Forensic Investigation of Formaldehyde in Illicit Products for Hair Treatment by DAD‐HPLC: A Case Study

Abstract

The illegal use of formalin (commercial formaldehyde) in cosmetic products harms the health of individuals exposed to this substance. Over the last years, the commercial availability of these products, especially those containing irregular dosage of formaldehyde, has increased in Brazil. This work analyzes some products for hair treatment available in the Brazilian market and verifies their safety. The adopted analytical methodology involved sample derivatization with 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography with ultraviolet detection (UV-VIS) at λ = 365 nm. The limit of quantification is 2.5 × 10 w/w, and the recovery tests were around 93%. Some of the samples contained high and illegal formaldehyde levels ranging from 9% to 19% (w/w) and others presented suitable concentrations of the analyte. On the basis of the results, this work discusses the efficiency and practicality of this analytical method for forensic purposes.

Formaldehyde analysis of seized cosmetic products by HS-GC-MS of methylal, ethoxymethoxymethane, and ethylal derivatives

“…However, very few studies have investigated formaldehyde in hair-straightening products. Oiye et al (2016) analyzed five samples of these products sold in Brazil and found two samples containing levels of 0.02 and 0.03% and three samples at levels from 9.2 to 18.4%, much higher than those found in the present study. In the United Sates, the Environmental Working Group investigated 16 companies that make hair-straightening products that are commercialized in the country (EWG, 2011).…”

“…Various analytical methods to detect formaldehyde in cosmetic and pharmaceutical products have been reported, including the semi-qualitative chromotropic acid (CA) colorimetric method (Hauksson et al, 2016;Malinauskiene et al, 2015), spectrophotometry after derivatization with acetylacetone (Brandão, Ramos, Rodrigues, 2018), HPLC-UV after derivatization with 2,4-dinitrophenylhydrazine (Golden, Valentini, 2014;Soman, Qiu, Chan, 2008;Oiye et al, 2016), HPLC separation followed by derivatization with 3,5-diacetyl-1,4-dihydrolutidine spectrophotometry (Miralles et al, 2018) and headspace-gas-chromatography (HS-GC) after derivatization with ethanol (Del Barrio et al, 2006;Daoudy et al, 2018). Under acidic conditions, methylal or ethylal can be prepared through the reaction of formaldehyde and methanol or ethanol, and etoxymethoxymethane (EMM) is formed when both alcohols are present (Cao et al, 2009;Chopade, Sharma;1997;Zhang, Zhang, Jian, 2011), as shown in Figure 1.…”

Novel Method of Analysis for the Determination of Residual Formaldehyde by High-Performance Liquid Chromatography

“…As it is crucial to reach an equilibrium before the solutions are transferred into vials for analysis, a 50-minute derivatisation was selected; this is lower than times employed by some methods in the literature [ 12 , 14 , 48 ]. If time is a critical factor, lower derivatisation times (30–35 minutes) may be employed, as shown in Figure 2 , similarly to other derivatisation methods found in the literature [ 53 , 56 , 67 ]. Standard and sample solution stability was successfully demonstrated when using this derivatisation time, as described in the “Standard and sample stability” section.…”

Natural ‘Green’ Sugar-Based Treatment for Hair Styling

“…In addition, the hydroxide and thio-based straighteners, formaldehyde and glutaraldehyde, have been actively used for hair straightening, despite having been banned due to their toxicity, simply because they are inexpensive and result in shiny, straight hair through the crosslinking of the amine groups in the keratin [6]. Formaldehyde is even more dangerous compared to glutaraldehyde as it causes serious damage to tissues and the respiratory tract of users, as well as those of the hairdressers working in salons, and has been classified as a carcinogen [6,9,12].…”