Steroid Assay Development Nightmare – Analytes in Every Sample and Everywhere Katerina Sadilkova (Presenter) Seattle Children’s Hospital Presenter Bio: Katerina Sadilkova received her PhD in organic chemistry from Charles University in Prague, Czech Republic. After conducting a restauration of state and religious documents for Czech Royal Archive, she continued as an analytical and organic chemistry research scientist at Cornell University, University of California Davis, and University of Washington. After a few years of mass spectrometry experience in the biotech industry, she moved to Seattle Children’s Hospital. Here she helped to introduce liquid chromatography-mass spectrometry technology into clinical laboratory and developed multiple clinical tests using this technique for therapeutic drug monitoring as well as for measurement of biological metabolites critical for human health.

Authors: Katerina Sadilkova (1), William Lace (1), Jane Dickerson (1, 2)
(1) Seattle Children’s Hospital, Seattle, WA, (2) University of Washington, Seattle, WA

In the early stages of testosterone and 17-hydroxyprogesterone steroid assay development, analytes of interest started suddenly appearing in every sample, including solvent blanks and zero volume injection samples.

First, we ruled out several LCMS hardware parts (column, tubing, MS divert valve). Then, after several days of intense investigation, we found out that the contamination was coming from both aqueous and organic mobile phases. The contamination continued to appear in varying amounts as we prepared several fresh batches of mobile phases.

We realized that the contamination appeared after we weighed powder standards of testosterone and 17-hydroxyprogesterone in the lab next to LCMS reagents preparation area. It had spread throughout the space and we had to go through multiple cleaning cycles as well as develop rigorous solvent preparation and testing procedures to prevent it in the future.

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