In this study, a successful micro LC-MS/MS method for the highly sensitive quantitation of desmopressin in human plasma is demonstrated. It shows how the QTRAP® 6500+ LC MS/MS system with OptiFlow™ Source coupled with a M5 MicroLC system provides reliable quantitation with high reproducibility, high throughput and minimum source optimization requirements.
Desmopressin is a synthetic analogue of vasopressin, a natural pituitary hormone with antidiuretic properties. The deamination of vasopressin in the N-terminal 1 position and the replacement of 8-l-arginine with 8-d-arginine result in the formation of desmopressin. It has a longer duration of antidiuretic activity than that of the natural hormone and is essentially devoid of other associated pharmacological effects such as vasoconstriction and contraction of smooth muscles in the uterus or in the intestine.
The sub picogram/mL quantitation of desmopressin in human plasma using an analytical flow HPLC methodology, was published in a previously described method,1 in which 1 mL human plasma was used for desmopressin quantification at 0.5 pg/mL. In this current work, the advantages of MicroLC with new MS ion source were used to quantitate the desmopressin at the same level 0.5 pg/mL in human plasma with 3.3 times less consumption of plasma samples and injecting 3.3x less volume to ensure enough sample for 5 reinjections.
Key Features of the SCIEX MicroLC-MS/MS Solution
M5 MicroLC system provides:
- microfluidic flow control for accurate flow-rates down to 1 μL/min
- trap-elute option for fast and large volume sample loading
- flexibility to couple with any microLC column.
OptiFlow™ Turbo V Source on the QTRAP® 6500+ LC-MS/MS system provides:
- easy setup with no probe or electrode position optimization
- robust performance and long electrode lifetime.
Conclusion
A micro LC-MS/MS method for the highly sensitive quantitation of desmopressin in human plasma was successfully demonstrated. The QTRAP® 6500+ LC MS/MS system with OptiFlow™ Source coupled with a M5 MicroLC system provides reliable quantitation of desmopressin at the 0.5 pg/mL level with high reproducibility, high throughput and minimum source optimization requirements. The developed MicroLC method allowed for a reduction of the amount of plasma used with a factor of 3x due to improved sensitivity compared to a previously described method1 using analytical flow LC, while achieving the same LLOQ.
Reference
1. Baghla R., Guttikar S., et al., A Sub-picogram quantification method for desmopressin in plasma using
the AB SCIEX Triple QuadTM 6500 System, SCIEX Technical Note.