Development and Validation of Colorimetric and RP-HPLC Methods for the Determination of Formaldehyde in Cosmetics

Abstract

Aims: To develop and validate two assay methods for the determination of total and free formaldehyde content in cosmetics by Colorimetric and High Performance Liquid Chromatographic (HPLC) methods, respectively. Study Design: Colorimetric and HPLC methods. Place and Duration of Study: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Dhaka, Dhaka-1000, Bangladesh; between February 2012 and June 2013. Methodology: In Colorimetric method the quantitation was performed by a UV/Vis spectrophotometer at 410 nm and by HPLC at 345 nm and the methods were linear over the concentration ranges of 4-12 mg/L (R2=0.999) and 2-32 mg/L (R2=0.999), respectively. Based on 2, 4-dinitrophenylhydrazine (DNPH) derivatization, free formaldehyde was analyzed using a Phenomenex C18 (250 mm × 4.6 mm i. d., 5 μm particle size) column in a binary separation mode with mobile phase consisting of acetonitrile and distilled water (45:55, v/v) and flow rate of 2.0 mL/min. Results: The overall recovery rate of free formaldehyde was (95.33-98.37)±(0.29-1.6)% (RSD). Seventy five cosmetics of local and foreign brands were investigated. None of those products was labeled to contain formaldehyde. 18 products were labeled with specific formaldehyde donors (17 with DMDM hydantoin and 1 with imidazolidinyl urea). 64% of the products were formaldehyde positive among which 54% exceeded 0.05% limit of formaldehyde content for which EU dictates the mandatory formaldehyde donors labeling. The investigated amounts of the total formaldehyde and free formaldehyde were 190-5502 mg/L and 47-604 mg/L, respectively. Conclusion: The methods were found valid as per in terms of suitability, linearity, accuracy, sensitivity, ruggedness, and robustness. The formaldehyde content found in the cosmetics was highly alarming and must be addressed by the authority in an immediate basis.