Analysis of Surfactants Quantification and Characterisation by Charged Aerosol Detectors (CAD) in Combination with Liquid Chromatography (LC) (CAT#: STEM-B-0370-CJ)

After the separation step by high performance liquid chromatography (HPLC), the column eluate is atomized by a stream of nitrogen and the mobile phase is evaporated along with other volatile components. In the case of CAD, the analyte particles are then positively charged by the secondary nitrogen stream. Final detection of these dried particles (all non-volatile) is performed by light scattering (photomultiplier tube) or charge level (electrostatic meter) of the CAD, respectively.

LC-CAD combined with product-specific sample preparation protocols to remove proteins is the mainstay used for polysorbate quantification. According to the LC protocol, the major subclasses of polysorbates are resolved and degradation kinetics can be followed in a straightforward manner.

Biopharmaceutica

1, Nebulization
Charged Aerosol Detection begins by nebulizing the column eluent into droplets and subsequently drying the droplets into particles. The particle size increases with the amount of analyte.
2, Charging
A stream of ionized nitrogen gas collides with the analyte particles in the mixing chamber. The charge transfers from the ionized gas to the analyte particles—the larger the particle, the greater the charge.
3,Detection
The charged particles transfer to a collector, where an extremely sensitive electrometer measures the aggregate charge. This process generates a signal directly proportional to the mass of the analyte present.

• Sample: Surfactants (such as: integral part of biopharmaceutical formulations), polysorbate 20 (PS20), polysorbate 80 (PS81), Buffer excipients (such as: amino acids or saccharides), Small molecule APIs
• Equipment: Charged Aerosol Detector (CAD), Liquid Chromatography (LC) instruments

• The quality requirements for pharmaceutical grade polysorbate 20 and 80 are specified in the different pharmacopoeias. For polysorbate 80, the Chinese Pharmacopoeia describes the strictest regulations for the fatty acid composition and requests an all-oleate polysorbate (≥ 98%), whereas the European and US pharmacopoeias specify a purity of ≥ 58% for oleic acid.