Notification of Shodex Out-of-spec Products and Their Replacements

Resonac Corporation
Functional Chemical Division

Dear valued customers,

Thank you for purchasing and using Shodex products.

We notify that it has been revealed that some Shodex products manufactured in the past had errors in the inspection item "asymmetry factor (Fas)" which describes the separation ability of the product. The cause was that when inspection analysis software was updated, wrong Fas calculation formula was applied and the mistake was not realized. The result of recalculation confirmed that some products were not meeting the required specification.

We will provide new product that meeting the required specifications to replace the corresponding products. Please access below Shodex web site and check if you have any of the corresponding products with mentioned serial numbers. If you have the corresponding product, please kindly follow the “Request Form” and fill in the required items. Then, we will arrange to send you replacement product(s) to the registered address.

We sincerely apologies for the inconvenience this may have caused. We will endeavor to strengthen the quality control to prevent the similar mistakes to reoccur and provide you reliable products that satisfy your analytical needs.

Corresponding period

2017 – 2021

To request the replacement

Please fill-in the required items in "Request Form for Shodex Column Replacement".

Corresponding products

Please click the product name to check the serial number.

  • Note:The serial number follows "No." on the product tag attached to the product body, "S/N" on the product outer box label, or "Column number" on the CoA. Please check the 8-digit characters.

Details on out-of-spec products

Fas is an index that measures the left-right symmetry of peak shapes in chromatograms. The peak symmetry reflects the uniformity of packing material in HPLC columns. Especially when the packing material is filled sparse (non-uniformly filled) in the flow direction, the base of the peak spreads to front or back, and thus symmetry will decrease. For two peaks that elute at similar timings, if their bases are wide, they may overlap with each other. This may alter their peak area calculations, and consequently leads to incorrect quantification results. Therefore, Fas is one of the important factors when evaluating the separation ability of HPLC columns.
Concerning peak symmetry, there are two major indexes. One is asymmetry factor (Fas) which is recommended by ASTM International, the world's largest organization of standards. Another one is symmetry factor (S) which is recommended by the United States Pharmacopeia. They are defined below.

For Shodex products, as described on the Shodex homepage and product instruction manuals, “Asymmetry Factor” should had been adopted, however “Symmetry Factor” had been mistakenly applied during the stated period. The result of recalculation confirmed that some products were not meeting the required specifications, but released for sales.

Measures to prevent recurrence

The Fas formula in the analysis software have been revised and corrected to the ones that should had been applied. We will provide you replacement columns meeting the required specifications and ask you to return the out-of-spec product at our expense of the shipment. We again apologies for the inconvenience this may cause.