Term
|
Definition
| Set of known concentrations of standards analyzed at the same time as unknowns |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
Not used as much
Known amounts of standard added to each sample
Uses lots of unknown sample |
|
|
Term
|
Definition
Commonly used in toxicology
Useful where sample prep leads to loss of analytes
Cmpd added to unknown, distinguish IS from analyte of interest
Response ratios of analyte to a fixed quantity of IS plotted for multiple calibrators |
|
|
Term
|
Definition
R = 2*(t2-t1)/(Wb2+Wb1)
Recommended R ~2.0 |
|
|
Term
|
Definition
Neff = 5.54(t'R)^2/(W1/2)^2
Efficiency of column |
|
|
Term
|
Definition
Resolution and efficiency
Nitrogen- better resolution
Helium and Hydrogen- give up resolution, increase ability to have shorter run times |
|
|
Term
|
Definition
|
|
Term
|
Definition
Eddy diffusion term
Particle size distribution
Not as in important in HPLC |
|
|
Term
|
Definition
Longitudinal diffusion term
Proportional to time on column
Density of mobile phase affects
Increasing temperature causes molecules to diffuse more and move faster, B increases |
|
|
Term
|
Definition
Mass transfer term
Due to inadequate time for equilibrium between phases
Faster flow = less time |
|
|
Term
|
Definition
Want maximum sensitivity
Use of small sample amount |
|
|
Term
|
Definition
Not useful for complex samples with many compounds over wide BP range
Early cmpds bunched, heavier cmpds have long elution times with low peak heights |
|
|
Term
| GC Temperature Programming |
|
Definition
Use for samples with wide range of volatility, boiling points, or molecular weights
Uses low column temperatures to better separate early cmpds, increasing temps to speed the elution of more retained cmpds (cuts analysis time) |
|
|
Term
| GC Thermal Conductivity Detector (TCD) |
|
Definition
Most "universal", not very sensitive (1 ng)
Best for fixed gases: N2, O2, CO2, CO |
|
|
Term
| GC Flame Ionization Detector (FID) |
|
Definition
"Universal" for most organic compounds (10-100 pg)
Not sensitive to fixed gases or water
Requires H2 and "Zero Air" for flame
Most commonly used (being replaced by MS)
Drug quantitation |
|
|
Term
| GC Nitrogen-Phosphorus Detector (NPD) Alkali-Flame Ionization Detector (AFID) Thermoionic |
|
Definition
Selective for N or P containing cmpds
Was often used in drug and tox labs |
|
|
Term
GC Nitrogen-Phosphorus Detector (NPD)
Alkali-Flame Ionization Detector (AFID)
Thermoionic |
|
Definition
Selective for N or P containing cmpds (10 pg)
Drug analysis
Being replaced by MS detectors |
|
|
Term
| GC Electron Capture Detector (ECD) |
|
Definition
Selective for halogen, nitro, or aromatic cmpds (50 fg)
Not used often
Contains radioactive source (63Ni) |
|
|
Term
| GC Infrared Detector (GC-IRD) |
|
Definition
Universal for most organic cmpds
Not as sensitive as other detectors
Good for ID of isomers of cmpds where mass spectra are similar |
|
|
Term
|
Definition
Most widely used instrumental technique in chemistry lab
Samples not good- explosives (thermally unstable), low volatility materials, inorganic salts, fibers |
|
|
Term
| Mass Spectrometry- GC Detector |
|
Definition
Universal and specific (1 ng and 1 pg)
TIC- all ions in range
EIC or Selective Ion Monitor- selective |
|
|
Term
| MS Ion Source- Electron Impact (EI) |
|
Definition
Most common
Ions stream off tungsten filament to target
Hit and knock off electron to become positive |
|
|
Term
| MS Ion Source- Chemical Ionization (CI) |
|
Definition
Creates positive ion
Useful if a weak molecular ion under EI conditions
If cmpd fragments a lot |
|
|
Term
| MS Ion Source- Negative Chemical Ionization (NCI) |
|
Definition
Creates negative ion
Useful for explosives |
|
|
Term
| MS Ion Source- Electrospray Ionization |
|
Definition
Used with HPLC
Carrier gas
