Toiletries Products Testing

Razavi, Nourolhoda, and Zarrin Es' haghi. Microchemical Journal 148 (2019): 616-625.

Parabens are widely used preservatives in personal care products, including toothpaste, but their potential health concerns necessitate accurate detection methods. This study employed dispersive magnetic solid-phase extraction (DMSPE) using curcumin-loaded magnetic graphene oxide (CUR-MGO) as a sorbent, followed by high-performance liquid chromatography with photodiode array detection (HPLC-DAD), to extract and quantify four paraben species in toothpaste and mouthwash samples.

The CUR-MGO sorbent was synthesized and confirmed through FT-IR, VSM, SEM, TEM, and EDS analyses. The extraction parameters were optimized using univariate analysis and experimental design. The method demonstrated excellent linearity (0.001–5 μg/mL, R² = 0.9938–0.9993), with detection limits as low as 0.0004 μg/mL and enrichment factors between 36 and 55. Precision assessments confirmed the method's reliability, with satisfactory repeatability and reproducibility.

Application of this optimized method revealed that all tested toothpaste samples contained methyl paraben, confirming its prevalence as a preservative. Propyl paraben was also detected in most samples. Relative recoveries ranged from 71.62% to 120.34%, validating the method's accuracy. These findings emphasize the necessity of monitoring preservatives in oral care products to ensure consumer safety and regulatory compliance. The DMSPE-HPLC-DAD method offers a rapid, sensitive, and environmentally friendly approach for routine analysis of parabens in toothpaste formulations.

Torres, Briyitte Sofa S., et al. "Potentially Toxic Elements in Commercial Soap and Powder Detergent Samples." Journal of the Brazilian Chemical Society 35.4 (2024): e-20230164.

The presence of heavy metals in personal care products, including soaps, can pose significant health risks, making their accurate quantification crucial. In this study, the determination of cadmium (Cd), magnesium (Mg), lead (Pb), and zinc (Zn) in liquid and bar soaps, as well as a powder detergent, was conducted using inductively coupled plasma optical emission spectroscopy (ICP-OES) following different sample preparation methods.

Three digestion techniques—dry decomposition, wet digestion, and dissolution in aqueous medium—were evaluated, with wet digestion using 1 mol L^-1 HNO₃ and 30% H₂O₂ found to be the most efficient for sample preparation. The concentrations of the metals were found to be below detection limits for Cd and Pb, with Mg levels ranging from 50.89 to 1119 µg/g and Zn from 280.25 to 537.54 µg/g. The average hydrodynamic diameter of the particles was 525 nm, measured using dynamic light scattering.

The method's accuracy was verified through recovery tests, achieving values between 83% and 119%, with a relative standard deviation (RSD) ≤ 4.30%. The limits of detection (LOD) ranged from 0.015 to 0.5 µg/g, ensuring reliable and sensitive detection. The results confirm that the soaps and detergent samples analyzed are within safe limits, as defined by regulatory standards, ensuring their safety for consumer use.

Gaubert, Alexandra, et al. Analytical and bioanalytical chemistry 408 (2016): 4669-4681.

The increasing demand for environmentally friendly laundry detergents has driven the replacement of synthetic surfactants with bio-sourced alternatives and enzymatic formulations. However, accurately identifying and quantifying these enzymes remains a challenge due to the complex detergent matrix. This study applied a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze protease, amylase, cellulase, and lipase in commercial laundry detergents.

To overcome the interference from high surfactant concentrations, a specialized sample preparation protocol was developed. The method utilized selected reaction monitoring (SRM) mode for both light and heavy peptides, ensuring high specificity and sensitivity. The calibration curves demonstrated excellent linearity within the ranges of 25–1000 ng/mL for protease, lipase, and cellulase; 50–1000 ng/mL for amylase; and 5–1000 ng/mL for cellulase in detergent matrices.

The application of this technique successfully enabled enzyme identification and absolute quantification in commercial laundry detergents. This is the first study to achieve such precise detection in a single analytical run. The findings provide critical insights into detergent formulation, ensuring quality control, regulatory compliance, and improved performance of enzyme-based detergents. The developed method serves as a valuable tool for manufacturers to optimize laundry detergent compositions while meeting sustainability requirements.