Headspace µ–solid phase extraction of 1,4–dioxane and 2–methyl–1,3–dioxolane from shampoo samples in a home–mode device and large volume injection of deep eutectic solvent: Theoretical and experimental studies

In the current study, a headspace micro solid–phase extraction was developed for extraction of 1,4–dioxane and 2–methyl–1,3–dioxolane from shampoo samples. After extraction, the quantities of analytes were determined using the large volume injection method followed by gas chromatography–flame ionization detector. Octadecylsilane, menthol: formic acid deep eutectic solvent, and 1,3–dioxane were used as adsorbent, eluent, and internal standard, respectively. Under optimum conditions, linear ranges for target analytes were from 0.30 to 5000 ng mL⁻¹, and 0.43–5000 ng mL⁻¹ with correlation coefficients ≥ 0.9972. The limits of detection were 0.08 and 0.11 ng mL⁻¹ for 1,4–dioxane and 2–methyl–1,3–dioxolane, respectively. The limits of quantification were 0.28 and 0.43 ng mL⁻¹ for 1,4–dioxane and 2–methyl–1,3–dioxolane, respectively. The intra– and inter–day precisions for target analytes at the spiked level of 25 ng mL⁻¹ were ≤ 4.2%. The feasibility of the recommended procedure was successfully tested for the extraction and determination of 1,4–dioxane and 2–methyl–1,3–dioxolane in shampoo samples. The extraction recoveries were ranged from 89 to 90% with relative standard deviations<5.1%. The nature of the interactions between studied chemical species was investigated in the light of conceptual density functional theoretical calculations. As to conclude, it was seen that experimental observations are compatible with the theoretical explanations made according to “hard and soft (Lewis) acids and bases” Principle.