Liquid Chromatography Mass Spectrometry (LCMS)

 

Our instrument is an Agilent 1100 LCMS with Electrospray ionization for steroids.  This allows us to quantify steroids with greater specificity and without having to perform celite chromatography for steroid separation and subsequent immunoassay.    With LCMS, the chromatography is done online and analysis using mass spectrometry gives greater certainty of results,  overall, efficiency of analysis is increased.

 

We have validated methods for the Rhesus monkey serum for the following steroids:

 

Estrogens

Estradiol and Estrone.

Cost range $24 to $42 per injection (2008 prices). 

One injection will yield results for both, typical volume of serum used for analysis is 200 µL.

 

Steroid	Limit of Quantitation (LOQ) for 200 µL rhesus serum.	Accuracy (%)
Estradiol	10 pg/mL	102 to 109
Estrone	30 pg/mL	96 to 111

 

 

Androgens

Cortisol, Testosterone, DHEA and Androstenedione.

Cost range $21 to $36 per injection (2008 prices). 

One injection will yield results for all 4 steroids, so minimum volume for all 4 is 100 µL, typical volume of serum used for analysis is in the range 100 µL to 400 µL.

 

 

Steroid	Limit of Quantitation (LOQ) in pg/mL	Accuracy (%)
Cortisol	200	111.46 ± 4.66
Testosterone	10	103.74 ± 0.67
DHEA	200	110.46 ± 2.66
Androstenedione	10	110.15 ± 3.34