Orbitrap Illustration

Ten Steroid Panel

Quantitation of endogenous steroids or similar molecules in body fluids is challenging due to their low levels, the interfering matrix, the small volumes of sample and the presence of many similar compounds in the sample. SRM analysis using a triple quadrupole LC-MS/MS system has been routinely employed for quantitative analysis of these analytes. Although, in many cases, SRM offers the desired sensitivity and specificity, some key assays still suffer from interferences and a lack of robustness. High-resolution, accurate mass spectrometry based on Orbitrap™ technology offers for the first time an attractive alternative with the unique benefits of specificity, sensitivity and, more importantly, ease of use. Ultra-high resolution of up to 140K FWHM and better than 3 ppm mass accuracy on both precursor and fragment ions help minimize interferences due to isobaric precursor ions and fragment ions obtained in a collision cell (isobaric for triple quadrupole MS/MS or any unit resolution instrument).
 
Here we describe the quantitative workflow solutions for vitamin D metabolites, testosterone and other steroids, estrogens and cholesterol.

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Workflow Overview for the Ten Steroid Panel

 
Quantitative analysis of wide ranging steroids in human serum is challenging due to low endogenous levels, the presence of many similar molecules and matrix interferences. An SRM-based analysis needs significant sample preparation. The challenge to achieve the desired sensitivity and dynamic range comfortably is further aggravated by the water losses during ionization with both electrospray ionization and APCI sources and the extensive fragmentation in the collision cell.
 
The workflow described here uses simple full-scan MS at 100,000 FWHM resolution. The data is acquired in Full Scan mode and the quantitation is based on extracted ion chromatograms using a 3 ppm window around the m/z of interest. This application demonstrates the capability of the Thermo Scientific Exactive Plus MS coupled to a uHPLC system for quantitative analysis of ten steroids.



 



resources

 

Quantitative analysis of Testosterone in plasma using Q Exactive

He K, Kozak M.
Slide Presentation

 

 

Quantitation of Testosterone Using Q Exactive Mass Spectrometer - Comparison of APCI, APPI and HESI Sources

He K, Kozak M.
Slide Presentation

 

Sensitive determination of prohibited drugs in dried blood spots (DBS) for doping controls by means of a benchtop quadrupole/Orbitrap mass spectrometer 

Thomas A, Geyer H, Schänzer W, Crone C, Kellmann M, Moehring T, Thevis M.
Anal Bioanal Chem. 2012 May;403(5):1279-89.
 

 

Evaluation of quantitative performance for testosterone analysis in plasma on a novel quadrupole Orbitrap mass spectrometer

He K, Kozak M.
ASMS 2011 Poster