Disposable Pipette Extraction (DPX) Coupled to HPLC-DAD as an Alternative for the Determination of Phthalic Monoesters in Urine Samples

Abstract

Phthalates are widely used in industry, but adverse effects on human health have been reported due to exposure to these chemicals. In the human body, they are metabolized into phthalic monoesters, which are used to monitor human exposure and assess risk. Urine is one of the main biological samples used, due to its easy access and collection, and also being the main elimination pathway for phthalates. Urine samples are complex; therefore, sample preparation is a critical step. Disposable pipette extraction (DPX) has not previously been reported for quantifying phthalates in urine and is here presented as a fast and low sample consumption method. A fully optimized RP-DPX method was developed for determination of free monomethyl phthalate, monobutyl phthalate, monobenzyl phthalate, and monoethylhexyl phthalate from urine samples. Analytical parameters of merit were obtained. The values of R2 were ≥0.9832, and the LOD and LOQ varied from 3.0 to 7.6 μg L−1 and 10 to 25 μg L−1, respectively. Intraday (n = 3) and interday (n = 9) precision were ≤13.6 and 15.6%. The accuracy, as relative recovery, presented a range from 83 to 120%. The method was robust after performing the Youden test. Compared to other methods, this work stands out due to its short extraction time and sample consumption.