Development of an Air-assisted Dispersive Liquid-Liquid Microextraction Method as a Valuable Biomonitoring Tool for Exposure Assessment of Phthalates

In recent years, the number of epidemiological studies on phthalates that can inform and help update health risk assessments has grown rapidly. Developing reliable and rapid analytical methods for determining phthalate monoesters (m-PAEs) is an important biomonitoring tool for assessing exposure. In this study, a fast and sensitive method was developed to determine 15 m-PAEs in human urine samples as effective biomarkers for exposure assessment. Air-assisted dispersive liquid-liquid microextraction and liquid chromatography coupled to mass spectrometry were used. In order to determine the optimal conditions and model the variables influencing the extraction efficiency, a central composite rotatable design coupled with response surface methodology was used. Under the optimized conditions, the method achieved good linearities (R > 0.99), satisfactory intra- and inter-day accuracies (97–111%), and intra- and inter-day precision (RSD < 14%). The proposed procedure allowed the detection of the m-PAEs with limit of detection values between 0.02 and 0.10 ng mL-1, which makes the method sensitive and appropriate for assessing internal exposure to phthalates. The applicability of the proposed procedure was evaluated by screening fifty children’s urine from Brazil. High detection frequencies and urinary concentrations of several m-PAEs associated with using personal care products and diet were found.