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Hot Topics in Analytical & Chromatography - April 2009
In this issue, we address the following topics:
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 Biodiesel - Escalating costs, unstable supply and environmental impact of fossil fuels have spurred global interest in biodiesel and made it an analytical hot topic.
The Supelco MET-Biodiesel capillary GC column was designed specifically for the reliable determination of free and total glycerin in B100 biodiesel samples. |
| Peak IDs |
| 1. |
Glycerin |
| 2. |
Butanetriol (I.S.) |
| 3. |
Monopalmitin (C16:0) |
| 4. |
Monoolein (C18:1), Monolinolein (C18:2), Monolinolenin (C18:3) |
| 5. |
Monostearin (C18:0) |
| 6. |
Tricaprin (I.S.) |
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| Conditions |
| Column: |
MET-Biodiesel, 14 m x 0.53 mm I.D., 0.16 µm with integrated 2 m x 0.53 mm I.D. guard (28668-U) |
| Oven: |
50 °C (1 min.), 15 °C/min. to 180 °C, 7 °C/min. to 230 °C, 30 °C/min. to 380 °C (10 min.) |
| Det.: |
FID, 380 °C |
| Carrier Gas: |
helium, 3.0 mL/min. |
| Injection: |
1 µL, cold on-column |
| Sample: |
B100 Biodiesel plus Butanetriol Internal Standard (44896-U) and Tricaprin Internal Standard (44897-U), derivatized with MSTFA (394866) then diluted in heptane |
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Addtional Information:
For complete methodology on determination of glycerin and moisture in B-100 biodiesel, please refer to Bulletin 943
Visit sigma-aldrich.com/biofuels to see all our product lines for this application.
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 Melamine - A food adulterant used to inflate nitrogen content, melamine became an analytical hot topic when it was found in food, including baby formula.
Ascentis Express HPLC columns and Discovery SPE tubes combined with MS detection permit low-level detection and high recoveries of melamine from milk. |
| Conditions |
| Column: |
Ascentis Express HILIC, 10 cm x 2.1 mm I.D., 2.7 µm particles (53939-U) |
| Mobile Phase: |
10 mM ammonium formate in (A) 90:10 and (B) 70:30 acetonitrile:water |
| Gradient: |
0-100% B in 5 mins. |
| Flow: |
0.2 mL/min. |
| Detection: |
MS/MS; MRMs (127/85 and 127/68). MRM 127/85 was used for quantitation. |
| Injection: |
2 µL |
| Sample: |
whole milk spiked with melamine (100 ng/g) and extracted with Discovery DSC-SCX SPE tubes (52688-U) |
| Standards: |
Melamine solution, 100 µg/mL in 50:50 acetonitrile:water (44642-U); Melamine standard, ≥ 99.0% (52549) |
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Addtional Information:
Full procedure including column wash steps and the SPE method can be obtained from Technical Report T408188.
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 Acetonitrile - The global shortage of acetonitrile, an important HPLC mobile phase component, has made creative ways to reduce its use an analytical hot topic.
Supelco has responded to this important analytical need by providing practical techniques, instrument adaptation and unique HPLC column technology. |
This might be the time to explore Ascentis Express columns. Solvent savings as high as 75% can be realized by converting a conventional method to Ascentis Express.
In addition to Ascentis Express, switching to methanol and changing mobile phase and instrument settings can have significant impact.
Additional Information:
To learn more, view our detailed Technical Report and literature below, or contact Technical Services (phone: 814-359-3041) to guide you through these options.
 Product Information :
Save Acetonitrile with Ascentis Express HPLC Columns (T409033) |
 Technical Report:
Approaches to Lessening the Impact of the Acetonitrile Shortage on Your Reversed-Phase HPLC Separations (T409034) |
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