Gas chromatographic-mass spectrometric identification and quantitation of benzyl alcohol in serum after derivatization with perfluorooctanoyl chloride: a new derivative.
Benzyl alcohol is commonly used as an antibacterial agent in a variety of pharmaceutical formulations. Several fatalities in neonates have been linked to benzyl alcohol poisoning. Most methods for measuring benzyl alcohol concentrations in serum utilize direct extraction followed by high-performance liquid chromatography. We describe here a novel derivatization of benzyl alcohol using perfluorooctanoyl chloride after extraction from human serum for analysis by gas chromatography-mass spectrometry (GC-MS). The derivative was eluted at a significantly higher temperature respective to underivatized molecule and the method was free from interferences from more volatile components in serum and hemolyzed specimens. Another advantage of this derivatization technique is the conversion of low-molecular-mass benzyl alcohol (Mr 108) to a high-molecular-mass derivative (Mr 504). The positive identification of benzyl alcohol can be achieved by observing a distinct molecular ion at m/z 504 as well as the base peak at m/z 91. Quantitation of benzyl alcohol in human serum can easily be achieved by using 3,4-dimethylphenol as an internal standard. The within run and between run precisions (using serum standard of benzyl alcohol: 25 mg/l) were 2.7% (mean=24.1, S.D.=0.66 mg/l, n = 8) and 4.2% (mean=24.3, S.D.=1.03 mg/l, n = 8), respectively. The assay was linear for the serum benzyl alcohol concentrations of 2 mg/l to 200 mg/l and the detection limit was 0.1 mg/l. We observed no carry-over (memory effect) problem in our assay as when 2 microl ethyl acetate was injected into the GC-MS system after analyzing serum specimens containing 200 mg/l of benzyl alcohol, we observed no peak for either benzyl alcohol or the internal standard in the total ion chromatogram.