scholarly journals Urinary free cortisol assessment by liquid chromatography tandem mass spectrometry: a case study of ion suppression due to unacquainted administration of piperacillin

2017 ◽  
Vol 27 (3) ◽  
Author(s):  
Elisa Danese ◽  
Gian Luca Salvagno ◽  
Alessandra Guzzo ◽  
Samuele Scurati ◽  
Cristiano Fava ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Urinary Free Cortisol ◽  
Tandem Mass ◽  
Ion Suppression ◽  
Chromatography Tandem Mass Spectrometry ◽  
Free Cortisol ◽  
Liquid Chromatography Tandem Mass

scholarly journals Validation of a High-Throughput Liquid Chromatography–Tandem Mass Spectrometry Method for Urinary Cortisol and Cortisone

2002 ◽  
Vol 48 (9) ◽  
pp. 1511-1519 ◽  
Author(s):  
Robert L Taylor ◽  
Dwaine Machacek ◽  
Ravinder J Singh
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
High Throughput ◽  
Urinary Free Cortisol ◽  
Tandem Mass ◽  
Urinary Cortisol ◽  
Chromatography Tandem Mass Spectrometry ◽  
Free Cortisol ◽  
Liquid Chromatography Tandem Mass

Abstract Background: Urinary free cortisol and cortisone measurements are useful in evaluation of Cushing syndrome, apparent mineralocorticoid excess, congenital adrenal hyperplasia, and adrenal insufficiency. To reduce analytical interference, improve accuracy, and shorten the analysis time, we developed a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for urinary cortisol and cortisone. Methods: We added 190 pmol (70 ng) of stable isotope cortisol-9,11,12,12-d4 to 0.5 mL of urine as an internal standard before extraction. The urine was extracted with 4.5 mL of methylene chloride, washed, and dried, and 10 μL of the reconstituted extract was injected onto a reversed-phase C18 column and analyzed using a tandem mass spectrometer operating in the positive mode. Results: Multiple calibration curves for urinary cortisol and cortisone exhibited consistent linearity and reproducibility in the range 7–828 nmol/L (0.25–30 μg/dL). Interassay CVs were 7.3–16% for mean concentrations of 6–726 nmol/L (0.2–26.3 μg/dL) for cortisol and cortisone. The detection limit was 6 nmol/L (0.2 μg/dL). Recovery of cortisol and cortisone added to urine was 97–123%. The regression equation for the LC-MS/MS (y) and HPLC (x) method for cortisol was: y = 1.11x + 0.03 μg cortisol/24 h (r2 = 0.992; n = 99). The regression equation for the LC-MS/MS (y) and immunoassay (x) methods for cortisol was: y = 0.66x − 12.1 μg cortisol/24 h (r2 = 0.67; n = 99). Conclusion: The sensitivity and specificity of the LC-MS/MS method for urinary free cortisol and cortisone offer advantages over routine immunoassays or chromatographic methods because of elimination of drug interferences, high throughput, and short chromatographic run time.

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