Vacuum degasser

HPLC-MS analysis was performed with electrospray ionization (ESI) in a positive ion mode on QTrap® API-3200 mass spectrometer equipped with Shimadzu quaternary pump, vacuum degasser, DAD detector and autosampler (Shimadzu Scientific Instruments, Columbia, MD, USA). Data acquisition and data processing were performed by Analyst 1.4.2 software package (Applied Biosystems, Foster City, CA, USA). LC conditions including column and gradient composition remains same as explained in the earlier HPLC assay. Injection volumes were 30 µL for all samples. UV detector was set on 280 nm and MS was set in a range of 200 to 1700 amu. Total ion chromatogram was extracted for acylated peptide m/z to produce extracted ion chromatogram (EIC) and was compared with UV chromatogram to identify the native and acylated octreotide adducts.

HPLC-MS was performed using electrospray ionization (ESI) in positive ion mode on a QTrap® API-3200 mass spectrometer, equipped with Shimadzu quaternary pump, vacuum degasser, DAD detector and autosampler (Shimadzu Scientific Instruments, Columbia, MD, USA). Data acquisition and data processing were performed using Analyst 1.4.2 software package (Applied Biosystems, Foster City, CA, USA). LC conditions including column and gradient composition remains same as explained in the earlier HPLC assay. Injection volumes were 30 μl for all samples. UV detector was set on 280 nm and MS was set in range of 200 to 1700 amu. Extracted ion chromatogram for native and acylated peptide was obtained from total ion chromatogram and compared with UV chromatogram to identify native octreotide and chemically acylated adducts.