Droplets have a positive charges and accelerated across gap with potential |
|
|
Term
|
Definition
Matrix Assisted Laser Desorption Ionization
Used for large molecules
Pulse with photons of laser energy to blast off chunks
Ions streamed through TOF analyzer |
|
|
Term
| Mass Analyzer- Quadrapole |
|
Definition
Most common in forensics
Poles paired with fixed voltage or alternating current in radio frequency
Ions spirals down length of tube
Ions with specific mass can only make it down |
|
|
Term
|
Definition
Also frequently used
Ions oscillate inside- only right size will pass through
Alternating current |
|
|
Term
| Mass Analyzer- Ion Cyclotron Resonance |
|
Definition
|
|
Term
| Mass Analyzer- Time of Flight (TOF) |
|
Definition
Often used with MALDI
Energy potential becomes the source
Light ions move faster
Time it takes is proportional to mass
Can determine mass of ion up to 3 decimal places |
|
|
Term
| Mass Analyzer- Ion Mobility Spectrometer |
|
Definition
Electrodes accelerate ions
Similar to time of flight
Used as portable "sniffer" for drugs, explosives, and chemical warfare agents |
|
|
Term
| Mass Analyzer- Tandem MS/MS |
|
Definition
3 quadrapoles
Used with liquid chromatography to screen tox samples |
|
|
Term
| Total Ion Chromatogram (TIC) |
|
Definition
| Sum of intensities of all ion fragments |
|
|
Term
| Extracted Ion Chromatogram (EIC) |
|
Definition
Generally "post run" process
Can go back until you find what you want
Sum of selected ions from each scan
Reconstructed Ion Chromatogram
Fire debris analysis |
|
|
Term
| Single/Selective Ion Monitoring (SIM) |
|
Definition
Only a few specific ions scanned
More sensitive than normal scan
More data collection time at each ion
Toxicology- at of drug in bodily fluids is small
"Pre-run": set up prior to scan, extracts only selected ions
Can't go back |
|
|
Term
|
Definition
| Mass calibration done weekly with perfluorinated cmpds |
|
|
Term
|
Definition
Adjustment of ionization, repeller, and accelerator voltages
Most MSD have "auto-tune" |
|
|
Term
| Fire Debris Extraction Techniques |
|
Definition
Steam Distillation
Simple Headspace
Headspace Concentration- Passive (ASTM E1412 Activated Charcoal), Dynamic, SPME (Solid Phase Microextraction)
Solvent Extraction |
|
|
Term
| Instrumentation- Analysis of Ignitable Liquids |
|
Definition
|
|
Term
| Ignitable Liquid Classifications |
|
Definition
ASTM E1618-06
8 classes with 3 potential subclasses for each |
|
|
Term
|
Definition
Blended Product
C4-C12 with alkanes, aromatics, cycloparaffins
Aromatics most abundant group
Xylnes, C3 Castle, C4 Gang of four |
|
|
Term
| EIC Chromatogram Plots- Fire Debris |
|
Definition
| Alkanes Cycloalkanes Aromatics Napthenics Indanes |
|
|
Term
| Fire Debris Analysis- Class determinations |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| Cocaine salts/Base reagent= positive result requires all 3 |
|
|
Term
|
Definition
| Green for amphetamine and methamphetamine |
|
|
Term
| Confirmation Tests for Drugs- Categories of Analytical Techniques |
|
Definition
1 A and 1 B
2 Bs and 1 C
[image] |
|
|
Term
|
Definition
More suitable for thermally unstable cmpds- explosives
Samples must be particulate free |
|
|
Term
|
Definition
Precise volume
6 port loop injector often used
Fixed volume most reproducible |
|
|
Term
|
Definition
| Non-polar mobile phase with polar stationary phase |
|
|
Term
|
Definition
More polar mobile phase with stationary phase
Most commonly used |
|
|
Term
| HPLC Isocratic Solvent Selection |
|
Definition
One solvent mixture throughout entire analysis
Simple mixtures or polymer analysis |
|
|
Term
|
Definition
Changing from one solvent mixture to another over time during the run
Analogous to temperature programming in GC
Enhances separation of early eluting components while reducing elution time for later components |
