Syringe liquid chromatography

Successful use of modern liquid chromatography in the clinical laboratory requires an appreciation of the method s analytical characteristics. The quantitative reproducibility with respect to peak height or peak area is quite good. With a sample loop injector relative standard deviations better than 1% are to be expected. The variability of syringe injection (3-4% relative standard deviation) requires the use of an internal standard to reach the 1% level (2,27). 

Rebif is produced via recombinant DNA technology in a CHO cell line. It displays an identical amino acid sequence to that of native human IFN-P-la and, like the native product, is glycosylated. After cell culture the interferon is purified using a series of chromatographic steps (affinity, ion-exchange, gel-filtration and reverse-phase liquid chromatography). It is formulated as a sterile solution in pre-filled syringes and contains mannitol, HSA, sodium acetate, acetic acid and sodium hydroxide as excipients. It is administered subcutaneously three times weekly. 

For high-performance liquid chromatography (HPLC) analysis samples (0.5 mL) were clarified by centrifugation at 14000 Gav for 5 min and the supernatant was decanted, filtered through a 0.2 yim in-line syringe filter and analysed directly by chiral HPLC (see below). 

J,m poly(tetrafluoroethylene) (PTFE) syringe-tip filters High-performance liquid chromatography (HPLC) system equipped with Quaternary pump Diode array detector Vacuum degasser... 

The noncarbohydrate fraction can indeed be traced to lignin source. Gas-liquid chromatography of ether extracts of the washer liquors indicates the presence of guaiacol syringaldehyde, vanillin, vanillic acid, syringic acid, and hydroxybenzoic acid. 

Liquid Chromatography was performed on a Varian 8520 dual syringe pump liquid chromatograph. Two Vari-chrom variable wavelength detectors were used in series to provide a dual wavelength detection system. 

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