HPLC Coupled with Quadrupole Mass Spectrometry and Forensic Analysis of Cocaine.
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Transcript of HPLC Coupled with Quadrupole Mass Spectrometry and Forensic Analysis of Cocaine.
![Page 1: HPLC Coupled with Quadrupole Mass Spectrometry and Forensic Analysis of Cocaine.](https://reader036.fdocuments.us/reader036/viewer/2022062421/56649d045503460f949d7628/html5/thumbnails/1.jpg)
HPLC Coupled with Quadrupole Mass Spectrometry and
Forensic Analysis of Cocaine
![Page 2: HPLC Coupled with Quadrupole Mass Spectrometry and Forensic Analysis of Cocaine.](https://reader036.fdocuments.us/reader036/viewer/2022062421/56649d045503460f949d7628/html5/thumbnails/2.jpg)
Analysis of Cocaine
C17H21NO4
Molecular weight: 303.353 g/mol
• Important for forensics• Samples• An unknown powder• Could contain other
components• A human specimen• Fluids (urine, blood
saliva)• Hair
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HPLC: High performance liquid chromatography
• Sample injected using pressurized system
• Compounds travel through column at different rate– Interact with stationary phase
• Detection – Traditionally by UV absorption– More recently Mass
spectrometry• Better identification of unknowns
Typical Silica bead with C18 chains projecting off
![Page 4: HPLC Coupled with Quadrupole Mass Spectrometry and Forensic Analysis of Cocaine.](https://reader036.fdocuments.us/reader036/viewer/2022062421/56649d045503460f949d7628/html5/thumbnails/4.jpg)
Reverse Phase HPLC• Stationary Phase: small silica particles with long
hydrocarbons chains attached (non polar)• Mobile Phase: solvent, typically a water/alcohol
solution (polar)
Red compound is less polar than Blue compoundRed compound is present in a lower quantity
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Example HPLC ChromatogramsRetention time differences for cocaine and some of its metabolites
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Mass spectrometry
• Ion Source – Compound vaporized into gas phase – Energy added to ionize the compound• Excess energy may also fragment compound
– Most Common Method for cocaine: electrospray• Mass Analyzer – Fragments sorted based on mass/charge ratios– Ions detected
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Quadrupole Mass Spectrometry• Apply voltages to 4 parallel rods• Create an electric field • Can change voltages to scan through m/z ratios
Resonant ions will make it through to the detector
Non-resonant ions will be neutralized by hitting rod
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Mass Spectrometric identification of unknowns
•Quadrupole MS allows distinction of compounds with similar m/z•Compounds can also be distinguished by fragmentation patterns
Parent compound
Daughter ionsafter fragmentation
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Example Mass Spectra ResultsCocaine and its
metabolites have different mass spectra
and fragmentation patterns
Oral Samples (Subject’s Saliva)
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Applications
• Blood Gas Analysis• Allows for in vivo testing of gases present in the
blood• Analysis of stomach contents of overdose victims• Drug Profiling• Hair testing• Identification of unknown crime scene
specimens
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Recent Studies
• Detection in Human Specimens– Optimize separation and codetection of several
different drugs in urine
• Detection in Unknown Powder– Cocaine was identified in presence of metabolites
and other drugs from benzoylecgonine