|
|
Term
| HPLC UV/Visible Absorption Detectors |
|
Definition
Fixed wavelength
Variable wavelength
Diode array detection (multiwavelength) |
|
|
Term
|
Definition
Multiwavelength
Needs to absorb in UV or visible range
Lots of double bonds, aromatic character
Cmpds with saturated hydrocarbons don't work (fire debris)
Light absorbed and then split into specific wavelengths |
|
|
Term
| HPLC Fluorescence Detector |
|
Definition
More sensitive than absorbance detectors
Cmpd must fluoresce
Used for LSD |
|
|
Term
| HPLC Infrared Absorption Detector |
|
Definition
| Solvent interference restricts widespread application |
|
|
Term
| HPLC Refractive Index Detector (RI) |
|
Definition
Least sensitive
Best for non UV absorbers (sugars)
Not suitable for gradient elution
Reference side and sample size |
|
|
Term
| HPLC Mass Spectrometry Detector |
|
Definition
Becoming 2nd most common
Very sensitive
Solvent removal
Allows for better identification of peak |
|
|
Term
| HPLC Forensic Applications |
|
Definition
Drug tox- polar cmpds, metabolites, enantiomeric separation
Explosives- thermally unstable, good UV absorbers
Questioned documents- analysis of inks, dyes
Polymer analysis- size exclusion chromatography, fibers, plastics, adhesives |
|
|
Term
| UV/Vis Spectroscopy Cmpd Classes |
|
Definition
Aromatic compounds- controlled substances, metabolites, organic dyes and pigments, some explosives
Nitro compounds
Transition metal compounds |
|
|
Term
| IR Detector- Deuterated Triglycine Sulfate (DTGS) |
|
Definition
Most widely used detector in IR
Wide sensitivity range and quick response
Photoelectric transducer |
|
|
Term
| IR Detector- Mercury/Cadmium Telluride (MCT) |
|
Definition
Photoconducting transducer
Narrower sensitivity range, but more sensitive
Needs liquid nitrogen cooling to reduce thermal noise |
|
|
Term
|
Definition
Rough surface scatters light in all directions
Sample mixed with non-absorbing material (non-compressed KBr) or on surface of silica carbide paper |
|
|
Term
| IR Attenuated Total Reflectance |
|
Definition
Internal Reflectance- ATR commonly used
Good for opaque or other hard to hand samples (pastes, adhesives)
Doesn't require any big prep work |
|
|
Term
|
Definition
Controlled substances (crack cocaine vs. cocaine salt)
Automobile make, model, year from paint fragments
Polymers (fiber analysis, tapes, adhesives)
Infrared microscope- trace analysis, fibers, paint |
|
|
Term
|
Definition
|
|
Term
|
Definition
Aqueous solutions and glass sample containers can be used
Minimal sample prep |
|
|
Term
| Raman with FTIR- Fluorescence |
|
Definition
Much greater than Raman intensity
Broad background with superimposed Raman spectrum (hill with grass on top)
"Photobleaching" sometimes effective |
|
|
Term
| Raman with FTIR- Laser Power |
|
Definition
| Must be adjusted to prevent burning of trace sample- especially dark colored materials (black tar heroin, smokeless powder) |
|
|
Term
| Raman with FTIR Forensic Applications |
|
Definition
Seized drug analysis
Scan through baggies, glass vials
Minimal sample prep
Portable units available to take to clandestine lab scenes
Explosives analysis
Paints
Fibers and other polymers
Inks |
|
|
Term
|
Definition
Clearcoat
Effect coat
Basecoat
Surfacer
Electrocoat Primer |
|
|
Term
| Analysis Methods of Paint |
|
Definition
Solubility
Pyrolysis GC
FTIR Microscopy |
|
|
Term
|
Definition
| Polar silica stationary phase, relatively non-polar mobile phase |
|
|
Term
|
Definition
Most common
254 nm and 365 nm
Analyte absorbs UV- dark spot, bright bkd
No bkg fluorescence with 365 nm, but analyte may fluoresce |
|
|
Term
|
Definition
Iodine vapor (double bonds)- reversible
Conc. sulfuric acid w/heating |
|
|
Term
| TLC Group Specific Reagents |
|
Definition
Ninhydrin- amine groups
