130 JOURNAL OF COSMETIC SCIENCE column (250 mm by 4.6 mm ID), both obtained from Altech Chromatography (Deer- field, Illinois). The analytical column was housed in a thermostatted column compart- ment at room temperature. Chromatographic separation was achieved using a solvent program starting initially at 50% water, 34% acetonitrile, 13% 2-propanol, and 3% methanol that was changed linearly over 35 minutes to 15% water, 55% acetonitrile, 25% 2-propanol, and 5% methanol, and held at the final composition for an additional ten minutes. The mobile phase flow rate was 1.0 ml/min. The mobile phase was gradually returned to the initial mobile phase composition over a period of ten minutes. Phthalate esters were detected at 230 nm. QUANTITATION Four-point calibration curves were prepared for each phthalate ester. Phthalates were identified in sample extracts by comparing HPLC retention times with standards, and quantitated using the standard calibration curve for each phthalate ester. Sample extracts were diluted as necessary to confirm that the concentrations were in the linear range of the calibration curve. Calculated phthalate ester concentrations of 10 ppm or less were recorded as not detected. RECOVERY The recovery of phthalate esters from cosmetic products was determined by fortifying products with 100 and 1,000 ppm of each ester followed by extraction and HPLC analysis as described above. RESULTS AND DISCUSSION In this study, a rapid method for the determination of five phthalate esters was developed and validated. For most cosmetic sample extracts, each phthalate ester was completely separated from other components by HPLC and could be quantitated unambiguously. To further confirm that observed peaks were due to phthalate esters and not impurities, UV spectra of chromatographic peaks were evaluated to determine peak purity. For DMP it was generally necessary to use peak UV spectra to distinguish DMP from other compounds eluting near the retention time of DMP. HPLC calibration curves obtained for BBP, DBP, and DEHP were found to be linear over the concentration range of 0.001 mg/ml to 1 mg/ml. The calibration curve for DMP was linear from 0.001 mg/ml to 0.3 mg/ml, while DEP was linear from 0.001 mg/ml to 0.6 mg/ml. All regression correlation coefficients were better than 0.995. The limit of quantitation (LOQ) ranged from 1 to 10 ppm at ten times baseline noise. Figure 1 shows the chromatographic separation of the five phthalate esters and typical chromato- grams of cosmetic extracts. The presence of phthalate esters in solvents, laboratory equipment, and plastic materials has been reported by other investigators. To assure accurate quantitation of phthalate esters in the cosmetic products examined, laboratory equipment and glassware were carefully washed and thoroughly rinsed with water and ethanol before use. The HPLC

PHTHALATE ESTERS IN COSMETIC PRODUCTS mAU- 3000 _ a) Standard 2500- 2000- 1500- 1000- 500- o__,___ ___� mAU 2500 2000 1500 1000 0 (b)Nail Ena DMP DEP 10 DMP BBP DBP 20 30 131 DEHP 40 min 500 0---+---�--' �-���-�------�� 0 mAU (c) Fragrance 3000 2500 2000 1500 1000 0 mAU 3000 (d) Nail Enamel 2500 2000 1500 0 10 DEP 10 10 20 30 40 min 20 30 40 min DBP 20 30 40 min Figure 1. HPLC chromatograms of (a) phthalate ester standards, (b) nail enamel, (c) fragrance product, and (d) nail enamel.