LLE–GC–MS Determines Polycyclic Aromatic Hydrocarbon Levels in Disposable Baby Diapers

A team of researchers in Gdańsk, Poland has investigated the presence of polycyclic aromatic hydrocarbons (PAHs) in disposable diapers that can pose threats to exposed babies (1) and to the landfill and runoff environments where disposable diapers are accumulated. Quantitation of various PAHs was achieved by gas chromatography coupled to mass spectrometry (GC–MS) preceded by a liquid-liquid extraction (LLE) sample preparation method that was optimized in two ways: by the selection of chloroform, dichloromethane, and diethyl ether as solvents, and in the “salting out” process of adding sodium chloride to the aqueous phase.

Baby legs and bottom in diaper on bed | Image Credit: © Prostock-studio - stock.adobe.com

PAHs pose significant environmental and health hazards. These compounds are formed during incomplete combustion of organic materials, such as fossil fuels, wood, and tobacco. PAHs are persistent in the environment and can be found in air, water, soil, and various consumer products. Exposure to PAHs has been linked to adverse health effects, including cancer, reproductive disorders, respiratory problems, and developmental abnormalities. PAHs can enter the human body through inhalation, ingestion, or skin contact. Additionally, PAHs are toxic to aquatic organisms and can bioaccumulate in the food chain, posing risks to ecosystems. Given their widespread presence and potential harm, monitoring and minimizing PAH exposure is crucial for protecting both human health and the environment.

Published in the Journal of Chromatography A, this study sampled 20 individual disposable diapers of different commercial brands purchased in drugstores and grocery stores in Poland. Prior to extraction, the diapers were immersed in liquid nitrogen for 2 min and then homogenized under cryogenic conditions for 5 min, which rendered them in a powdered state (1). The research team described it as the first time disposable diapers have been used as a “challenging analytical matrix” for compound extraction.

In this experiment, the researchers aimed to devise what they called a “harmonized analytical method” for determination of compounds such as PAHs, which are known to have deleterious health effects, in sanitary products for children (1). PAHs and other volatile organic compounds are among the chemicals that may cause certain harms, such as dermatitis, to the skin of babies, according to the researchers. The study said the safety standards of the self-regulating diaper industry, at least in Poland, do not cover all dangerous substances, and that while most brands do not contain all 15 PAHs, there are no makers who have eliminated them completely.

Optimization of the sample preparation in this study, as mentioned, considered two factors: extracting solvent and salt concentration (1). With respect to the latter, the method of “salting out” by adding sodium chloride to the aqueous phase of liquid-liquid extraction (LLE) was compared in terms of extraction efficiency at 5%, 10%, and 15% of the solution, with efficiency at its most reproducible and relative standard deviations (RSD) the smallest at 15%.

Further parameters were set with limits of detection in the range of 0.041 ng/g to 0.221 ng/g for fluorene and fluoranthene, two of the PAHs, respectively, with both of those being well below levels thought to be hazardous to children (1). Chrysene, another PAH, registered the lowest concentration (and is not detected in most diapers anyway), but the concentration of acenaphthene ranged from 1.6 ng/g to 362.4 ng/g. According to the National Institutes of Health, acenaphthene is a water-insoluble compound, derived from coal tar, that is used in pharmaceuticals, dyes, insecticides and fungicides, and plastics manufacturing. The researchers suggest acenaphthene may be photomutagenic, which means exposure to it at the same time as sunlight could be harmful.

Even considering that alarming finding, the study said that all 15 PAHs detected were “significantly lower” than the 0.5 mg/kg concentration limit proposed in 2018 by the European Chemical Agency (ECHA) (1). But the researchers urged continued emphasis on PAH monitoring, to better minimize these compounds’ negative effects on humans and the environment.

Reference

(1) Georgiev, P.; Belka, M.; Bączek, T.; Płotka-Wasylka, J. The presence of polycyclic aromatic hydrocarbons in disposable baby diapers: A facile determination method via salting-out assisted liquid-liquid extraction coupled with gas chromatography–mass spectrometry. J. Chromatogr. A 2023, 1698, 463981. DOI: 10.1016/j.chroma.2023.463981