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More than half of the drugs currently in use are chiral compounds, available as either racemates or pure enantiomers. With increasing substances of forensic interest falling within this category, chiral analysis is firmly under the forensic microscope. Chiral separation of drug enantiomers is essential in order to show that the active enantiomer is, in fact, present in your specimens.
In the past, chiral analysis has combined several processes. It would typically start with drug confirmation by a form of mass spectrometry (capillary electrophoresis CE-MS, gas chromatography GC-MS or liquid chromatography LC-MS) followed by separation of the enantiomers and impurities by a specific chiral separation technique, such as chiral capillary electrophoresis or chiral chromatography. It’s fair to say that this approach can be problematic, would you agree?
We’ve found that direct connection of chiral GC or LC columns with mass spectrometry provides, at best, marginal separation capability. But that’s not all. Neutral or highly sulfated cyclodextrin additives in chromatographic and electro-driven separation modes can cause contamination and ion suppression in the electrospray process. This is far from ideal!
Where does CESI-MS come in?
Have you heard of low flow Capillary Electrophoresis Electrospray Interface for Mass Spectrometry (CESI-MS) using a Partial Filling Technique (PFT)? It’s proven to generate chiral separation and produce quantitative data at the sensitivity that forensic toxicologists require for even the most challenging casework.
We put the method to the test in the tech note Chiral Analysis of Methamphetamine and Its Metabolite, Amphetamine in Urine by CESI-MS. This new technique separated the enantiomers of methamphetamine and its metabolite, amphetamine, in a single run, with great sensitivity.
Dried blood spot sampling technique was first introduced 55 years ago, and it has become the method of choice for newborn screening around the world. Anyone with children will remember that moment in the hospital when the nurse pricks the heel of your tiny new baby to squeeze out a few drops of blood onto a card. It’s an anxious moment but it’s over in a flash, and necessary to screen for rare but serious health conditions.
But what does this have to do with forensic testing of novel psychoactive substances, after all, it is quite a leap to talk about newborn babies and then onto designer drugs? While dried blood spot sampling and analysis had to overcome hurdles in the early days, particularly due to low analytical throughput, there is a very good reason for its increasing attention in recent years in other applications.
It offers a faster, simpler alternative to serum/plasma or whole blood analysis in drug monitoring for toxicological analysis. In the tech note LC-MS/MS Screening of 64 New Psychoactive Substances Using Dried Blood Spots (as an Alternative to Whole Blood) we demonstrate the advantages, and here’s a rundown:
The small sample volume also means that the concentration of the target analyte is potentially quite low (e.g., less than 1 ng/L), requiring a highly sensitive and selective analysis method for detection and quantification. But in theory, there isn’t a catch if there is a solution, mass spectrometry. It is now the most common technique reported in literature for dried blood spot analysis and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) sets the benchmark.
In our method, researchers use the highly sensitive QTRAP® LC-MS/MS in Multiple Reaction Monitoring (MRM) mode using the Scheduled MRM™ Algorithm. The method is applied to authentic samples, and results are compared to a validated whole blood method used for routine analysis of NPS, yielding similar results. LOD was between 1 and 10 ng/ml, no interference from matrix compounds was observed, and the method was proven to be specific and selective for the analytes.
Do you want a more efficient workflow for the forensic analysis of THC-COOH in hair samples? Yes! Do we know a simple, highly sensitive technique? You bet! Find out how you can detect THC-COOH in hair down to 0.2 pg/mg trace concentration levels with excellent accuracy (>95%) and precision (<15%).
Marijuana is the most widely used recreational drug in the world, with reported users as high as 234.1 million worldwide. Forensic toxicology labs face the task of testing hundreds of thousands of samples every year to identify drug misuse in relation to a range of civil and criminal investigations, such as intoxicated driving investigations, child custody cases, sexual assault cases, and parole abstinence monitoring.
The presence of the main marijuana metabolite - THC-COOH - can be detected in urine, blood, and saliva and indicate active drug use. While these biological fluids are valuable in determining use in the short term, hair testing offers an advantage due to its larger detection window. Consequently, for accurate detection of long-term cannabis use (up to 90 days), hair samples are far more reliable sources and are widely accepted in criminal and civil courts.
However, using hair for detecting cannabis does provide its own analytical challenges. Firstly, the concentration of THC-COOH in hair samples is characteristically low, and secondly, there is a high abundance of matrix interferences that specifically impact the detection of THC-COOH.
Efficient Workflow. Sensitive Detection. Accurate Results.
Presenting an efficiently designed analysis approach that gives accurate results. Our workflow combines the TripleQuad™ 4500 LC-MS/MS System with a solid phase extraction procedure that allows the reliable and sensitive detection of THC-COOH at trace levels (0.2 pg/mg) in hair matrix.
Top three highlights:
This workflow for the forensic analysis of THC-COOH in hair samples is ready to be integrated into your forensic toxicology laboratory. You will experience more accurate results with a more efficient workflow designed to support optimum throughput and sensitivity.
To read more about these topics above, take a look at our Forensics Compendium.
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