Quantitation of Linear Polyethylenimines in Oligonucleotide Polyplexes by Liquid Chromatography-Charged Aerosol Detection (LC-CAD) (CAT#: STEM-CT-2165-CJ)

The Charged Aerosol Detector (CAD) is a detector used in conjunction with high-performance liquid chromatography (HPLC) and ultra high-performance liquid chromatography (UHPLC) to measure the amount of chemicals in a sample by creating charged aerosol particles which are detected using an electrometer.

Biochemistry; Biomedical; Biopharmaceuticals

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 positively-charged gas collides with the analyte particles. The charge is then transferred to the particles—the larger the particles, 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: Antibiotics; Excipients; Ions; Lipids; Natural Products; Biofuels; Sugars; Surfactants; Serum; Urine
• Equipment: Charged Aerosol Detectors; HPLC Instrument
• (Optional): Chromatographic column; Ultra-pure water

1. In comparison to other universal detectors such as refractive index (RI) and evaporative light scattering detectors (ELSD), CAD offers superior sensitivity and linearity. Depending on the chromatographic conditions, typically low ng limits of detection can be achieved.
2. As CAD measures the charge transferred to the particles it offers near-universal detection any non-volatile and most semi-volatile analytes, allowing you to see the full range of analytes in your sample.
3. The most desired feature of a near-universal detector like CAD is the ability to both quantitatively measure compounds incompatible with UV-Vis and MS detection and relative amounts of compounds when certified standards are not available for a single calibrant quantification.