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Formaldehyde in hair straightening products: Rapid 1 H NMR determination and risk assessment
Author(s) -
Monakhova Yulia B.,
Kuballa Thomas,
Mildau Gerd,
Kratz Evamaria,
KeckWilhelm Andrea,
Tschiersch Christopher,
Lachenmeier Dirk W.
Publication year - 2013
Publication title -
international journal of cosmetic science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 62
eISSN - 1468-2494
pISSN - 0142-5463
DOI - 10.1111/ics.12027
Subject(s) - formaldehyde , chemistry , dilution , hydrolysis , analytical chemistry (journal) , nuclear chemistry , chromatography , organic chemistry , physics , thermodynamics
Synopsis Despite official regulations, the illegal use of formaldehyde‐containing or releasing hair straightening products has become a popular practice in Europe and high contents of formaldehyde in such products have been reported. In this study, a methodology utilizing 1 H NMR spectroscopy has been developed to measure the concentration of formaldehyde in hair straightening products. For sample preparation, a dilution and alkaline hydrolysis is required. The total formaldehyde content can then be quantified by a distinct peak of the CH 2 group of the methanediol molecule in the δ4.84–4.82 ppm range. The developed methodology was applied for the analysis of 10 hair straightening products. Seven of these products contained detectable amounts of formaldehyde that were higher than the maximum allowed concentration of 0.2%. The formaldehyde content of these products was found to be in the range 0.42–5.83% with an average concentration of 1.46%. The accuracy and reliability of the NMR results were confirmed by the EU reference photometric method. The air formaldehyde concentrations after application of hair straightening products were estimated in ranges 20–423 ppm and 1–18 ppm (for 1 and 24 m 3 salon volume). A probabilistic exposure estimation using Monte Carlo simulation found the average formaldehyde concentration to be 6 ppm (standard deviation 15 ppm). All exposure scenarios considerably exceeded the safe level of 0.1 ppm. Our findings confirmed that the risk of cosmetic formulations with formaldehyde above 0.2% is not negligible, as these products may facilitate considerable exposure of formaldehyde for consumers especially for salon workers.