Quantitation of the Polypeptide, Galanin, by Protein Precipitation and External Calibration LC/MS

Abstract

The quantitation of galanin from rat plasma was conducted using protein precipitation and LC/MS. This method was externally calibrated, as no suitable internal standard was available. Galanin was detected in the positive ion mode by selected ion monitoring of the 3⁺‐charge state. The lower limit of quantitation was 10 ng/mL and calibration curves were linear over the concentration range from 10 to 1,000 ng/mL. Within and between run precision and accuracy was less than 12% at all validation points. The method was demonstrated by a limited pharmacokinetic study of galanin in rats.

Keywords:

• Galanin
• LC‐MS
• Electrospray
• Polypeptide
• Absolute Quantitation
• Plasma