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Published on: May 25, 2021
GHB free acid: II. Isolation and spectroscopic characterization for forensic analysis
Mark R Witkowski1, Laura A Ciolino, James V Defrancesco
1US Food and Drug Administration Forensic Chemistry, Cincinnati, OH 45237, USA. mwitkows@ora.fda.gov
Journal of Forensic Sciences
|March 29, 2006
Summary
A new method using second derivative FT-IR spectroscopy allows for the detection of gamma-hydroxybutyric acid (GHB) free acid. This technique overcomes challenges in analyzing GHB free acid in forensic samples, especially when mixed with gamma-butyrolactone (GBL).
Area of Science:
- Forensic Chemistry
- Analytical Chemistry
- Spectroscopy
Background:
- Gamma-hydroxybutyric acid (GHB) free acid reference standards are unavailable, complicating forensic analysis.
- GHB free acid analysis is difficult due to its presence in aqueous solutions with gamma-butyrolactone (GBL).
- Interference from GBL's carbonyl band and water's O-H bend can mask GHB free acid's carbonyl band in FT-IR.
Purpose of the Study:
- To develop a method for analyzing GHB free acid in forensic samples.
- To address the masking effect of GBL and water on GHB free acid in FT-IR analysis.
- To prepare a GHB free acid reference standard for analytical verification.
Main Methods:
- Studied model solutions of beta-hydroxybutyric acid (BHB) and GBL to understand spectral masking.
- Employed second derivative Fourier transform infrared (FT-IR) spectroscopy to resolve the GHB free acid carbonyl band.
- Prepared GHB free acid reference material via reaction of its sodium salt with hydrochloric acid.
Main Results:
- Second derivative FT-IR spectroscopy successfully resolved the GHB free acid carbonyl band.
- A presumptive test for GHB free acid was developed and applied.
- GHB free acid reference material was prepared and its identity confirmed using FT-IR and proton NMR.
Conclusions:
- Second derivative FT-IR spectroscopy is effective for identifying GHB free acid in forensic analyses.
- The preparation of a GHB free acid reference standard facilitates accurate identification.
- The developed method aids in the analysis of GHB free acid in actual forensic exhibits.
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