Challenges in Analyzing 7 Hormones in Drinking Water System Using Automated SPE and LC/MS/MS

Oral Presentation

Prepared by L. Sanchez, M. Wehner, L. Yoo
Orange County Water District, 18700 Ward Street, Fountain Valley, CA, 92708, United States


Contact Information: Lsanchez@ocwd.com; 714-378-3344


ABSTRACT

Contaminant of Emerging Concerns (CECs) are consistently discovered in water reuse and drinking water supply systems in recent years - concern about the presence of the CECs in the environment and groundwater prompted federal mandated program; UCMR3, using EPA Method 539 to look for 7 hormone compounds Androstenedione, 17b-Estradiol, Estriol, Estrone, 17a-Ethyneylestradiol, Equilin and Testosterone. EPA 539 is one of the three UCMR 3 methods that use Solid Phase Extraction (SPE) for sample preparation. During the method developing period, Initial Demonstration of Capacity (IDC) study, we found that EPA 539 is not only challenging in sample preparation but also in sample analysis. We tried manual extraction procedure many times and failed before switched to the automated SPE that produced better % recovery, higher accuracy and consistent results over all. We overcome many issues with samples preparation before we fine tune EPA 539 and passed IDC criteria. Also, due to the requirement of low detection limits in part per trillion (ppt) or ng/L, we had to acquire a new LC/MS/MS instrument; a high end Liquid Chromatography Tandem Mass Spectrometry to analyze the targets. This positive-negative ion switching instrument is able to detect the lowest concentration of 0.10 ng/L for Testosterone using a single injection with 16 minutes analysis. Its a significant achievement for Advanced Water Quality Assurance Laboratory to bring on line EPA 539 and certified to support the UCMR 3 program for 19 groundwater producers in Orange County, CA.