Wei Zou (Presenter)
California Department of Public Health
Bio: Dr. Zou has been working as a research scientist at California Department of Public Health. He has more than 10 years of hands-on experience on different types of LC-ESI/APCI/ICP-MS and GC-MS. His current interest is multidimensional online SPE and 2-D comprehensive LC-MS.
Authorship: Wei Zou, Jianwen She
Environmental Health Lab Branch, California Department of Public Health
| Short Abstract In the current study, a 2-D online SPE method has been developed to reduce matrix effects, and therefore, to improve limit of detection (LOD). We found out that the second dimension SPE helped to reduce the matrix effects significantly. |
Long Abstract
Bisphenol A (BPA) has been shown to have endocrine activity and may affect the fetus and infant, including possibly causing changes in development and behavior. California enacted legislation banning the use of BPA in baby bottles and sippy cups, which was to be effective July 1, 2013. However, as of July 2012, the U.S. Food and Drug Administration permanently ended the use of BPA in these products. Manufacturers are considering BPA analogs or derivatives as replacements for BPA in various applications, such as epoxy resins used as protective linings in food cans and in thermal paper. BPA analogs or derivatives could leach into food or be transferred from paper products, leading to human exposure. Targeted screening of these compounds in urine will provide an indication of human exposures to these emerging compounds. In the present study, bisphenol S (BPS), bisphenol B (BPB), bisphenol F (BPF), bisphenol AF (BPAF), and other commercially available BPA analogs or derivatives were analyzed. These compounds were selected for study based on potential for exposure in the U.S., in vitro or in vivo tests showing endocrine activity, and other factors. Because these compounds may be present in human urine at ppb or sub-ppb levels, a highly sensitive method is needed for human biomonitoring studies.
Previously, we developed a one-dimension online solid phase extraction (SPE) method to automate LC-MS sample preparation. The 1-D online SPE protocol was optimized for maximal absolute recovery rates and high throughput. However, we noticed strong matrix effects even after sample cleaning up with a C18 SPE column. In the current study, a 2-D online SPE method has been developed to reduce matrix effects, and therefore, to improve limit of detection (LOD). We found out that the second dimension SPE helped to reduce the matrix effects significantly. Method accuracy and precision and robustness were validated using in-house made quality control (QC) materials for initial demonstration of capability (IDC) and using performance test samples from US Center of Disease Control (CDC) for inter-laboratory validation. A set of anonymous human samples were analyzed as a pilot study.
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