Fast Analysis of Vanilla Extracts on the Acclaim RSLC 2-mm C18 Column

Mark Tracy, Xiaodong Liu, and Christopher Pohl, Dionex Corporation

The recent development of ultra-HPLC (UHPLC) has provided a great potential for high throughput analysis achieved using small (sub-2 μm) particle size columns at increased linear velocities. The advantage of UHPLC over conventional HPLC is increased throughput without sacrificing resolution. Despite their popularity, sub-2 μm particle columns impose practical difficulties, such as high backpressure (which often requires a UHPLC system) and susceptibility to column fouling. Thus difficulty can be overcome using 2.0 to 2.5 μm particles. This study describes an example (analysis of vanilla extract) of transferring a conventional LC method to a high-throughput method using newly developed Acclaim® RSLC 2-μm columns that are based on spherical, porous, high-purity silica particles (dp = 2 μm, pore size = 120 Å, surface area = 320 m²/g).

Experimental

Acclaim 120 C18 columns (4.6 × 150 mm, dp = 5 μm, P/N 059148, Dionex, Sunnyvale, California) and Acclaim RSLC 2 μm C18 columns (2.1 × 50 mm, dp = 2 μm, P/N 068981, Dionex) were used for the separation. Separations were performed on a modular UltiMate® 3000 RS HPLC System (Dionex) equipped with a HPG 3200 RS gradient pump, WPS-3000 RS Autosampler, TCC-3000 RS column oven, and a DAD-3000 RS detector. Chromeleon® 6.80 Chromatography Management Software (Dionex) was used for system control and data processing. Vanilla extract in 40% ethanol was purchased from a local food market.

Figure 1

Results and Discussion

The AOAC Official Method 990.25 specifies a 4.6 × 250 mm column packed with C8, 10 μm irregular particles—a column that has only about 7000 plates, and takes over an hour to run. Using a modern RP C18 column, four major components in vanilla extract (Figure 1) can be separated in 45 min (Figure 2a). After proper geometric scaling without changing mobile phase, the assay can be accelerated six-fold on a 2.1 × 50 mm RSLC 2 μm, C18 column (Figure 2b). Doubling the flow rate further accelerates the analysis twelve-fold, with no sacrifice in the quality of the chromatogram (Figure 2c).

Figure 2

Conclusion

Acclaim RSLC 2-μm columns provide a well-balanced solution for a wide range of high throughput applications. Compared to sub-2-μm particle columns, they have competitive column efficiency, excellent base performance, stable and rugged column packing, and 25–50% less backpressure. As a result, Acclaim RSLC 2-μm columns are resistant to fouling and compatible with both conventional HPLC and modern UHPLC systems, providing rapid separation solutions to a broad range of applications, including pharmaceutical, food and beverage, environmental, chemical, consumer products, etc.

Acclaim, Chromeleon and UltiMate are registered trademarks of Dionex Corporation.

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