Survey of Organosilicone Compounds, Including Cyclic and Linear Siloxanes, in Personal-Care and Household Products

The determination of organosiloxanes in consumer products is important for the evaluation and characterization of sources of human and environmental exposures. In this study, we determined concentrations of cyclic siloxanes [octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6)], tetradecamethylcycloheptasiloxane (D7)] and linear siloxanes (L4 to L14) in a variety of consumer products (n = 76), including hair-care products, skin lotions, body washes, cosmetics, nursing nipples (i.e., pacifiers), cookware, and household sanitation products such as cleansers and furniture polishes, using gas chromatography–mass spectrometry with selected ion monitoring. Prior to the analysis of samples, a method was developed to reduce the contamination arising from organosiloxanes present in certain gas chromatograph (GC) parts, such as the inlet septum; use of a Restek BTO septum at an inlet temperature of 200°C gave the lowest background level (D4: 0.8 pg; D5: 0.3 pg; D6: 0.2 pg). Concentrations of cyclic siloxanes in consumer products analyzed ranged from <0.35 to 9380 μg/g, from <0.39 to 81,800 μg/g, from <0.33 to 43,100 μg/g, and from <0.42 to 846 μg/g for D4, D5, D6, and D7, respectively. Concentrations of linear siloxanes varied from <0.059 to 73,000 μg/g. More than 50% of the samples analyzed contained D4, D5, or D6. Cyclic siloxanes were predominant in most of the sample categories; D5 was predominant in hair-care products, skin lotions, and cosmetics; D6 or D7 was predominant in rubber products, including nipples, cookware, and sealants. Potential daily exposure to total organosiloxanes (sum of cyclic and linear siloxanes) from the use of personal-care products by adult women in the United States has been estimated to be 307 mg. Significant positive correlations (p < 0.01) existed in our study between D4 and D7, D4 and linear siloxanes, D5 and D6, and D5 and linear siloxanes. The correlations can be related to the composition of organosiloxanes used in consumer products. The results of our study suggest that a wide variety of consumer products that are used on a daily basis contain cyclic and linear siloxanes and these products can contribute considerably to human exposures.