Improved Quantitation of Poly(Ethylene Glycol) in Various Matrices Using LC-MS

American Chemical Society
2005 Fall Scientific Meeting
Midland Local Section
Midland, MI
J.T. Roy
J. Lenartowicz

John T. Roy and Joshua Lenartowicz
Impact Analytical
1910 W. St. Andrews Rd.
Midland, MI 48640


A new approach for the analysis of poly(ethylene glycol) (PEG) was developed that utilizes liquid chromatography-mass spectrometry (LC-MS) with electrospray ionization and an ion trap mass spectrometer. The technique was used to detect this material in several different matrices. This procedure can be used for the direct analysis of PEG with different molecular weights that otherwise may be difficult to characterize by other techniques. The LC-MS procedure was used to monitor PEG in ethoxylated alcohols and in sodium bicarbonate buffering media that was used for the culture of human normal and neoplastic leukocytes. The LC-MS approach was also used to characterize PEG that was undergoing good laboratory practice (GLP) testing.

Quantitation was also desired for PEG in the sodium bicarbonate buffering media. The initial LC-MS conditions that were developed did not afford good quantitation for PEG due to poor linearity and precision. The current work has focused on improving quantitation with the LC-MS procedure. Utilizing ammonium acetate in the chromatographic eluent favors the formation of ammonium adducts versus other adducts, which has simplified the analysis procedure. Precision for the analysis has also been improved by using poly(propylene glycol) as an internal standard. Recent results that have been obtained for the quantitation of PEG in the sodium bicarbonate buffer solution will be presented.