptable precision was less than 2.0% (Tables II and III). y = 131604x - 109307 R² = 0.9975 0 500000 1000000 1500000 2000000 0 2 4 6 8 10 12 14 CONCENTRATION(PPM) Average Area vs Concentration Figure 7. Linearity curve for octinoxate. y = 57467x - 79915 R² = 0.9974 0 500000 1000000 1500000 0 5 10 15 20 25 30 Average Area vs Concentration Figure 8. Linearity curve for octocrylene. y = 73287x - 48710 R² = 0.9911 0 200000 400000 600000 800000 1000000 0 5 10 15 Average Area vs Concentration Figure 9. Linearity curve for benzophenone-3. AVERAGEAREA