Hot Topics in Analytical & Chromatography - May 2009

In this issue, we address the following topics:

• Ion suppression
• Warfarin analysis
• Sample retrieval

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Ion suppression - Phospholipid and protein contamination are two of the leading causes of ion suppression when analyzing biological fluids via LC-MS/MS HybridSPE™-Precipitation is a new sample prep platform that combines the simplicity of protein precipitation and the selectivity of SPE for the targeted removal of proteins and phospholipids from biological plasma

Features and Benefits of HybridSPE-PPT

• 2-3 step generic procedure
• 100% removal of phospholipids & precipitated proteins
• Minimal-to-no method development
• Available in 96-well & 1 mL cartridges
• Ideal for high-throughput pre-clinical and clinical studies
• Patent-pending technology

For more information, visit the HybridSPE-PPT web page.

ESI-MS of Clenbuterol Enantiomers in Rat Plasma Extracted with HybridSPE-PPT Showing No Phospholipid Interference
Conditions
Column:	CHIROBIOTIC T, 10 cm x 2.1 mm, 5 µm (12018AST)
Mobile phase:	10 mM ammonium formate in methanol
Flow rate:	0.3 mL/min.
Det.:	ESI(+); MRM: 184/104 m/z (phospholipids) and 277.2/203.1 (clenbuterol)
Temp.:	30 °C
Injection:	10 µL
Sample:	10 ng/mL Clenbuterol in rat plasma

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Warfarin - This popular anticoagulant is in the news because of recent research1 showing a large variation in human phenotypes that can lead to dangerous over- or under-dosing. Warfarin is supplied as a racemic mixture. Astec CHIROBIOTIC™ V2 columns separate warfarin enantiomers, while Ascentis® RP-Amide is ideal for the achiral analysis.

Chiral Separation		Achiral Separation
Conditions Column: Astec CHIROBIOTIC V2, 25 cm x 4.6 mm I.D, 5 µm particles (15024AST) Mobile Phase: (40:60) 10 mM ammonium acetate, pH 4.1:methanol Flow: 1 mL/min. Detection: UV at 230 nm Temp.: 25 °C		Conditions Column: Ascentis RP-Amide, 15 cm x 4.6 mm I.D, 5 µm particles (565324-U) Mobile Phase: (85:15) 1% acetic acid:methanol Flow: 1 mL/min. Detection: UV at 230 nm Temp.: 35 °C

Additional Information:
¹ Takeuchi F, McGinnis R, Bourgeois S, Barnes C, Eriksson N, et al. (March 2009) A Genome-Wide Association Study Confirms VKORC1, CYP2C9, and CYP4F2 as Principal Genetic Determinants of Warfarin Dose. PLoS Genet 5(3): e1000433.

Astec CHIROBIOTIC Chiral HPLC Columns
Ascentis HPLC Columns

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Sample retrieval - When conventional vials and poorly designed vial inserts limit retrieval of samples, analytical capabilities are reduced, making sample retrieval a hot topic. Sometimes the most important or complex analysis can be encumbered by the simplest element of the analytical process. The patented Center Draining (CD) vial has a unique, conical interior well that allows the contents to completely drain to the center of the vial so you can analyze the entire sample.

Features and Benefits of CD vials 

• Center drain design maximizes sample volume retrieval
• Popular dimension - compatible with any autosampler that uses 12 mm x 32 mm vials
• Large vial opening eliminates bent needle problems associated with limited volume inserts
• Useful when the amount of sample is limited
• Concentrate and analyze samples in the same vial
• Type 1 borosilicate glass, -70 °C to 160 °C temperature range

Additional Information:
Visit sigma-aldrich.com/vials
View the Center Drain (CD) Vials excerpt from Reporter 26.5