SUNNYVALE, Calif. (Dec 2011)—Thermo Fisher Scientific is pleased to announce a new method that allows sialic acids in five representative glycoproteins to be determined by acid hydrolysis release and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD). Application Update 180: Direct Determination of Sialic Acids in Glycoprotein Hydrolyzates by HPAE-PAD demonstrates that determination of Nacetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) on a Thermo Scientific Dionex CarboPac PA20 Fast Sialic Acid column is specific and direct. After sample hydrolysis or enzymatic treatment, there is no need for further sample derivatization. This new approach separates Neu5Ac and Neu5Gc with a total analysis time of 16.5 min, which is faster than previous methods, allowing greater sample throughput. Disposable gold on polytetrafluoroethylene (Au on PTFE) working electrodes with a four-week lifetime simplify system maintenance compared to conventional gold electrodes.

Sialic acids are critical in determining glycoprotein bioavailability, function, stability, and metabolism. Consequently, glycoprotein sialylation, and the identity of the sialic acids, play important roles in therapeutic protein efficacy, pharmacokinetics, and potential immunogenicity.

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