Methods for Quantifying Toxic Preservatives in Hair Care Products

Despite formaldehyde being a known carcinogen, it is frequently used in cosmetic products as a preservative due to its antimicrobial properties. The FDA lists formaldehyde (FA) and formaldehyde releasers (FR) as common allergens in cosmetic products. According to the European Union, up to 2000 ppm of formaldehyde is permitted in cosmetics but quantifying free formaldehyde from formaldehyde releasers in cosmetics can be challenging.² Formaldehyde releasers work by releasing formaldehyde over time through hydrolysis reactions. They are often added to cosmetics to prevent the growth of microbial species. Examples of formaldehyde releasers include 1,2-Dimethylol-5,6-dimethylhydantoine (DMDM hydantoin), diazolidinyl urea, quatanerium-15, bronopol, etc. Effective analytical methods are important for regulating formaldehyde concentrations in cosmetics and especially hair products. However, the methods for quantifying formaldehyde are not directly suitable for quantifying free formaldehyde produced from formaldehyde releasers - the traditional techniques facilitate an increase in the release of formaldehyde, thus altering the actual concentration.¹ Generally, a form of derivatization is used to increase the sensitivity for the detection of free formaldehyde produced from formaldehyde releasers with spectrophotometric techniques. Free formaldehyde from formaldehyde releasers in hair products can be quantified through extraction, derivatization, and spectrophotometry. The following techniques are effective for quantifying free formaldehyde from formaldehyde releasers: reversed-phase dispersive liquid–liquid microextraction (RPLLME), gas-diffusion microextraction (GDME), and ultrasound-assisted cloud point extraction (UA-CPE) followed by spectrophotometric analysis.^1-3 This seminar will show that the RPLLME method paired with LC-UV/Vis analysis has the most sensitivity in measuring formaldehyde released from formaldehyde releasers in hair products.

References

1. Brandão, P. F.; Ramos, R. M.; Rodrigues, J. A. GDME-Based Methodology for the Determination of Free Formaldehyde in Cosmetics and Hygiene Products Containing Formaldehyde Releasers. Anal. Bioanal. Chem. 2018, 410 (26), 6873–6880.

2. Miralles, P.; Chisvert, A.; Alonso, M. J.; Hernandorena, S.; Salvador, A. Determination of Free Formaldehyde in Cosmetics Containing Formaldehyde-Releasing Preservatives by Reversed-Phase Dispersive Liquid–Liquid Microextraction and Liquid Chromatography with Post-Column Derivatization. J. Chromatogr. A 2018, 1543, 34–39.

3. Temel, N. K.; Gürkan, R. Combination of Ultrasound-Assisted Cloud-Point Extraction with Spectrophotometry for Extraction, Preconcentration, and Determination of Low Levels of Free Formaldehyde from Cosmetic Products. J. AOAC Int. 2018, 101 (6), 1763–1772.