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Hot Topics in Analytical & Chromatography - May 2009
In this issue, we address the following topics:
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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 |
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| 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. |
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Chiral Separation
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Achiral Separation
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| 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 |
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| 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 |
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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
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Ion suppression