What is DiatoSorb-W?
Diatomaceous earth (DE) is a type of siliceous earth that is made up of the fossilized silica exoskeletons of single-celled algae called diatoms. It was discovered in Germany in the 1830s and since then these humble fossils have grown to play a critical role in many industries and are specified in numerous procedures including many ASTM and USP compendial methods. Since the 1960s, those using packed column methods have depended heavily on diatomaceous earth brands (e.g., Chromosorb) as the solid support material in their packed columns. These original materials worked well, but due to unpredictable availability and quality, today’s analysts face long delays and inconsistent product performance.
As a leader in packed column technology, Restek has engineered an improved, saltwater-based diatomaceous earth product called DiatoSorb-W, which is available in acid-washed (WAW), nonacid washed (WNAW), and high-performance (WHP) varieties. Restek has now replaced white Chromosorb solid support with DiatoSorb-W solid support as the diatomaceous earth used in our GC packed columns and Silcoport W columns. We now pair DiatoSorb-W solid support with our stationary phases and inert tubing types to ensure our diatomaceous earth columns provide the inertness and stability you need for all of your challenging separations. We also offer a wide variety of stationary phases on DiatoSorb-W solid support in 60/80, 80/100, and 100/120 mesh sizes for those who pack their own columns.
Why use DiatoSorb-W?
Consistent Quality and Supply—Finally, a Reliable Source for Diatomaceous Earth
Virtually unlimited in supply—but only available from Restek—new DiatoSorb-W offers a reliable alternative for packed column users. After years of dealing with white diatomaceous earth brands such as Chromosorb being in short supply, users of chromatographic grade material now have a reliable new source. Whether you need diatomaceous earth columns or custom packing materials, DiatoSorb-W products from Restek are always available and consistent in quality.
All DiatoSorb-W solid support undergoes rigorous quality testing to ensure high purity and dependable performance. QC testing includes particle size distribution, density control, and chromatographic analysis to ensure inertness and reproducibility. Every mesh size of DiatoSorb-W raw material is QC tested for particle size distribution and density to ensure it meets our stringent quality control specifications for white diatomaceous earth. Particle size distribution is important since the narrower the distribution, the more efficient a column is; for applications with closely eluting peaks, the narrow peak widths afforded by high efficiency are essential for accurate quantification. The particle size distribution of DiatoSorb-W is extremely narrow, resulting in higher efficiencies and narrower peaks than were obtained on a similar column packed with a non-DiatoSorb-W support. The basic compounds in this comparison clearly show much better resolution and peak shape on the DiatoSorb-W diatomaceous earth column than on the non-DiatoSorb column made with the same tubing and stationary phase.
To guarantee inertness, which is critical for obtaining accurate data, each batch of DiatoSorb-W is QC tested with cholesterol and 5α-cholestane so consistently superior chromatographic performance can be assured. All columns are packed with white diatomaceous earth supports coated with 3% OV-101 polymer. The packed columns made with DiatoSorb-WHP support and SilcoSmooth tubing are highly inert and clearly outperform competitor columns as demonstrated by the 5α-cholestane/cholesterol area ratios. The DiatoSorb-W column produces a ratio of nearly 1.0; whereas, scores of 1.3 and 1.6 on columns from other vendors indicate that compound adsorption is occurring due to poor deactivation and active sites in the column.
Table I: Each lot of DiatoSorb-W diatomaceous earth column solid support is tested with cholesterol and 5α-cholestane to ensure superior chromatographic performance.
(n = 9)
(n = 9)
(n = 9)
|Retention time, min (cholesterol)||3.92||0.13||3.4|
|Peak area ratio (5α-cholestane/cholesterol)||1.15||0.01||
Each lot of DiatoSorb-W diatomaceous earth column solid support is tested with cholesterol and 5α-cholestane to ensure superior chromatographic performance.
Consistent Performance Means Results You Can Trust for Critical Applications
As discussed above, all characteristics of DiatoSorb-W solid support are tightly controlled and rigorously tested. This ensures that DiatoSorb-W packed columns will work dependably for vital applications. For example, accurate solvent analysis is critical for ensuring the safety of finished pharmaceutical products as well as for controlling solvent content in waste streams. DiatoSorb-W diatomaceous earth columns are a great choice for this analysis because the high surface area of the DiatoSorb-W solid support increases the coating capacity of the polymer, resulting in a column with high efficiency that is able to separate even the most volatile solvents. The analysis of underivatized free fatty acids is another example of how DiatoSorb-W packed columns perform well for difficult applications. In this case, the high inertness of the DiatoSorb-W column allows these reactive compounds to be monitored reliably even at low levels.
Switch to DiatoSorb-W and Say Goodbye to Poor Quality and Long Delivery Times
Struggling to find a reliable supply of white diatomaceous earth? Frustrated by the high cost of long delivery times and inconsistent product quality? Save time, money, and aggravation by switching to DiatoSorb-W today. Restek’s exclusive supply of raw material and rigorous QC testing ensures that DiatoSorb-W products are consistent in quality and always available. Whether you need packed columns or custom packing materials, DiatoSorb-W diatomaceous earth provides the dependable performance you need for your packed column applications.