A novel approach to determine estrogenic hormones in swine lagoon wastewater using the QuEChERS method combined with solid phase extraction and LC/MS/MS analysis

Abstract

A novel approach is reported to quantify estrone (E1), 17β-estradiol (βE2), 17α-estradiol (αE2), estriol (E3), and 17α-ethynylestradiol (EE2) in storm water runoff and swine lagoon wastewater samples. A considerable amount of residue was collected when lagoon wastewater samples were centrifuged therefore both resulting residues and aqueous portions were analyzed separately. A modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was utilized to efficiently extract the target analytes in the residue. Aqueous portions were pre-concentrated using solid phase extraction (SPE). A simple liquid–liquid extraction in a test tube was carried out as a sample clean-up step after SPE. This approach is inexpensive and requires only 3 mL of organic solvent per analysis. The resulting extracts were further purified using a dispersive solid phase extraction (dSPE) technique (not required in storm water analyses). βE2 and E1 glucuronide and sulfate conjugates were also analyzed in the aqueous portions of the lagoon samples as well as in the storm water runoff samples. An enzymatic hydrolysis was performed prior to SPE to deconjugate conjugated estrogens. Samples were derivatized with dansyl chloride to enhance LC/MS/MS analytical sensitivity. Insignificant matrix effects (1–12%) were determined for the analyses of aqueous samples. Thus, matrix matched calibration curves were not required. Matrix effects for residue analyses ranged from 14 to 20%, requiring that matrix matched calibration curves be used for quantification. All developed methods gave 84–106% recoveries for free estrogens and 65–86% recoveries for estrogen conjugates. The LODs for lagoon wastewater and storm water analyses ranged from 0.9–2 ng L⁻¹ and 0.3–0.5 ng L⁻¹, respectively. The developed methods were validated by analyzing eighteen lagoon water samples and twenty six storm water samples in three replicates.