348 JOURNAL OF COSMETIC SCIENCE Table II Precision and Recovery in Cosmetic Products and Raw Materials (n = 10) Sample tested Nail polish recovery (0.05%t Shower gel recovery (0.05%) Makeup foundation recovery (0.05 % ) Surfactant recovery (0.05%) a Spiked concentration. Recovery (%) 89.00% 98.01 % 90.42% 91.18% CV% (r/ 9.5 4.1 6.3 5.6 6 CV% = 100 (Six), where S is the standard deviation and x is the observed mean of the data. The addition of an internal standard in the experiment was implemented to compensate for any undesired variation in the extraction condition, including the change of the fiber properties due to irreversible adsorption of some of the matrix components (18). This method was evaluated with respect to the linearity, run precision, limit of detection, and percent recovery. This study found a linear relationship between the amounts of form­ aldehyde-PFPH derivative adsorbed by coated SPME fiber and its concentration in the solution. The calibration curve (Figure 2) obtained by plotting peak area ratio versus concentration showed a high correlation coefficient, R2 0.999, for the formaldehyde­ PFPH derivative and accuracy, expressed in terms of the standard error of estimate, of 0.13 5 3. Table II shows the precision and recovery of various samples, including nail polish, shower gel, makeup foundation, and surfactant. Table III shows the data for the limit of detection of the current method (vide infra). During this study some interference occurred. This interference was due to the internal standard peak coeluted with compounds present in the matrix of some cosmetic prod­ ucts. To eliminate this drawback, the researchers have developed an alternative SPME method, combined with the isotope dilution mass spectrum technique, in which a stable labeled isotope analogue was employed as an internal standard. This paper was published in the journal of Chromatography A (March 2004) (19). Both methods have their advan­ tages. The present method is simple, low-cost, and can be used for routine analysis. The alternative method is more accurate and sensitive however, it is relatively more expen­ sive (labeled isotope analogues are not cheap) and GC/MS capability is also required. It has been reported by Hoshika et al. (20) and Stashenko et al. (21), that high sensitivity and selectivity can be accomplished by using an electron capture detector, resulting from the five halogen atoms on the PFPH moiety. A typical chromatogram obtained for this work is shown in Figure 3. Table III Limit of Detection (LOD) of Formaldehyde in Spiked Surfactant Analyte Formaldehyde a Spiked concentration = 15 µg/ml n = 8. LOD in current researcha (µg/ml) 0.04

HS-SPME-GC DETERMINATION OF FORMALDEHYDE 349 FID1 A, (052803B1001B0101.D) p A - 40- � · 35- J: J: Sample ID: Make-up Foundation 30- a. a. ., � � � LU 25- lei � c;i LU J: (..) a. LL 20- � lS J: OI (..) J: cxi 15- OI I N 10- - ,I 5- 0 ? I Fl 1 � {? {,1 1fl mi, Figure 3. Typical chromatogram obtained after HS-SPME of the cosmetic sample. CONCLUSION Our work has demonstrated that SPME is fast, precise, and highly sensitive, and is an alternative procedure for the determination of formaldehyde in cosmetic products such as surfactant systems, foundations, and nail-polish products. ACKNOWLEDGMENTS The authors gratefully acknowledge the technical assistance and support provided by Coty Research and Development Center and especially by Ralph Macchio. REFERENCES (1) Identification and determination of free formaldehyde, Off J. Eur. Commun., L 185/18 Oune 6, 1982). (2) C. H. Wilson, Fluorometric determination of formaldehyde in cosmetic products,]. Soc. Cosmet. Chern., 25, 67-71 (1974). (3) E. Sawicki, T. R. Hauser, and S. McPherson, Spectrophotometric determination of formaldehyde and formaldehyde-releasing compounds with chromotropic acid, 6-amino-l-naphthol-3-sulfonic acid 0-acid), and 6-anilino-l-naphthol-3-sulfonic acid (phenyl J-acid), Anal. Chem., 34, 1460 (1962). (4) P. W. West and B. Sen. Spectrophotometric determination of traces of formaldehyde,]. Anal. Chern., 153, 12-18 (1956). (5) J. Zhang, D. Thickett, and L. Green, Two tests for the detection of volatile organic acids and formaldehyde, J. Arn. Inst. Conservat., 33, 47-53 (1994). (6) Y. Hoshika, Y. Takata, Gas chromatographic separation of carbonyl compounds as their 2,4-dinitro­ phenylhydrazines using glass capillary columns,]. Chrornatogr., 120, 379-389 (1976). (7) P. W. Wu, C. C. Chag, and S.S. Chou, Determination of formaldehyde in cosmetics by HPLC method and acetylacetone method, J. Food Drug Anal., 11, 8-15 (2003). (8) M. I. Feldman, Determination of free formaldehyde in the presence of its compounds with amino acids and proteins, Biochemistry, 23, 867-872 (1958). (9) R. P. Belardi and J. Pawliszyn, The application of chemically modified fused silica fibers in the extraction of organics from water matrix samples and their rapid transfer to capillary columns, Water Poll. Res. J. Canada, 24, 179-189 (1989).