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Published on: November 11, 2013
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Stability studies in biological fluids during post-analysis custody. Opiate compounds derived from heroin consumption
T Huertas1, C Jurado1, M Salguero1
1National Institute of Toxicology and Forensic Sciences, Sevilla, Spain.
Forensic Science International
|March 11, 2019
Summary
Forensic toxicology evidence stability is crucial. Heroin metabolites 6-MAM, MOR, and COD in blood and urine remain stable for a year when stored at -20°C, with blood samples requiring NaF preservative and urine samples buffered to pH 4.
Area of Science:
- Forensic Toxicology
- Analytical Chemistry
- Pharmacology
Background:
- Forensic toxicology requires long-term evidence storage, potentially altering drug concentrations.
- The stability of heroin-derived opiate compounds (6-MAM, MOR, COD) in biological samples post-analysis is not fully understood.
- Variations in storage conditions (temperature, preservatives, pH) can impact analyte integrity.
Purpose of the Study:
- To evaluate the in vitro stability of 6-acetylmorphine (6-MAM), morphine (MOR), and codeine (COD) in blood and urine samples.
- To determine the optimal storage conditions for maintaining the integrity of these opiate compounds during post-analysis custody for up to one year.
- To assess the impact of temperature, preservatives (blood), and pH (urine) on analyte stability.
Main Methods:
- Blood and urine samples were spiked with 6-MAM, MOR, and COD to a concentration of 1000 ng/mL.
- Samples were stored at 4°C and -20°C, with and without 1% NaF (blood) or at pH 4 and pH 8 (urine).
- Analyte concentrations were determined using GC-MS every two weeks for one year, with analyses performed in triplicate.
Main Results:
- In blood, 6-MAM degraded significantly under most conditions, with best recovery (47.1%) at -20°C with NaF after one year.
- Codeine (COD) showed high stability (>90% recovery) in all tested blood storage conditions.
- Morphine (MOR) stability varied, with recoveries ranging from 66.9% to 78.6% in blood.
- In urine, 6-MAM degraded at 4°C and pH 8, while MOR and COD remained stable across all conditions.
Conclusions:
- 6-acetylmorphine (6-MAM) is the most labile opiate compound, with its stability significantly influenced by storage temperature, blood preservatives, and urine pH.
- Optimal storage for heroin-derived opiate compounds in forensic samples involves freezing at -20°C.
- Blood samples should include 1% NaF preservative, and urine samples should be buffered to pH 4 to ensure long-term analyte stability.
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