Iodoplatinate- drugs
Fast blue B- cannabinoids
Ehrlich- LSD
Diphenylcarbizone/HgSO4- barbiturates |
|
|
Term
| TLC Forensic Applications |
|
Definition
Drug screening
Ink analysis
Explosives screening |
|
|
Term
| Ink Analysis Forensic Applications |
|
Definition
Counterfeit currency
Authentication of historical documents
Written materials relative to another crime
Ink stain comparison |
|
|
Term
| Document Accelerated Aging Approaches |
|
Definition
UV Accelerated Aging- dye partially degraded, solvent still present
Thermal Accelerated Aging- solvent gone, dye intact |
|
|
Term
|
Definition
| Dye composition changes: HPLC-DAD and laser desorption MS Changes in ink solubility with time Solvent changes (evaporation) Changes in dye composition |
|
|
Term
|
Definition
TNT
PETN
ANFO
Nitroglycerin
HMX |
|
|
Term
|
Definition
Smokeless Powders
Black Powder (Pyrodex)
Pyrotechniques |
|
|
Term
|
Definition
Ball
Disk
Rod or tube
Characteristic of manufacturer and brand |
|
|
Term
| Explosive Analysis (Post Blast) |
|
Definition
GC/MS primary
HPLC and CE
SEC
TLC |
|
|
Term
| Explosive Device Detection (Pre Blast) |
|
Definition
Ion mobility spectroscopy (IMS)
Canine
X-ray imaging |
|
|
Term
| Metals Analysis- Flame Atomic Absorption |
|
Definition
Single element analysis
Least sensitive method
Best for alkali metals (Li, Na, K) |
|
|
Term
Metals Analysis- Graphite Furnace AA
Electrothermal or Flameless AA |
|
Definition
Single element
Good to ppb levels for some metals
Very small amts of sample |
|
|
Term
| Metals Analysis- Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) |
|
Definition
Simultaneous elements
Good to sub ppb levels (most sensitive) |
|
|
Term
| Metals Analysis- X-Ray Fluorescence |
|
Definition
|
|
Term
|
Definition
Best for toxicology
Simultaneous multi-element method
Very sensitive
Capable of isotopic composition of element |
|
|
Term
| Metals Analysis- Neutron Activation Analysis (NAA) |
|
Definition
Little or no pretreatment
Needs nuclear reactor as source of neutrons
Non-routine analysis
Specialized |
|
|
Term
| Metals Analysis Forensic Applications |
|
Definition
Bullet lead comparison
GSR
Explosives
Trace elements in glass (Laser Ablation ICP-MS)
Metallic poisons |
|
|
Term
| NIDA-10 Drugs (*NIDA-5 Drugs) |
|
Definition
Amphetamines*
Barbiturates
Benzodiazapines
Cannabinoids*
Cocaine*
LSD
Methadone
Opiates*
Phencyclidine(PCP)*
Propoxyphene |
|
|
Term
|
Definition
Salicylic acid
Pheylbutazone
2,4-Dinitrophenol |
|
|
Term
|
Definition
Acetominophen
Phenobarbital
Chlorothiazide |
|
|
Term
|
Definition
Morphine
Gabapentin
Benzoylecgonine |
|
|
Term
|
Definition
Amphetamine
Chlorcyclizine |
|
|
Term
|
Definition
| Whole blood centrifuged to remove cellular material, clotting factors still present |
|
|
Term
|
Definition
| Similar to plasma but does not have clotting factors |
|
|
Term
|
Definition
Elevated temperature
pH
Organic solvents
Enzymatic breakdown of protein or conjugate |
|
|
Term
| Tox GCMS Internal Standard |
|
Definition
| Deuterated drug or metabolite is best |
|
|
Term
|
Definition
SIM usually required for sensitivity
Target ion plus at least 2 confirmatory ions |
|
|
Term
|
Definition
Becoming preferred method
Minimal sample prep |
|
|
Term
|
Definition
|
|
Term
|
Definition
| OH band generally broader and more absorbing than free base |
|
|
Term
| Fingerprint Region in IR Spectrum |
|
Definition
|
|
Term
| Band found at 2350 cm-1 in a background KBr pellet |
|
Definition
| Carbon dioxide in the atmosphere |
|
|
Term
| Primary and Secondary Explosives |
|
Definition
Primary- shock sensitive
Secondary- requires detonator |
|
|
Term
| Vibrational Spectroscopies- Raman vs. IR |
|
Definition
Raman spectrum- inelastic scattering
IR- absorbance of light photons |
|
|
Term
|
Definition
Headspace sample
GC with FID
N-Proponal as IS |
|
|
