GC-MS determination of phthalate esters in human urine: A potential biomarker for phthalate bio-monitoring.

Six phthalic acid esters (PAEs) in human urine sampled randomly from three districts (Erode, Thanjavur, and Perambalur) in Tamil Nadu State and a Union Territory (Pondicherry) in India were quantified. We determined gender-wise, age-wise and location-wise distribution of PAEs and measured estrogenic activity of urine by molecular docking. Bis(2‑ethylhexyl) phthalate (DEHP) was the predominant phthalic acid ester found and had a recovery of 104.5% (ultrasonic extraction at 15 min). Gender-wise (pregnant women: 185 ng/mL, children: 156 ng/mL, female: 151 ng/mL, and male: 138 ng/mL), age-wise (1-20 y: 157 ng/mL, 21-40 y: 156 ng/mL, and >40 y: 146 ng/mL), location-wise (urban: 154 ng/mL, and rural: 151 ng/mL), and region-wise (Erode district: 185 ng/mL, Thanjavur district: 155 ng/mL, Perambalur district: 117 ng/mL, and Pondicherry: 135 ng/mL) differences with total mean of Σ6 PAEs were found. The molecular docking study showed a high negative binding energy of PAEs with microbial receptors. Based on the results we conclude that urine could be used as an ideal biomarker to understand PAEs exposure in humans.