Craig Aurand (Presenter)
Merck
Bio: Craig Aurand is the Innovation Manager for the Advanced Analytical division of Merck KGaA. Craig’s primary role is identification and development of innovative analytical techniques for life science applications. He is responsible for the development of innovative chromatographic and sample preparation devices for life science application, and has published numerous presentations and publications focusing on novel chromatographic separations and sample preparation techniques. Craig has more than 15 years’ experience in product and applications development with emphasis in liquid chromatography mass spectrometry techniques. His most recent research has focused on the field of micro sampling techniques in bioanalysis.
Authorship: Craig Aurand, Anders Fridstrom, Emily Barrey, Candace Price, Sara Smith
Merck KGaA, Darmstadt, Germany
| Short Abstract The extraction mechanism for Biocompatible Solid Phase Micro Extraction (Bio-SPME) enabled for the determination of unbound testosterone and some of its metabolites at low levels by LC/MS/MS. Improved sample preparation techniques allowed for reproducible and accurate quantitation of the unbound/bound analytes in human and animal serum samples. Advantages over current methodologies concerning matrix interference removal and pre-concentration of the analytes to achieve low detection limits will be presented. |
Long Abstract
Immunoassay (IA) and ELISA approaches for total (bound + unbound) steroid determination are typically hindered due to the lack of specificity of antibodies for the measurement of the particular steroids. With the wide acceptance of LC/MS/MS in the clinical setting, there is a growing trend toward converting traditional IA techniques toward more specific and robust LC/MS/MS approaches. Though LC/MS/MS improves assay specificity and allows of multiplexed analyte assays to be conducted simultaneously, it is not without limitations specifically toward interference from endogenous sample matrix. LC/MS/MS assays can often be hindered by ionization effects from the endogenous matrix from biological samples. This can result in random and arbitrary discrimination in analyte responses. In addition to the typical total testosterone methods, methods for the determination of bioavailable or unbound testosterone have been developed to improve clinical diagnostics for specific disorders associated with levels of testosterone and other steroids.1
In this study, Bio-SPME fibers were used to determine the unbound concentrations for testosterone, 6β-hydroxytestosterone, DHT, androstenedione, 17α methyltestosterone, 17-OH Ppogesterone, DHEA, 11-deoxycortisol and 21-deoxycortisol in human and calf serum samples. Removal of matrix components like phospholipids enabled for detection and quantitation at pg/mL levels for most of the compounds. Total testosterone was evaluated using simple protein precipitation as well as protein precipitation with phospholipid removal to demonstrate improvements observed by removing phospholipids. Accuracy, precision, limits of quantitation, and matrix factors will be presented and discussed. Bio-SPME proved to be an accurate and precise method for the determination of unbound testosterone and metabolites at low levels.
References & Acknowledgements:
1. Mayo Clinic http://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/83686 (Accessed July 2016)
| Description | Y/N | Source |
| Grants | no | |
| Salary | yes | Merck KGaA |
| Board Member | no | |
| Stock | no | |
| Expenses | no |
IP Royalty: no
| Planning to mention or discuss specific products or technology of the company(ies) listed above: | yes |