Detection of diazepam in horse hair samples by mass spectrometric methods.

This research article describes a technique that allows for the detection of drug diazepam in horse hair samples using low resolution gas chromatography-mass spectrometry. It confirmed this method with two other techniques and successfully located the drug in samples for days after the final administration.

Development of A New Detection Method

• The researchers aimed to develop a method to detect the presence of diazepam, a commonly used drug, in horse hair samples using a technique known as low resolution gas chromatography-mass spectrometry (GC-MS).
• The primary purpose of this development is to monitor the administration of diazepam in racehorses where it may be used as a performance-enhancing substance.
• This technique can replace or supplement blood or urine tests which only provide detection for a brief period after administration.

Experiment Details and Sample Collection

• To test the method, two thoroughbred horses were administered several doses of diazepam, amounting to a total of 750mg and 200mg respectively.
• Hair samples were collected from different parts of the horses’ bodies including the coat on the neck, coat on the back, mane, and tail.
• The sample preparation used a technique previously implemented for human hair, which involved incubation with Sorensen buffer and solvent extraction.

Evaluation of the New Method

• The effectiveness of the detection method was evaluated by comparing it with two other techniques – gas chromatography-high-resolution mass spectrometry (GC-HRMS) and high-performance liquid chromatography-atmospheric pressure chemical-ionisation mass spectrometry (HPLC-APCI-MS-MS).
• In the first experiment, diazepam was detectable in the mane for at least 85 days after the last dose using low-resolution GC-MS.
• In the second experiment using the same technique, diazepam was discovered in the coat on the neck of the horse for up to 25 days following the last dose.
• The results obtained from low-resolution GC-MS were affirmed by the other two methods.
• Moreover, using GC-HRMS, diazepam was detectable for up to 38 days after a 200mg dosage was administered to the horse.

Conclusions

• The study demonstrated that low resolution GC-MS is capable of detecting diazepam in the hair of thoroughbred horses for an extended period after administration.
• These findings present new possibilities for the detection and control of the usage of performance-enhancing substances in horses, beyond the traditional urine and blood tests.